VW T4 Transporter 2.5tdi Misfire..Please help

[baloo]

Hi there, this is my first post and am at my wits end and really hopeful that someone out there can advise me on a misfire problem that i have had for a while now :confused:

The problem occured after adding diesel redex to the tank after i was getting smoke at startup (coincidence or not i'm not sure)

There is a set pattern to the problem now after driving the van for a few months while converting it:

1, if i start the van first thing in the morning and drive off immediatly then the van Fires on only 4 cylinders and doesn't clear even when warmed up.
2, if i start her up and let her tick over for just a couple of minutes then tickover smooths out and she runs fine if i just rev to about 2000rpm.

3, if taken on the motorway and driven at between 3 and 4000rpm for a few mile then she becomes rough (misfire) but if i pull off the motorway and pull over to the side of the road and just let her tick over for 4 or 5 minutes then she will drive great again if the rev's are kept down, smooth with no hint of a misfire.

4, and she has on the very odd occasion when driven hard run great and pulls like a train, running smooth. Once was when the AA came out and checked her over and was left ticking over for a good 25 minutes, she then ran perfect for a good 10 mile before the misfire returned :aargh4:

Basically, when i get the problem, i pull over and let her tickover, and the problem dissapears, but returns if driven above about 2000rpm.

So far, the van has been to one VW specialist (?) who had her for 3 days and said that there was no misfire! But on going out with the mechanic for a test drive, the van was far from running right, the mechanic thought the van "seemed to be ok"!

She comes back with no error codes (once when the AA plugged the van in and also at the above garage). I've also changed the fuel filter, air filter, return fuel pipes, MAF sensor and run her on a strong dose of FORT'E diesel injector cleaner for 10 mile up the motorway, i then filled the tank up and ran her with a slightly strong dose but no change.

I think it may be an injector playing up, lack of fuel pressure or fuel starvation to one injector maybe, as if i let her tick over she will run fine (if i don't rev over 2000rpm ( i can on occasions for a short burst rev higher, but any driving at higher revs (3 to 4ooorpm) brings the misfire back :banghead:

I want to take her somewhere where they can diagnose the problem, but am split between VW van center and a diesel specialist, if i knew it was an injector problem i would take her to a diesel injection specialist, but should I take her to VW and a possible bill that goes through the roof? :yikes:

Am hoping there is someone out there who can tell by the above symptoms what is most likely causing the misfire :1zhelp:

apologies for going on a bit here, and thanks for reading this if you got this far :beerchug:

Any help would be very much appreciated.

Baloo. (From the T4 forum)

[baloo]

Has anybody got any idea if this is a fuel injector problem?

Am also having a problem finding a diesel injection specialist in the west midlands, if anyone can recommend one?

To cut it short.......

1, if i start the van first thing in the morning and drive off immediatly then the van Fires on only 4 cylinders and doesn't clear even when warmed up.
2, if i start her up and let her tick over for just a couple of minutes then tickover smooths out and she runs fine if i just rev to about 2000rpm.

3, if taken on the motorway and driven at between 3 and 4000rpm for a few mile then she becomes rough (misfire) but if i pull off the motorway and pull over to the side of the road and just let her tick over for 4 or 5 minutes then she will drive great again if the rev's are kept down, smooth with no hint of a misfire.

4, and she has on the very odd occasion when driven hard run great and pulls like a train, running smooth. Once was when the AA came out and checked her over and was left ticking over for a good 25 minutes, she then ran perfect for a good 10 mile before the misfire returned :aargh4:

I did forget to mention that if i leave her ticking over she blows smoke out when driven off, and the longer i leave her ticking over the more smoke she blows.... this does eventually clear though and she runs fine if the revs are kept down.

Would i just be best taking her to VW? but with no error codes showing up would they just throw parts at the van at great expense to me?

Got to get this sorted in the next few weeks, need her running right for when i go away (hopefully)

any advice at this point like i've said would be very much apreciated :beerchug:

[a8 tech]

Sounds like the needle lift injector number 4 i think is sticking,its the injector with the two pin wiring and is used to calculate fuel injection timing especialy for piont of injection for stating.Sorry cant be of anymore help

[baloo]

Sounds like the needle lift injector number 4 i think is sticking,its the injector with the two pin wiring and is used to calculate fuel injection timing especialy for piont of injection for stating.Sorry cant be of anymore help

Hi a8 tech, thanks for the reply,

when you say injector number 4, i'm presuming you mean the larger one of the 5 injectors?

If it is an injector sticking, would VW be able to sort this or am i best finding a good diesel injector specialist..... which i am having problems finding at the moment.

Cheers, baloo.

[a8 tech]

Yes thats the injector which is called G80.If it was faulty you would notice the engine would sound louder due to diesel knock as ther would be no engine timing regulation.I would try indi diesel workshop first as they will also be able to test injector spray patterns unlike the dealer who will struggle without a fault code.Forgive me if i have missed this but have you changed the fuel filter,if no i would change it first and try that as it is never a bad idea to change the filter.There can be lots of reasons for your misfire but i would suspect there is a fuel delivary issue or reduced air flow.I am not here this week but i will check your post for any updates.Regards Jon

[baloo]

Hi Jon, at present i have changed, fuel filter, air filter, return pipes and have replaced the MAF.

I'm not very mechanically minded but will check the connections to the G80 injector just in case it is something as simple as that.

Will keep searching for a good diesel specialist locally but not having too much luck at the moment, if no luck i will have to think about taking her to VW to try and get this sorted..... but will continue my search for an injection specialist, a few places i've seen don't have any garage facilities, is it best for me to remove the injectors myself and take them in to be checked, or are there "drive in" injection specialists out there that i can't seem to find at the moment?

Thanks for your help,

Mart. (baloo)

[a8 tech]

You could wait for the misfire to occur and open the injector pipes one by one to locate the fault.If you do remove the injectors make sure you replace the copper o ring as they will be compressed and if you refit them you will lose compression.I would try and get the hole job done in one so they can see the running conditions first before making a diagnosis

[baloo]

cheers, the problem i have is that the misfire only occurs on initial start up and if left ticking over clears, and doesn't reappear unless i drive her with the rev's higher than 2000rpm (say motorway) i wish it was a permanent misfire as i could then do as you say.

Have cracked open the injectors and fuel is getting there, really need to find a decent specialist.

If i take the injector/s out then i will replace the copper O rings like you say thanks.

If anyone knows of a good diesel injection specialist then i'm all ears, I don't mind travelling if it isn't too far.

[baloo]

Forgot to mention, when i rev her up there is no apparent misfire, she sounds fine, it's only when she is driven that the misfire is there :confused: :aargh4:

I'm still looking for a diesel injection specialist in the west midlands, has anybody used these? http://www.carwood.co.uk/

[a8 tech]

Possible advance and retard sensor in the fuelpump if the fault only occurs under load.

[baloo]

Cheers Jon,

The van is now booked in at a diesel specialist week after next, hope the bill isn't going to be too big!

They did say that if the fuel pump has to come off to be checked then the cost could be anywhere between £350 and £700!!! have obviously said that i just want the injectors checked out first which is £150 to remove and check them, plus cost of replacement if needed.

I'm hoping it's just an injector thats clogged at this stage but am a little concerned that it could be a pump problem now you mention the advance and retard sensor, if it is this, does that mean the fuel pump has to be stripped down..... i presume so? (BIG BILL:aargh4: )

I've had a few bad experiences with garages in the past (not that all garages are the same) so was thinking about removing the injectors myself and taking them in and get those checked first, it can't be too difficult (said he!), just looks a bit tight for room in the engine bay, i had heard though that the front panel comes off and i think i also read somewhere that the radiator swings out for better access, would you know if this is the case, or like you said before is it just better to let them have the van?

Thanks for your help, and appologies if i've rambled on a bit here.

:beerchug: Mart.

[a8 tech]

Baloo you can remove the front panel and set the radiator in the service mode but still you face the issue of renoving the injector pipes.I can see your point with the pump but if you explain the fault fully and dont agree with the repair until the workshop has witnessed the fault and they may give you a better diagnois than i can from the info you have given me.I am sure there can be some agrement with the workshop as to a price for diagnosis and repair,you can only ask.Good luck and have faith in them

[baloo]

Cheers, I've more or less decided to let them have the van, they want to keep it till the following day, i was sort of hoping they might be able to diagnose and sort it on the day..... but i'm probably being a little too hopeful there.

I've only asked them to check the injectors out for now and to get back to me if they need to look into the pump, need to get it sorted as it's been like this now for nearly 3 month (been a bit busy converting it)

i'll let you know the outcome....... and i'll try and have some faith :Blush: past experiences and all that which i wont go into here (been stuffed 3 times)

Thanks for your help again, it's apreciated :beerchug:

[baloo]

UPDATE ON MISFIRE!!!!!!!

I'm far from happy at the moment :zx11: van has come back from the diesel specialist (who i won't mention their name yet!) All they say they have done is take the injectors out, cleaned them and tested them and have said their isn't any problem with them.

I have a bigger problem now though as the van is about 60% down on power and has no torque whatsoever, before it went in the garage the power was ok, it just had a misfire at higher revs and was lumpy in the morning but ran ok after if the revs were kept down. It now has no misfire, even though they say there was nothing wrong with the injectors, and starting the van on a morning now is fine, fires up first time and runs smooth, if let to tickover it now doesn't blow any smoke either, but is as flat as a pancake as regards power.

The garage have had the van back and put it on their diagnostics and come back with no errors and say they don't know why it now has this problem and have advised me to take it to the local VW Van Centre to plug it in there, basically they have killed the van as regards power delivery, which was a problem it didn't have originally.

Has anybody any idea's why this should happen just because the injectors have been removed, tested and replaced..... and tested ok!!

It's gone in with one lot of symptoms and come out with totally differant symptoms........ are they trying to rip me off here???????????

They also inform me that they can now check the pump at a cost of £275 to remove it and further £350 to test it with a new part that they replace before putting it on the test bench...... thats £625 + VAT to just test it, and no guarantees that it is the cause of the problem!!! If they tested it and then gave me a quote for putting it right i could stomach that, but to pay over £800 just to remove and test it!

So if anybody's got any idea's what they may have done here i would be very interested to hear..... i have got a bad feeling about this at the moment.

Cheers in advance,

Baloo.

[a8 tech]

http://forums.vwvortex.com/zeroforum?id=33 try this site it may help more than i can as i have no technical/diagnosis info for your engine type to give you some figures to the fueling and the air quantity.

[baloo]

Cheers, will take a look Jon :beerchug:

[baloo]

UPDATE......

The van has now been at VW for 3 days and they have been unable to find the problem, the turbo has been taken off and checked because they didn't think it was actuating, but the turbo checks out ok and they have managed to test it somehow and it does actuate but is not coming in when the engine is running.

they have also tried a known good ECU from a donor vehicle and this made no difference, all the vacuum pipes have been checked and all associated wiring, sensors etc, there are no fault codes coming up, the EGR is functioning correctly, the MAF has been checked and the reading was low but they say that this is a symptom and not the cause as they have also tried another MAF, they also say that the readings coming from the pump are within what they should be and now say they are stumped, i had to wait another day for their top technichian to come in to take a look but still no joy.
They have now collected all the information together, i.e. all tests that they have carried out so far, diagnostic data etc and from what they have said have forwarded this to there experts in germany so hopefully they can come up with a solution to the problem or give them some idea what to look at next.

It just seems funny that the original problems are now gone, hope i'm not repeating myself, starts in the morning and ticks over perfect immediatly, if left ticking over there is no smoke and no misfire when driven anymore, but all power (turbo boost/torque) has gone, it just drives through the rev range as if a 850cc trying to pull 2 ton :confused:

i've read a little about the N75 valve and wondered if this could cause this sort of problem? others have told me not to discount a blockage in the exhaust or could it be the fuel pump has been tampered with? but VW say that the readings from the pump are ok :dunno:

The van had the same constant symptoms for 4 months with no change, so why i keep asking myself has it all changed when all that was done(?) was the injectors were removed and put back in? i was even told there was no problem with them! so i ask myself..... where is the misfire etc?

Am hoping VW can come up with a diagnosis soon.

[a8 tech]

I think the intake shut off flap is shuting when it shouldnt and reducing the air flow hence air mass value will be reduced and no turbo activation.You could by pass this and give the turbo a direct vacum feed from the servo pipe to illiminate collapsed/leaking turbo solonoid pipe.

[baloo]

I think the intake shut off flap is shuting when it shouldnt and reducing the air flow hence air mass value will be reduced and no turbo activation.You could by pass this and give the turbo a direct vacum feed from the servo pipe to illiminate collapsed/leaking turbo solonoid pipe.

thanks for that Jon, i will pass that on to VW as soon as i can get in touch with their sevice dept, but i don't think they are there now till monday.

I'm not too mechanically minded and presume you mean the intake flap on the turbo?

Thanks for the other link, i have posted the same on there and waiting to see if i get any feedback cheers.

I'm hoping to use the van for holiday next week, but not sure if i'll have a van at the moment...... or any money thinking about it..... must keep head up :)

[a8 tech]

Hey baloo,i forgot you mentioned n75 to me so here is a explanation of its operation and expected fault code and power loss if it fails.(only slight power loss)
Solenoid valve for charge pressure
limitation N75

Solenoid valve N 75 is controlled by the
engine control unit. The vacuum in the
low-pressure box is set by changing the signal
clocks (pulse duty factor).




Effect of signal failure: Electrical circuit

The solenoid valve opens.
This produces atmospheric pressure in the
low-pressure box.
This corresponds to the adjustment used in
emergency operation.


Fault message of self-diagnosis:

Short to positive
Interruption/short to earth

[baloo]

Hey baloo,i forgot you mentioned n75 to me so here is a explanation of its operation and expected fault code and power loss if it fails.(only slight power loss)
Solenoid valve for charge pressure
limitation N75

Solenoid valve N 75 is controlled by the
engine control unit. The vacuum in the
low-pressure box is set by changing the signal
clocks (pulse duty factor).




Effect of signal failure: Electrical circuit

The solenoid valve opens.
This produces atmospheric pressure in the
low-pressure box.
This corresponds to the adjustment used in
emergency operation.


Fault message of self-diagnosis:

Short to positive
Interruption/short to earth



ERRRRR :confused: i see why i drive a forklift now :o:Blush: i'm understanding a little of that and will ask VW if the N75 could be the cause or be part of the problem.

If a problem with the N75 only causes slight power loss then i think it may not be the actual problem as the van does have a drastic loss in power.

i am getting a lot of help from other forums too and wondered what your opinion of the following is:

if the injector pump is run with one injector disconnected then the engine will run but 1 in every 5 injections will have none or very little back pressure to cushion the injector pump piston.
I would imagine that (in absolute worst case scenario) it could shatter something in the pump cylinder.

This could account for the symptoms. Blockage in the injector was the orginal problem which was cleared during the injector service and testing. Damaged caused afterwards to injector pump now causing a completely new fault.

and also:

From what I understand of injector pumps there is only one piston/cylinder with a rotating valve type thing to divert the charge to each injector in turn. If damage occurs in the pump then it's effects will be felt by all the injectors. For example if the bore is damaged then the diesel will leak past the piston and result in low pressure, this will mean that it could never achieve the higheir flow needed for hard acceloration or power at high revs. It would however be able to supply the required charge for stable tickover.

I'm not sure how plauseable this is, that's for the experts to determine but I would have to agree with you that what we have here is a new problem. It could be that there was crud in the injector pump which has now passed into a place where it is blocking the flow all the time, or your pump has been damaged some how.

The more and more i think about this the more i think it is an injector pump problem but don't know why VW have not considered this yet, in their defence though, they do say that the readings they are getting off the pump are ok, but if the pump was now damaged internally would vagcom or whatever tests they have run without removing the pump show that there was a problem?

I don't think i have mentioned this on this forum but i have found out that VW do have connections with the diesel specialist that checked the injectors.... they use them for all their diesel injection problems.... which is something i have to keep in mind, and if the pump does at some stage have to come off and be sent off to be checked then i would prefer it was sent to an alternative specialist.

I will ask about the N75 when i next speak to VW and am also going to ask if the donor vehicle they used for swapping the ECU over to check that, then could the pump also be swopped from that vehicle to at least discount that from being the cause.

I can't thank you enough for your help and appreciate you taking the time to read and reply to these longwinded essays i keep writing..... soz :o

Mart :beerchug:

[baloo]

sorry jon, have just been re-reading some of your messages and i think you answered this one :o

but if the pump was now damaged internally would vagcom or whatever tests they have run without removing the pump show that there was a problem?

They should be able to calculate the fueling by checking the dynamic timming and the looking at the amount of air being drawn in also

I think my memory is going now too soz :confused:

[a8 tech]

Yes there is a lot of real time info they can check and other systems would also be affected ie turbo and egr.You never know it may be somthing simple thats being overlooked like a vac pipe lose at the turbo,but instead of overcomplicating things lets see what they find.As it easy for people to give you advise on these forums but they have no come back on them and the vw workshop seem to be going about it correctly and they havent started to replace or misdiagnose so they can see the sympton and are eliminating the unrelated areas until they will be able to make a confirmation of the cause.I will only give advise but its hard to diagnose from 100 miles away but at least i can offer some explanations as to the workshops route.There is light at the end of the tunnel

[a8 tech]

You no what if the power wasnt a issue before and we know the injectors have been removed and cleaned and the refitted and then the new fault occured,then i as i said it might be a simple over looked issue,it would make sense to say that injector repair may be at fault.Sorry to mess with your head bot we re assuming the injector repair was 100%.This may be worth mentioning and eliminating by swapping off another engine as vw have swapped the ecu.

[baloo]

Yes there is a lot of real time info they can check and other systems would also be affected ie turbo and egr.You never know it may be somthing simple thats being overlooked like a vac pipe lose at the turbo,but instead of overcomplicating things lets see what they find.As it easy for people to give you advise on these forums but they have no come back on them and the vw workshop seem to be going about it correctly and they havent started to replace or misdiagnose so they can see the sympton and are eliminating the unrelated areas until they will be able to make a confirmation of the cause.I will only give advise but its hard to diagnose from 100 miles away but at least i can offer some explanations as to the workshops route.There is light at the end of the tunnel

Thanks, hopefully by tomorow i will be a little nearer to the end of that tunnel...... i'm just looking forward to having the van back, have just converted it and was hoping to get away these 2 weeks....

so for tonight i think it's chillout time:cool: and i won't be asking any more complicated questions tonight.... promise!

I am interested on how things work though, which probably accounts for asking some silly questions sometimes :o but as the old saying goes,if you don't ask you will never know :Blush:

Have just checked my mail, i was half way through this message, must type faster, i can't keep up at this rate:drive:

I had thought if they may have put the wrong injectors back in, is there a single stage injector? i wouldn't think they had but........

Will ask the question tomorrow as regards borrowing some injectors from the donor vehicle..... there won't be anything left of it at this rate, i was going to ask them if they could swap the pumps over too :D

I will mention it though, my note pads filling up slowly :beerchug:

Thanks again for the advice, i'm sticking with VW..... but next time i get a problem i'm tempted to come north.....100 mile aint that far.... i went down to penzance to get my windows fitted!

apologies for all these weird smily's!

Will keep you updated on how things progress tomorrow :beerchug:

mart.

[baloo]

You no what if the power wasnt a issue before and we know the injectors have been removed and cleaned and the refitted and then the new fault occured,then i as i said it might be a simple over looked issue,it would make sense to say that injector repair may be at fault.Sorry to mess with your head bot we re assuming the injector repair was 100%.This may be worth mentioning and eliminating by swapping off another engine as vw have swapped the ecu.

i sort of replied to this in my last post Jon, but just wanted to confirm that the power was there before the injectors were removed, i'm not sure if i mentioned this but the misfire when it occured would sometimes be worse than other days, it would vary a little, but as for power, the turbo defo came in and it had bags more power than what it did when it came back from the garage.

it's a definate case of one lot of symptoms being cured and another symptom taking there place.

i'll let you chillout now and have a cuppa.

will let you know how things go tomorrow.

mart.

[Freshup]

Hi, What a mission youve had. Just a hint. My first rule when something goes wrong, always look to the last thing you changed. My moneys on the injectors. Good luck. John

[baloo]

Hi, What a mission youve had. Just a hint. My first rule when something goes wrong, always look to the last thing you changed. My moneys on the injectors. Good luck. John

Hi, thanks john, yes... injectors could be a possibility, am hoping for better luck tomorrow and hope VW come back with some good news. mart.

[Freshup]

Just curious, what engine code (AHY,AJT,AXG etc) do you have?

[baloo]

Just curious, what engine code (AHY,AJT,AXG etc) do you have?

it's a 2.5tdi 88bhp AJT

[Freshup]

Thanks for that. Have engine manual but useless for diagnosis. Won't complicate issues further. I'll keep watching. John

[baloo]

no probs, am leaving it to VW now and keeping fingers crossed for some good news.

will know where to come for an engine manual if i need one some day, i can't believe that haynes don't do a manual for the later T4's

hope the weathers nice in New Zealand..... it's been raining here for about 6 weeks.

off to bed now in preparation for tomorrow.

mart.

[a8 tech]

Tell em to advance the timing and see what happens, and give the turbo a direct servo pipe feed so the wastegate isnt regulated,dont forget the p.m. and who to call and its not ghost busters:beerchug:

[baloo]

Cheers Jon, will tell them tomorrow :beerchug:

should make for an interesting debate :approve:

[a8 tech]

863Here is the kind of readings they can test to determine injection timing

[baloo]

Just a quick update here....

The van is still at VW, i went up and had a chat for nearly 1hr and 40mins with the mechanic yesterday to see what had been done so far and where we were going next. They have now carried out a compression test which has come back ok and tried advancing the pump. Im still in the position of still not knowing what the problem is and the next step tomorrow is to send the injectors off to be tested again.

I don't see it being the injectors causing the problem, surely all 5 injectors couldn't be faulty.... unless they were the wrong injectors?

Next stage after this i think is having the pump checked out, i won't mention the cost of having that done.... VW labour for removing and refitting and the actual cost of the test :yikes:

hopefully soon all will be revealed...... to be quite honest VW are running out of things to check/test now etc...... could be i left the handbrake on when i drove it and they have overlooked that :D

i won't be smiling when the bill comes though :eek:

[a8 tech]

Iam suprised the advancement hasent altered the performance and iam still concerned about the air volume but the injector issue should be sorted this time if they do what there saying there doing and rechecking,try and get the results of the spray test,as a certain amount of pressure is required to test the 2 stages and that is measured to work out the condition and the pattern of the nozzle

[baloo]

I'm no mechanic Jon (as you know) but i would have thought that VW would have seen a difference by advancing it, even if only minor, airflow as well is funny unless the pump isn't giving enough pressure at higher revs and this is maybe causing a low reading from the MAF, but if it is the other way round and the MAF's low reading is affecting fuel flow (ecu getting wrong info and not allowing enough fuel to be injected maybe... but VW have said the MAF isnt the cause from day one, and we are now into day 8 :confused:

Will see if i can have a copy of the spray test tomorrow, and i hope they are going to re-check them and things are on the straight and narrow here!

I still think all this will now come down to the pump though and i may insist it is sent to somewhere other than the garage in question.

Chinese has just turned up, might be my last for a while :mad:

will let you know how things go tomorrow. thanks again for all your help again, and hope the beer was good :beerchug:

[Freshup]

Hi,
Sad to see your saga continues. I would resist touching the injector pump. Besides the extreme cost, if servicing the injectors cured the initial problem then the pump is unlikely to have failed causing the second problems. Timing is absolutely critical on these engines and not too many mechs, including dealerships, spent enough time getting it spot on. However unless cam or injector pump belt have been disturbed timing should be ok. I did find 1 of my engines slipped the cog (minutely) on the end of the cam. There is no positive drive here, relying solely on friction to lock. The plus is it allows infinately variable adjustment. My money is still on injectors, not sure of G80's function but sounds a possibility. Your best bet may be 100mile drive to see A8tech.
Good luck
John

[baloo]

You have PM Freshup.

[baloo]

Just a quick update here.....

I am receiving a lot of help behind the scenes though, you know who you are cheers :beerchug:

DAY 9 AT VW

I'm no further forward :aargh4: apparently the machine they test the injectors with at the diesel specialist(?) is broke and they are waiting for it to be repaired!

so no news now till monday.

I would say more here.... but i might start ranting about how long this is taking to resolve!

I think 9 days says it all, i must say though that is only 7 working days!

[baloo]

Update

13 days at VW

Injectors were re-tested and an intermittent problem found,(the van has not got an intermittent problem now though!) injectors have now been refitted after repair and van STILL has the same problem with a loss in power.....

If anybody has any idea's whatsoever, even though VW have virtually exhausted all possibilities other than the pump. then i'm all ears. The pump by the way has been tested with vagcom and no errors are coming back, i know that the diagnostics can only check the position of the piston and takes it's reading from that and can only presume that the pump is injecting at the correct pressure and the correct quantity of fuel is being delivered...... so there could still be a problem with the pump, but it has only done 51000 miles and i would presume that the pump would not have worn out by now.

As i've said before the turbo is not boosting but this has been checked by VW and the turbo has been passed off as being ok, could a fuel delivery problem cause the turbo not to boost? The van starts great first time and fires on all 5 cylinders and runs with no apparent misfire now, but has a lack of power/boost which it did not have before the original test on the injectors.... which found no problem, injectors have been checked again now though and an intermittent problem was found, which would have cured the original symptoms... but they no longer exist, the problem now being and has been since the van came back originally from the specialist... a loss in power :confused:

Has anbody got ANY idea what could be causing this lack of power now?

Sorry for having repeated things here, but this is now dragging on too long, with no diagnosis and nowhere near finding the fault!

Also if someone could recommend a diesel injection specialist in the west midlands if it does come down to removing the pump and having it tested.

Thanks in advance for any help.

[a8 tech]

When they say they have checked the turbo did they also check if it is blowing air into the intake as if it is then there must be a restriction unless they still cant decide if the pump is delivaring required amount of fuel.Its fine checking the pressure to the wastegate but if the waste gate is stuck open then the air wont bloe into the engine so it will run like a normally aspirated engine and no fault code will show as n75 has done its job,this leads back to the low signal from the air mass which they established on day 1.Baloo i think we know that there is some mechanical fault here and it can only be fuel/air delivary.:beerchug:

[Freshup]

Couple of questions.
If the 2 small vacuum pipes on turbo were accidently reversed after testing, could this be the problem?
Does vagcom check throttle position?

[baloo]

When they say they have checked the turbo did they also check if it is blowing air into the intake as if it is then there must be a restriction unless they still cant decide if the pump is delivaring required amount of fuel.Its fine checking the pressure to the wastegate but if the waste gate is stuck open then the air wont bloe into the engine so it will run like a normally aspirated engine and no fault code will show as n75 has done its job,this leads back to the low signal from the air mass which they established on day 1.Baloo i think we know that there is some mechanical fault here and it can only be fuel/air delivary.:beerchug:

Hi Jon, i asked about the turbo and whether the wastegate valve could be stuck open, the person i spoke to was pretty confident that everything had been checked out with the turbo, I also mentioned the n75 valve to VW, they seem to think that the turbo is not the problem, but i am unsure if they have checked everything as i am still learning myself on how everything works. I would most probably be better speaking to the mechanic though and mention some of these things to him.

Ive been reading up about the O2 sensor in the ehaust, which i have read can cause these symptoms if faulty, also the hall sender which sends engine speed information to the ECU. Also something about blow off valve which vents off air metered by the maf, i'm not sure if this would cause this loss of power though, i don't understand too much about this.
Have also read about the air temperature sensor which modifys the fuel injection rate dependingon intake air temperature... but i wouldn't think this was the problem.

From what i have read, the O2 sensor could be possible and maybe the hall sender, but i would have thought these would have shown up on vagcom, and like you say it seems to be a mechanical problem.

Does vagcom show instantly if a sensor is not functioning right, or do VW have to test the readings off each individual sensor at different engine operating conditions?
Do they need to do more than just plug it into vagcom?

I keep thinking about the low reading on the MAF, and surely this must tell them something or give them some sort of clue where to look, i wonder if it would be a good idea to unplug the maf and see how the van runs then, have read that the ecu then uses set base values and obviously ignores the unplugged maf. worth a go?



Freshup Couple of questions.
If the 2 small vacuum pipes on turbo were accidently reversed after testing, could this be the problem?
Does vagcom check throttle position?




Hi freshup, i'm not sure about the vac pipes, something else i could ask them but being VW i would have thought that this would not have happened.... but who knows :confused: The throttle sensor on the pedal crossed my mind if that is what you are referring to, could it be the throttle position sensor is now faulty and not showing how far the
accelerator pedal has been depressed?
baloo :beerchug:

[Freshup]

Hello Mart,
It seems all previous work has now been checked.
From my experience lack of turbo boost generally results in black smoke at full throttle. I read somewhere that the electronic throttle unit on the injector pump are prone to sticking. This should be accessable without removing the pump. Thus my query about vagcom. Maybe A8tech may be able to enlighten us in this regard. Another thing to check, something new, the exhaust gas recirculation valve may be worth a shot.
Regards John

[baloo]

Hi john,

Update

Vw have phoned and said they have checked the resistance in the wiring they were concerned may be causing the problem and everything checks out, am now told that they have spoken to the master tech for VW and he is coming down Monday, so nothings going to happen now till then, this will be the 3rd week at VW..... i've become very patient in my old age :confused:

I think basically they have gone over what they have checked before, i never noticed any black smoke from exhaust john for the short time that i drove it with the new symptom, and i did have to give it full throttle to get anywhere.

The EGR was one of the first things that VW checked and they found no problems there, i also asked them about this. I'm not sure about the electronic throttle unit, if it's the part on the top of the pump you're talking about, which i think is the temperature sensor? then i think it should show up on vagcom if there is a problem, but i have read that the circuit boards can play up with the extremes in temperatures and affect the soldier joints, and have read that this doesn't always give an error code....... but saying that you can read allsorts on the net.

I'm praying that this master tech they say they are bringing in can put his finger on the problem, i've told them to chain him to the van till he's sussed it :D

Fingers crossed for monday :beerchug:

[Freshup]

Hi Mart,
Sorry I missed the EGR test was OK. It sounds like VW have followed the process of elimination pretty well, albeit slowly. Obviously one of those very rare events that defy logic. Invariably it's a simple thing in the end. Between the master tech and any reply from Germany I'm sure problem will be solved. Have consulted Germany direct myself, some years ago, and found them to be on the ball. Anyway Monday's not that far away and looking forward to the final chapter.
Regards
John

[a8 tech]

Me thinks said master tech may resolve the issue by looking in measure value blocks to determine fueling , point of injection,air volume and turbo input/output

[baloo]

Hi John and Jon :beerchug:

I can't stop long i've got visitors tonight soz, no need to apologies John about the EGR, i've got that many things going round in my head i'm brain dead at the moment :o

Cheers Jon, i hope their master tech does manage to solve this, i might start getting seriously worried if they say he can't find anything :aargh4:

Anyways, better go, lets hope this is the final chapter thanks.

Speak soon :beerchug:

[baloo]

This is not the final chapter....... as i thought it might not be! The master tech who was coming to sort the van today just happened to break his arm the weekend so i'm told! The van is now being taken to another van centre where they are now hopeful again of sorting this problem.

18 DAYS at VW!

[baloo]

Just a quick update here.....

The van has been at the 2nd VW van centre since tuesday and today they tried another ECU (new one) and still got the same problems, their master tech has now diagnosed the turbo, as no faults can be found anywhere else.

A new turbo has been ordered and will be fitted at the 1st VW van centre monday so i am told.

Will update monday on any news, fingers crossed...... again!


22 DAYS AT VW

[a8 tech]

At last some one has diagnosed the turbo yeha.You will probably find the waste gate is siezed/snapped hence the original concern on the amount of air/fuel ratio as no fault code genraly means mechanical defect.

[baloo]

I really hope you are right Jon, quick question..... and i've probably got the answer mixed up in my head somewhere :o would the MAF give a lower than normal airflow reading if the wastegate was knackered?

cheers, mart.

[a8 tech]

yes i would say so as the air flow may back up and what should flow past it will be forced back/recirculated,but as i said ages ago put a direct feed to the wastegate and drive it to see what happens as the wastegate is either open or closed and the inducted air should blow through in theory and power restored or at least here the turbine spin.If the air flow is reduced on a diesel then power loss is for sure as the engine needs more air than fuel,the more air the better.

[baloo]

Cheers Jon, i just don't understand then why VW haven't done this to test it and are presuming it is the turbo based on they can't find any faults anywhere else :dunno:

I'm hoping it is the turbo now and finally get this resolved.

I still have doubts though as they like i've said haven't found a specific fault with the turbo :confused: they say they will not charge me if it isn't the turbo....... but why not do like you say, which i have mentioned to them before what you have said about testing it.

heres hoping for good news monday!

[Freshup]

For Pete's sake.
It sounds like your VW or any master tech are no different the world over. As technology advances, so basic mechanical knowhow declines. Fit new parts, one by one, until problem solved. Simple checks like Jon has suggested all along are elementary mechanics. Obviously these guys can't read either as these simple tests are clearly detailed in VW workshop manuals.
One word of caution. One of my t4's had a UK aftermarket turbo/intercooler fitted when I got her. The turbo failed which I had rebuilt by turbo shop($NZ1600- 550 quid) , only to fail again after 800km. Apparently the oil supply pipe gets a carbon buildup due to the high temps. Minute carbon particles were dislodged while replacing turbo and restricted the small oil galleries in the turbo causing 2nd failure. It was only then I was told that this pipe should be removed and ultrasonically, or some other fancy name, cleaned. Expensive mistake on my part. Anyway T4 is no longer turboed, tune myself and still goes better than my other factory standard T4.
Good luck for Monday
John

[a8 tech]

Fresh up iam a master tech.Its ok iam not offended but your are correct passion and common sense need to be there as well as the qualification.

[Freshup]

Hi A8tech. Sorry, no offence intended. Having qualified in N.Z. myself 30+ years ago it's been very frustrating following this saga. Been owner operating a small transport fleet ever since, everything from wheelbarrows to 44 tonners. My policy has been to have all work carried out by dealerships while vehicles are under warrenty. Fortunately, due to the high mileages we cover, this has normally only been the first 12 months. Apart from specialised stuff where very expensive test gear is needed, I do all other repairs.
If one of my vehicles had been in the "shop" for 22 days for something like this, I'd be broke.
Even with my operating and mechanical experience I find it difficult to "get through" to some of these dealerships when problems arise. For baloo, a self-confessed, layman, it must be practically impossible to pass on the basic information you have provided thru the forum.
Most dealerships over here have a "holier than thou" approach. If it can't be diagnosed with a laptop, it's not broke. Nothing is repaired, just replaced. Manufacturers don't help by only supplying service units.

Get my drift.
sorry for the rant.

[a8 tech]

No problem at all and i would love to live in n.z,my wifes sister is moving to auz and they have asked us to go as well,audi uk said there woud be no problem finding employnent with audi in auz so i wonder if n.z have audi dealers.I feelin love with the place after watching lord of the rings and i hate england its becoming more americanised every day as people/customers have become so demanding and unrealistic.I have had it with this country i wish to flee before its overwelmed by imigrants form eu

[Freshup]

N. Z. has a strong VAG following with associated dealer network. Auckland is by far the biggest city. 1.2m people, total pop 4.1m. Countryside not unlike the UK although possibly more temperate. Giltrap Motor Group have major marques under their umbrella. Giltrap Prestige covers VW, AUDI, SEAT, SKODA, BENTLEY. Near new workshop and I bet could really use an A8tech as yourself. NZ has one of the lowest unemployment rates (<3.8%) in the OECD and the country is screaming out for skilled people. Come visit one day and I'll show you around.
John

[a8 tech]

Thanks Freahup,i may take you up on that offer as the fishing down there is world class and i think my kids deserve better than this country can offer.:beerchug:

[baloo]

hi a8tech and freshup, i didn't realise everybody was about to jet off to NZ, i haven't had any emails saying there were any new posts :( am i to late....... can i come :o

I know what you mean about foreign imports a8tech, am surrounded by them where i work, but suppose i shouldn't really say that, i'm not being racists in the slightest, but my pay won't increase where i am now, as they are employing our friends from abroad on even less money than what i am on and given a year or so i will be on minmum wage too...... no pay rise for the last 5 years...... time to look for pastures new.

I have been thinking of selling up and moving to scotland and living in the van and sod the system..... but of first all i need a van to do that :biglaugh:

Going back to the van for a second..... i still can't believe that VW haven't tested the turbo and actually diagnosed an actual fault with it, even though the first dealership did say they had tested it and said it wasn't at fault, this was done in th efirst 2 days (unless they have but would rather sell me a turbo, why not fit the turbo at the 2nd dealership?) sort of got me thinking again as to why they were taking it back to the first dealership on a hunch that the turbo was the cause, why not leave it at the dealership it is at now just in case it isn't the turbo :confused: the first dealership couldn't find a problem, so if it isn't the turbo then i'm back to square one and it WILL be time to phone Customer Care.

oh, and another delay...the turbo won't be fitted till tuesday now, this could be genuine though and they may not be able to get one for monday now.

Anyways, i won't rant all night :o hope it's a nice day on the other side of the planet, or as someone as asked me to say "in the land of the long white cloud" :Blush:

end of the day here for me and a8tech, suns a shinin and it's quite a nice evening.... time for some tea i think........

will update when i next hear anything.

A month this thursday coming if Paul Willis (head of VW UK is watching this thread)

baloo :beerchug:

[Freshup]

Kia Ora (Moari word for hello, good day, thank you etc) from "the land of the long white cloud"(N.Z.)
A8 anytime, I'll even organise some fishing for us. Baloo you're welcome too. Pictures (attached I hope) of brother in laws boat, although he's lost that:( along with wife.
Regards John

[baloo]

kia ora John,

i've got to say thats one giant gudgeon you've got there, sorry to hear you lost your fishing boat, i always stuck to piers and canalsides.... can't swim so sort of played it safe in the past, although i did have one dodgy moment in a boat on lake windermere when a storm came in and the water got really choppy, kind of found it entertaining at the time forgetting that i couldn't swim.... but did make it back to dry land :Blush:

Would love to visit NZ one day if finances allow, have a friend who has lived out there, so have heard quite a lot about it.... and the scenery looks great..... my sort of holiday, same reason i like hanging around Scotland whenever i can.

update

VW have just phoned to confirm that the turbo WILL be fitted tomorrow, and i will receive a phonecall tomorrow afternoon once they have road tested the van......FINGERS CROSSED! If this doesn't finally resolve the problem then i will be phoning Customer Care to inform them of the situation..... i think nearly a month is quite long enough. (sorry, am i repeating myself?)

Anyways......

Weathers not been too bad today john...... but we've had a weather warning for tomorrow with high winds and more heavy rain again, your winters probably been better than our summer :(

Hope to bring some good news tomorrow!


mart.

[baloo]

Will update here next week depending on what answers i get from VW.... but needless to say i am still experiencing problems!

[a8 tech]

992 here you go away of testing the turbo off the car and these are vag tools:beerchug:

[mazz]

hi ballo any news on your van yet as have a similar problem on my van ,van is flat as you like but is showing no fault codes at all ,so far i have changed MAF ,redone fuel pump timing and checked cam belt timing ,problem started as intermitent fault on way to germany ,first sign of problem was cruise control stopped working as soon as you hit a hill ,then van just got slower and slower,then after about another 200 miles van started running sweet again apart from fact that water pump bearings collapsed ,although cam belt did not break it come very close. changed pump and cambelt on campsite in berlin ,and continued holiday where van was running well sweet ,come home and got off ferry in dover and van started slowly losing power getting worse and worse untill it reached the stage it is at now "guttless" i am a fully qualified auto electrician and have been in motor trade 25 years and really know my vw tdis (have fitted sevral tdis in old vw buses)but this problem is getting the better of me

[baloo]

992 here you go away of testing the turbo off the car and these are vag tools:beerchug:

cheers jon

[baloo]

Hi Mazz,

I'm still having problems and I won't go into details at the moment, but if VW do manage to sort this i will let you know of their findings and maybe it will be of help to you.

If you manage to sort yours first i would be very interested to know what is causing your problems, as it sounds pretty similar to mine, as in no error codes ect.

best of luck with yours.....

baloo.

[bora(ing) nick]

Will this saga ever end... It has been a good read though.

You probably could've bought a new van for what VW are going to charge labour wise...

Good luck

Nick

[a8 tech]

http://volkswagen.msk.ru/engine/aab_acv/aab_acv_charge_air_syst.pdf (english bits)

[baloo]

have just had a look at the link jon but it says "This information accessible only from main page" and i'm a bit rusty with my greek :confused:

[a8 tech]

http://volkswagen.msk.ru/. click on this then the english bits are on the left hand side,there is loads of info in for vag stuff but i cant find your engine but it will be there.Found pump timing http://volkswagen.msk.ru/engine/aab_acv/aab_acv_disassembl.pdfg from main page goto the left and you will see engines,click and open and scroll down till you find aab/acv (engine codes and open it,this wiil shoe you the process of checking the pump timing with a dti never lie gauge.

[baloo]

have had a look jon, my engine is the AJT which i can't see there but will have another look cheers :beerchug:

[a8 tech]

But it gives you the genral idea and some info to throw at the maniacs who are playing with your van,i am chuffed with this site as its free info for me

[baloo]

cheers jon, any info is good and much appreciated....... and may come in handy. will keep you updated on proceedings :beerchug:

[mazz]

actually spent some time on my T4 today and sotred problem,:D it was a blocked cat ,dropped cat off this eve and took up road and to be pleasantly surprised by very rapid acceleration,so ive pulled cat off and smashed out honeycomb refitted and he is flying again ,seems quicker then it was before plus added bonus of a lot more turbo whooshing noise ,so my advice to you is to ask vw have they checked cat especially as it has low MAP sensor readings as this could be down to the fact the engine is unable to breath,also misfire could of caused cat to block up ,if it becomes magically fixed make sure they have not secretly changed cat as they should of checked this a long time ago,this is really only the 5th hour i have spent on this problem

[baloo]

UPDATE

Cheers Mazz, I did mention the exhaust and blockages some time back and VW said that they had already had the exhaust off, i don't know if it may have been a good idea to have road tested the van without the cat on, and it just happens that the exhaust now has a rattle which it didn't have before, could this be the cat breakng down??? I would have thought they would have fully checked for this though??? saying that, they have just changed the vacuum pipes.... after replacing the turbo???? they did check the vacuum pipes early in the investigation but surely these could have been changed if they were not 100% sure about them then. The turbo they say is faulty but say they cannot find a fault with it, they even tested it on the 2nd day and said it was working fine, now they say it is faulty, even though the road test i had when they said it was now fixed and power restored, was conclusive in the fact that the turbo was NOT boosting!
The only work done last week was to change the vacuum pipes, and this was delayed because they said that someone had been in that morning and bought all the vacuum pipe??? :dunno: this didn't work either and said that there was no improvement, even though last week they said the van was fixed! :confused::zx11:

They were supposed to be testing the fuel pressure as well last week, even though i had asked them some time back if they could do this to make sure there wasn't a fuel pressure problem.... and they said they couldn't, but apparently VW Germany have now instructed them to do just this, with equipment they have available???? they then phoned me to say they had not got the pressure figures to work to, but would test another T4 they had in to get some comparable figures to compare to mine..... no one phoned so don't even know if this was done.

Have now contacted VW Customer Care as i think a month and a half is more than enough time to have at least found something! And i am not impressed with the fact that items are now being replaced even though no fault can be found with them, i have however told them to keep my old turbo as obviously the new turbo has NOT fixed the problem!

Am glad you have yours sorted though, makes me wonder if i should have had a mess first and maybe i would have dropped lucky.

This on a whole isn't very good reading for VW and can only hope things improve.

Baloo

[baloo]

short update

I am still waiting for them to test the fuel pressure, apparently they are still working on the other van they need to get some comparable readings from :dunno: that will be another week shortly. I also await a response from customer care.

[baloo]

update.....

low and behold the van i was waiting for VW to finish work on so they could take some fuel pressure readings to compare to mine was picked up this morning and they were unable to do what they promised they would. :aargh4:

I do find it unbelievable that they would want to mess with another customers vehicle so as to be able to perform work on mine and to be quite honest i would not like it myself if they had been messing with my vehicle in this way..... but they promised to do this so as to be able to check the fuel pressure coming from the injector pump.... Germany have asked them to do this test but so the dealer says germany are unable to give them the fuel pressure readings so the can actually do this!? The dealer also says that germany haven't or won't give them these fuel pressure figures..... i'm sure that VW Germany if they ask them nice would be able to forward this information to them, the other options i have now given them is to aproach the diesel specialist who they have had a good relationship with for over 3 years (so they tell me) and ask them for the figures they need, he questioned whether they would do this for them! This whole saga is becoming more and more unbelievable, he can't tell me (but he did) that a company who VW have had a good relationship with for over 3 years and who do there injection work won't give these figures to them. The other option is to test my fuel pump and get some figures on the table and ring round diesel specialists or even phone Germany or Bosch and ask them if the figures are correct..... it's not bloody rocket science is it. With the amount of work i am doing and time spent trying to organise them.... they should be bloody paying me at the end of this!

The mechanic also thinks the van is running better now, i asked what they have done then..... nothing.... so how can it be running better, have explained to them how a turbo boosts power at certain revs and my van is not responding as it should considering it has a turbo attached to the engine.

I await the next phone call......

baloo

Does anybody out there know the fuel injection pump pressure figures for a 2003 2.5tdi 88bhp VW T4 transporter, would be of much help if anybody has this information, would prefer you PM me it just in case VW want to steal this top secret information :biglaugh: seriously though if anybody knows these figures then it would help :beerchug:

[mazz]

i pressume your van is in birmingham van center ,if it is i am not surprised they have not fixed it,as i have heard and personnally had nothing but poor service from these ,i have worked at dealers and no fault should take this long to fix ,espaically a present fault ,the only time we have spent over a week on running problems was when they were intermitent and that was working for renault ,truely the worse vehicles on the road,
have they give you a indication of bill yet ?,shame vw seperated from MAN dealerships because they the fitters at MAN west midlands were spot on

[mojogoes]

You could try contacting Allard motorsport who race diesels and have had lots of experience with tdi's especially vw tdi's or collins diesel specialists...ask for Sue who knows just about everything about you motor.

All that said , after reading your first post the first question that i would have asked would have been....is the van in standard form or has it got a tuning box fitted....if you had then said it had i would have suggested you take it off.

If on the other hand it was still in standard form i would have asked you if it smokes quite badly...if yes then it could have been a leak either on the smaller vacuum hoses or your inter cooler pipe work......but i have read that this is not the case.......i know you have replace or checked some if not all that i've suggested plus the usual maf sensor / m18 valve and n75 valves.

I have a mk3 90hp golf and i take it that your 2.5L tdi has a very similar fuel pump which also has a LOW PRESSURE CASE VALVE.....sometimes this valve especially on my type of pump (Bosch VE37) partially or fully falls out......it usually comes in 3 parts (a spring / inner and outer type collits) if the inner part partially comes out or in some cases the entier assembley falls out the low case pressure of around 40psi in the ve37's case is lost or lowered enough not to be able to feed the main pump pressure at higher rpm..................ask VW or someone to check this out.!!!

[mojogoes]

By the way i forgot to mention this very important point.......even when taking injectors to a diesel specialist.......first ask them "if my injectors/nozzles need cleaning how are you going to do it" , i say this because there is only one way of cleaning nozzles and that's SONICLLY and not with some brake cleaner/paraffin/petrol/diesel fuel and a RAG like they seamed to have done in your case............that's why it ran like crap when you got it back.....and never feel bad about naming and shaming........there's too many idiot diesel mechanics out there bullshitting nowadays as it is...lead by the VW STEELASHIP in !st place!!!! UUmmmm.

Who clearly want to fit a new fuel pump to just about every tdi that comes into the shop!!

[baloo]

Hi all, Right first things first..... today i have been informed that they (VW) are going to remove the pump and send it off to be tested at their cost, this was the least i think they could do to partly compensate for the inconvenience that this has caused over the past 6 weeks.... not to mention other datails that i have mentioned previously. I just need to trust them now to actually do this... but i have said all along that if the van comes back other than running right, i WILL take it to an independant specialist to check it over, diagnostics, ecu values turbo boost figures etc.

Everything so i have been informed has been checked, diagnostics are showing no errors, i've mentioned the N75 valve etc in the past and they say that everything checks out, they even said, like i have already mentioned, the turbo checked out ok on the 2nd day, but they ended up replacing it anyway, saying it must be that.... no faults found on it!? I think you have already realised after reading this thread that the van was totally standard with no tuning box etc and only having covered 50,000 miles (hardly run in) The only smoke i got was if i left the van ticking over for some time and this was very apparent, but the symptoms have moved on from there after the deisel specialist found nothing wrong with the injectors but magically cured the original symptoms (misfire) i did not get any smoke whilst driving the vehicle, just a total lack of power when it came back from said diesel specialist.

As regards the diesel specialist, they are not what i would say a small company and their website shows in detail the test/diagnostic equipment they use, i do think that they would sonically clean injectors because i did not rate them as a back street outfit when i first looked into them.

I would like to know exactly which bosch pump my vehicle has and will mention the low pressure case valve, but as i've said they have now agreed to remove the pump and send it to be tested. so hopefully if it is something like this then it will be spotted, i have to trust VW now to do what they say they will do, but they know that i will be taking the van to an independant specialist to be checked over if it does not return other than running as it should, i will probably be doing this even if VW do cure this problem just for peace of mind.

if this had been an intermittent problem then i could have understood a little better the problems that they may have, but the problem is far from being intermittent. I am not going to name which dealership it has been to (2 actually) as this has not come to a happy conclusion yet and if i do have to take this further it is probably better i don't mention.

Anyways, all i ever wanted on the 19th July when i took the van to VW was for them to diagnose what the problem was.... i never envisaged for one moment that they would still have it 6 weeks on.

I await the next phone call.

baloo.

:beerchug:

[bling69]

first of all , u get smoke on every diesel engine on start up a puff of black smoke , adding redex was a mistake , wats happend is that al the ' crap ' in the tank , the redex has broken it up into bits and its gone into ur fuel filter , causing blockage , and slowly making its way into the injecter pump and maybe injectors , wat u need to do is , drop the tank , get rid off the old fuel in it jet was the tank , replace , tank , u will find 2 fuel lines going from tank into the fuel filter , u want to get a powerful air compresser and blow it out , replace fuel filter and also blow the 2 pipes from the filter into the injector pump , other wise u will smash ur pump and thats costly.... try that and see how u get on.

[mojogoes]

Good point Bling69...but as said its all too late as vw will now fit a new pump i can guarantee that....and boloo know doubt they were a large creditable diesel specialist.........but they also didn't solve your small problem either did they....nor have the vw *******ship but hay like someone has already stated if they change enough parts they just mite have the van running as it should be.

[baloo]

first of all , u get smoke on every diesel engine on start up a puff of black smoke , adding redex was a mistake , wats happend is that al the ' crap ' in the tank , the redex has broken it up into bits and its gone into ur fuel filter , causing blockage , and slowly making its way into the injecter pump and maybe injectors , wat u need to do is , drop the tank , get rid off the old fuel in it jet was the tank , replace , tank , u will find 2 fuel lines going from tank into the fuel filter , u want to get a powerful air compresser and blow it out , replace fuel filter and also blow the 2 pipes from the filter into the injector pump , other wise u will smash ur pump and thats costly.... try that and see how u get on.

I must say bling that the van didn't blow any smoke whatsoever when i first had it, but did start to blow a little at start up after i had had it a while, so added the diesel redex, a week later misfire appeared at prolonged higher revs, van taken to diesel specialist where no problems were found with injectors, but original symptoms had dissapeared and were replaced with a total loss in power, VW then replace turbo which doesn't cure problem.
The van has covered just 50,000 miles and the fuel filter had been changed about 6,000 miles in a service before i had it, i would not have expected that much crap in the tank considering the age and definatley no rot as the tank is plastic, if there had been that much crap in the system then i would have expected more than a misfire on one injector. I again changed the fuel filter afte the misfire appeared and there was no visible crap in the filter, also VW have again changed the fuel filter and have run the van on a seperate fuel supply, all this after the injectors went back to said diesel specialist to be retested and this time they did find an intermittent fault with one injector, something i find very suspicious because the van did not have an intermittent problem at this time. The intermittent fault with the one injector would have matched the original symptom of a misfire at prolonged higher revs but this dissapeared the first time they had the injectors out without finding a problem???? also when they first tested the injectors, WHY did the original symptoms dissapear totally and somehow be replaced with the new symptom (loss in power)

Diesel additives are used in thousands of vehicles daily with no problems and just as long as the system is clean and the vehicle has been well serviced and looked after as mine had been by the previous owner (full service history etc) and he had also used a diesel additive to keep the system clean then i would not expect any major problems, the major problem that i have now got only appeared after the said diesel specialist had had the van in their workshop. And previous to that the van had the misfire for virtually 3 month with no change in symptoms.... bit of a coincidence that this new symptom should just pop up out of nowhere i think! It would take quite a bit of crap to block the fuel pump up and injectors and if this is the case then why did this not happen before it went to the diesel specialist if it was the redex? The van was actually starting to improve the week before i took it in, but with a holiday coming up i needed to be sure that it would be ok on the motorway, so decided to JUST have the injectors tested.... Bad mistake on my part. So no, i don't believe that the system was choked up with crap and was then broke up with the redex, maybe a little that affected one injector, but not to the degree that gave it the loss in power 3 months after adding it... and after it came out the diesel specialist. I would have at least expected more serious problems earlier if the system had been that dirty.

i understand what you say though, but the fuel filter that i changed had no crap in it, to sumerise, the total loss in power that affected the van is a brand new symptom which occurred 3 month after the origional misfire and the adding of the redex. If the van had covered 200,000 miles and never had a filter change i could understand, but it has been more than well looked after in the past with fuel additives also having been used to keep the system clean previously with no problems.

Baloo.

[bling69]

i put diesel redex in both my vans , in a vw transporter and a merc sprinter , a week later it blew both vans injection pumps , so maybe it has made ur pump run dry , thats when the problems occur.

[baloo]

That seems very unlucky to blow both pumps :confused: considering it took 3 months to end up with a symptom of a loss in power, a long time after the redex had been used up in my tank and just happened to coincide with the injectors being tested!

My big question all along has been if nothing was wrong with the injectors as i was told and as appears on the invoice then where did the original symptoms go when i collected the van, they only took them out, tested them and put them back in :dunno: and WHY should it now have a brand new symptom.

injectors retested and intermittent problem found on one injector, the original problem was intermittent but was cured on the original test by finding nothing wrong???? the new problem is not intermittent which does not seem to match the intermittent fault that was found with one injector on retesting them...... doesn't sort of add up does it?

Anyways, i've gone through all this before and i wouldn't want to bore everybody with the past history so far again...

i do feel though that you were very unlucky to have blown 2 fuel injection pumps and after only a week of adding diesel redex.

i suppose every story tells a different tale and no 2 incidences are alike...

[mojogoes]

So obviously i new of the old problem (went sick stubbling after i while over 2000rpm then corrected itself on tickover)...your van had........whats the new problem now i seamed to have mist this been said.

[baloo]

new problem since coming back from diesel specialist is a loss in power/no boost

[a8 tech]

1072 this is vag com but its based on the original 1551 but vw now use 5051b,but you can see boost actualand specified

[mojogoes]

I see....Baloo so the week or a couple of days before you sent your van to vw it was down on power correct! , when you started it up first thing what was ilde like....and did it smoke at all.

Does the fuel filter on your 2.5L tdi come with a temp check valve or not....sometimes these get blocked up and in some cases send bubbles to the pump causing cavitation.....can you see any smoke when your driving or accelerate away from say 30mph foot to the floor.

I must admit that i have used redex petrol cleaner before and found the car to run worse than it did before i used it , try millers additives they do work (cetane boost /sports plus etc)......i have also had/seen cases in which the dealership have used a brand new maf sensor only for the car to have the same lower power symptoms it had before.....i still think that you have a boost/vacuum leak somewhere!!!

I also wonder if they have set the actuator rod on the new turbo to the correct position/length?

[baloo]

update....

Van is back from VW with a new turbo fitted and still not running right, van is still down on power, it is better than what it was but is still way down on boost/power.

To summerise.... one new turbo fitted and problem not solved fully this is after they tested the turbo in the first few days and found nothing wrong with it... so why fit a new turbo??? Also, THEY HAVE LOST MY ORIGINAL TURBO!!!! which i had given them strict instructions to keep as i wanted to pay the surcharge and take it to be tested, seen as they had already tested it as being ok and then replaced it aprox 6 weeks later!! FUNNY HOW THINGS GO MISSING!

To answer your question mojogoes....
when the loss of power occured (after it came back form diesel specialist) it started better than it had for ages with no smoke and ticked over great, just a total lack in power.
No smoke was visible at all, it seemed like it was being starved of fuel.

I'm not sure if my fuel filter has a temperature check valve, it has the main fuel pipe and a clear return pipe, i think there is another pipe which i have read about that feeds any unused heated fuel back to the tank, but am not positive of this.

I did unscrew the drain plug in the bottom of the fuel filter yesterday and there was a gurgling noise as if air was present, i had done this before when i had no problems and did not hear this noise??

baloo

[a8 tech]

hey baloo i think its time you bought vag com and have a look at the engine management so you can post any info on here,you have learned alot about your van over the 2 months and this handy tool may be are answer to further help and exact readings of the airmass\turbo.Dont forget to check that fuel filter and if all else fails i will be able to have a look at the end of october as iam booked up with charity work till then.There may be some members near you who will hook up there vag com for you

[baloo]

Cheers Jon, i may take you up on the offer if i still have the problem by then :beerchug:

I was thinking of downloading vagcom, i forget the name of the site now but there is a free version isn't there? I was reading up on it last night where there was a tutoral page that took you through it, the basics don't seem that difficult to follow. will just need to borrow a laptop :approve:

i'll go purchase another fuel filter, that will be 3 in 3 month :aargh4: there is some diesel on top of the filter at the moment, and was going to check to see if that is just where they replaced it a couple of month back or may of had it off again since.

[DubDick]

I think diesel evaporates within a week so I would suspect that they've had the fuel lines off again recently. Not sure why you need to replace the filter again though?

The T4 does recycle the fuel back through the filter to help bleed air back to the tank and also the pre heat the filter.

Why would it need a temp check valve though?
If the temp check valve is safety feature then I'm sure it would be incorporated into the top of the fuel filter housing.

So lets forget talk of the filter, its the pump!!

Question is how???

[a8 tech]

Any joy yet baloo i have missed you

[markalan]

hi just cured a similar problem on my 1996 van i replaced all the injectors with new and hey sweet as a nut, to be fair no garage is going to commit and say your injectors are fine ,at least one will have a problem (they are in the game of repair and sell ) but still i now know iam getting max mpg hope this helps cheers

[baloo]

MOTHER OF ALL UPDATES.......

Right, first of all sorry for the BIG delay in posting on here, especially to A8 tech who has been really helpful and also everybody else who took an interest in the problems I had last year. My last post was on 16/9/2007 and after this date I wrote to VW Germany to inform them of the problems I had incurred with a said VW dealer...... new turbo fitted and charged a total of just over £1,200 but did not cure the fault.

My van was then collected by VW and taken to their technical centre at Milton Keynes, where they had it in their possession for aprox 3 weeks, in this time, the fuel pump was replaced, new injectors fitted and they also replaced the exhaust system which was damaged by the original van centre. All this work was done free of charge and I was also refunded the van centres original bill.

That’s the good news and to be honest I couldn't have been happier with the response that I received from Germany and the helpfulness that was shown at the time.

However, it is now May 2008 and after informing VW again of running issues of the vehicle back in November of last year and my vehicle being taken to another van centre on 3 occasions, where a new coolant temperature sensor was also fitted and said to be causing the problem, which was organised by VW UK, it is still not running right.

I was informed after my vehicle was test drove by this van centre that they could not replicate the problem that I had informed them of and VW UK informed me that until I could show them the problem in a road test myself then no further investigative work would be undertaken. I agreed to take a representative of VW from Milton Keynes tech dept (master tech) and also the manager of the van centre out on a road test which VW had insisted on to show them the problem. On the 2hr road test that took place it was witnessed by these 2 VW representatives that there was in fact a running problem with my vehicle and was diagnosed as possibly being the EGR valve sticking open. My vehicle was then returned to the van centre to have a new EGR fitted and I was informed that they were now sure that they had in fact cured the fault. On receiving my vehicle back I was disappointed to say the least that the problem still existed, if not quite as bad as what it was but was still noticeable, also noticeable was the fact that my vehicle was down on power from when it went to have the EGR fitted and it does seem that the fuel pump timing had been retarded to try and eliminate the problem that the vehicle had, presumably because the new EGR had not cured the fault like VW had hoped.

I was then informed again by VW in a letter that they believe the vehicle to be within VW's specs and that no further work will be carried out, this is after they witnessed the fault themselves in a road test they had insisted on! In this letter though they indicated to me that until a 2nd opinion could be shown that there was a problem then they would not undertake any further investigative work on my vehicle. My reply to VW was that I had proved there to be a fault with the running of my vehicle in a road test that THEY had insisted on and I didn't see reason why I should now have to prove the same fault exists to them again after already having done this.

Their reply to my letter simply states again, that they are not prepared to investigate the problem further, also stating that seen as I have not agreed to their offer of having a 2nd opinion which would have been organised and paid for by themselves, even though in my letter I offered to take them out on a further road test which was what they had insisted on first time round, and which had proved there to be a problem, then they would not investigate this any further and will also not enter into any further correspondence!

Is this VW's normal practise to deny a problem exists, even after having witnessed it for themselves?

By the way, the running problem that the vehicle is suffering from is rough running at prolonged higher revs, and I am only talking of running the vehicle at between 2500 and 3000rpm. If allowed to tickover for 5 minutes after the rough running has appeared then the van runs perfectly for a short while (a few mile) also I have now noticed that if after starting I then rev the engine a few times (up to about 3000rpm) then the van runs well, if it is not driven at higher revs for any prolonged period of time.

This to me is a fuelling problem, even the master tech on the road test stated that he felt it was the EGR sticking open and weakening the fuel mixture at higher revs. They now though have tried to discount the road test where it was proved that there was a problem, even fitting a new EGR after witnessing the problem, but now say there is no problem!!!?

This whole saga has now been going on since the 19 July of last year (2007) when VW first touched my vehicle, which is quite unbelievable.

In my last letter to VW numerous questions that I had asked have been totally ignored as regards the events of the road test they insisted on and the fault that they witnessed, and also another item that I pointed out to them as regards the clutch now biting further up the pedal and showing signs of excessive wear after being returned from the van centre previous to the EGR being fitted.

I just thought I would update this thread and inform everybody who has been of help on here concerning my problems, obviously it is still ongoing at present, but if VW are looking, it would be interesting to know why, after you have witnessed the problem, you are now trying to say that no further investigative work will take place to cure this problem?

If anybody has any idea what may be causing this running issue then I would like to hear from you, as VW don't seem to want to find a cure at this time.

Thanks for reading, and sure to say that I will not be buying another VW on the evidence of the last near 12 months! I was impressed with their attitude last September when I believed that the problems that I had encountered would finally be rectified, but it is now virtually another 8 month on and a different story.

All I have ever asked is for my vehicle to be running as it should, I would have thought that VW themselves could in fact have obliged and reinstated my confidence in them.

Only time will tell.

Baloo.

[a8 tech]

Baloo,why didnt they re road test the van with you after the egr replacement to confirm the results,also they could have just bypassed the egr and re road tested to eliminate.Very odd,anyway i suppose this means only one or two things left and i suspect there may be a mechanical issue within the engine or weak injector as everything associated with the fuel/air side has been replaced including the ecu.I also would hae expected vw to have connected 5051b diagnostic whilst the road test was under taken to record via measured values the timming and fuel temp/coolant temp as wellas maf readings and possible dynamic timing to forward to relevant diesel specialist(she a lady)at vw tsc.I wonder if this fault could be recreated via a rolling road test.Sounds like your on your own with this so i would bypass the egr and try it as theres nothing to loose and if you rember the Vagcom adjustment for incresing the fuel and reducing egr duty cycle also.

[baloo]

Hi A8 tech,

First of all a small update on what has actually been replaced:

Turbo
fuel pump
injectors (so i am informed)
complete exhaust and cat
fuel pipes
coolant temp sensor
MAF
breather pipes
fuel filter x3
air filter
EGR

Fuel pipes were fitted after the vehicle was returned to me and after the new pump and injectors were fitted.

The ECU is the original, it was only removed to be tested with a donor ecu then mine was replaced - so i was informed by the original van centre who first worked on my vehicle.

I believe they did not re-road test my vehicle with me after the EGR was fitted because they knew there still to be a problem.

I have asked the question as regards the injectors maybe being at fault or at least one, and i get the same answers - the vehicle is within VW specs (which it can't be, as there is still this running issue which they have witnessed!)

As regards an actual engine problem, i have questioned them on this, as they informed me last October that the master tech working on my vehicle was at one point considering taking the head off for inspection - this they never did, but i do wonder why i was informed of this, they were obviously still struggling to fully diagnose the problem, this was after they had already fitted a new pump and were still not satisfied. Could there be a problem with the head gasket? i have asked them this question but again I have failed to receive an answer.

As for not connecting up to VAGCOM during the road test then your guess is as good as mine, when you mention it, it seems the obvious thing to do if you are trying to locate the problem. this is what makes me believe they know what the problem is but for whatever reason are reluctant to admit there is a problem. They witnessed the problem after insisting that no further work would be carried out until i could show them in a road test the actual fault, which i did, and then after fitting a new EGR, came back with the same story - the vehicle is within VW's specs and until they receive information stating differently they will not investigate the problem any further...... this was after witnessing the fault, fitting a new EGR which did not cure the fault, and then saying THEY would organise a 2nd opinion! Aparently now, the road test is no longer good enough evidence of a fault existing, yet they insisted on this road test originally and witnessed the fault for themselves! I have offered to take them out on a further road test, for which i have not received a reply, other than the standard (within VW's specs answer) and an added, no further correspondence will be entered into! They obviously have a very short memory as regards the problems they witnessed on the road test, and obviously are not keen on another road test as they know there is a fault which i will show them again.

As for bypassing the EGR, i will not be touching the engine at this point, VW know there is a problem and i will not be attempting any work myself. As for advancing the fuel mixture then i don't have VAGCOM and again i am not in a position to start interfering with the work that VW have done up till now.

As regards rolling road showing this fault then i haven't got a clue, I would think it could, because if you drive the vehicle at prolonged higher revs then the fault occurs.

It is funny how if allowed to tickover after it has run rough then it runs ok for a while, the same as when i rev the engine 2 or 3 times first thing on start up and the van then runs better (if you don't increase the revs for a prolonged time). I still think it is fuel starvation at prolonged higher revs, whether this be through actual fuel blockage or running lean after being driven at higher revs. It does seem like it is not getting sufficient fuel at higher revs.

My last question is, could it be head gasket and compression down in one pot? but if this was the case then why does allowing it to tick over for 5 minutes cure the problem? or like i've said a few good revs in the morning and the van runs smoother.

I think you once said that there is light at the end of the tunnel, and someone recently said this to me, but i do believe it might be the train!

Baloo.

[DarrenUK]

Baloo (or anyone else involved)

Just read this post and it appears that you got your original symptoms back and lost the low power?

When did this occur ?

Any further updates to this storey?

[baloo]

Baloo (or anyone else involved)

Just read this post and it appears that you got your original symptoms back and lost the low power?

When did this occur ?

Any further updates to this storey?

In answer to your question, the original problem was a definate misfire where the van would run on 4 cylinders, this is not the case now where the symptoms are different. The van now runs rough and shows a power loss if driven above 2000rpm for any prolonged time, like i have said, if you rev the engine a few times when first started and then keep the revs below 2000rpm then the van runs better, but once you start driving above 2000rpm the problem returns. If allowed to tickover for 5 minutes then the van will run smooth again and power is also improved, this is short lived though if you continue to drive above 2000rpm.


VW seem to think the above symptoms are within their specifications!!


VW replaced the EGR after witnessing the problem in a road test with me but this has failed to cure the problem. Basically admitting the problem exists on the roadtest then denying a problem exists after fitting a new EGR which DID NOT cure the fault!

They now state they will not enter into any further correspondence!

Would you buy a VW or any make of vehicle knowing that the manufacterer seems incapable of curing a fault and then wants to walk away from the problem with no explananation as to why the above symptoms exist?

Baloo

[DarrenUK]

Yes slack behaviour from VW. I can see how this is disappointing and frustrating for you. The initial poor service (I'm sure there is a good reason that many people refer to them as main ********)- followed by VW appearing to want to compensate both financially and by bringing in an expert to sort the problem and then just dropping it all and denying there is a problem....

An interesting read - I'm sure it would make good TV?

If I was in your position I would be connecting up the van to VAG-COM and logging all engine variables in a series of test drives where the fault happens to try and shine some light on your problem.

That and/or threatening VW with giving your issues a fair deal more publicity (TV, popular motoring/automotive websites etc.)

[NZT4]

hi, just found this and may be able to offer a different angle, could the fuel tank vent possibly be blocked? i do not know the system at all, but on my model aircraft, if the tank is not vented correctly after some time at high power a negative pressure would develop in the tank causing feed problems to the carb.. you might be able to easily test for this by provoking the symptoms then quickly taking the fuel cap off and listening for the tank taking a big gulp of air. it is possible the vent is only partially blocked and allowing the tank to equalize when you leave the van idling for some time thus "resetting" the problem.
a bit outside the square i know, but it seems you have tried everything and still no joy..
steve

[Brian Considine]

I too have just stumbled on this thread & would agree with the last poster that fuel tank venting could be worth looking at - the symtoms suggest that it could be fuel starvation caused by a vacuum building up in the tank due to lack of venting.

A quick test would be to run the vehicle with about half a tankful on a straightish road* very hard without the fuel filler cap)- if the vehicle runs fine - there's the problem - worth a try ?

* Make sure you don't spill any fule onto the road.

[Curnow]

G'Day Baloo,
Read your thread from start to end last night. Did you ever get to the bottom of the problem?
Did they try jacking up the radiator cap and replace the rest of the van:D

Cheers
Dennis