Rough on idle/drive 1.9TFI 150,

[RickT]

Heres a message from Boraboy via PM --

can you guys help out

Sounds like it could be a MAF issue.. however there nothing been logged in VAG-COM?

Could it be a turbo issue mayme??

Cheers

RickT...


(See PM below)





Hi Rick,

Having read a few posts, you seem to be quite knowledgable and wondered if I could pick your brains a sec!

Ive got a 1.9Tdi 150bhp Bora (03 reg, 60k on clock) and have noticed recently that the car "kangroos" a bit when I try and maintain a steady speed, or begin to accelerate. I cant really describe what the problems is, but its as if the engine is calling for diesel momentarily and then appears to receive it and the cars ok again!

I have taken it to the mechanics and they put it on the diagnostics machine, but no fault codes were registered. They changed the fuel filter and it appeared to make the car run a bit better, but it still has the above problem. They told me the fuel lines were not blocked so were stumped!

Also, in addition to the above issue, when the vehicle is idle, it has little "blips" and the rev counter moves from about 800 to a 1000 revs every few seconds. This has started at the same time as the other issue.

Probably baffled you by now, so thanks for your time. Its going back to the mechanic on Tuesday so they can rip me off a bit more!!!

Thanks
Mark
http://www.vwaudiforum.co.uk/forum/images/statusicon/user_offline.gif

[Eshrules]

id probably go with the MAF to start with Rick, mainly because its a fairly cheap part to replace... IMO, if it was the turbo, i dont think that would affect the idle of the car... would also think if the turbo/EGR/turbo vines were faulty, it would cause the car to go into limp mode... ecu codes etc etc as you know.

the other thing thats a bit confusing is that if it IS the MAF, why werent any fault codes read? i wouldnt have thought replacing a fuel filter would have done a lot tbh, it sounds as though this garage may be giving him the run around?

one more thing... he says they've had it on a diagnostic machine.... was it vag com though, or was it a crappy generic code reader? if its only generic, it wont pick up vag specific codes will it?

[Boraboy]

Hi all,

I spoke to the mechanics today and they said that they have a BOSCH KTS system reader as the cars run on that program. (All gobbledygook to me).... but its going back tomorrow and they said they will look at the MAF as this has not registered on the system before with other VW's.

Does this sound sensible or are they just trying to pull a fast one. (Considering the mechanics have a very good reputation in Sandhurst) They are called Vulcan Motors....and they do have a web site, but not sure if I am allowed to put it on here?

Thanks again for your help....
Mark:1zhelp:

[Eshrules]

hmm, little confused about the bosch KTS thing, alls i know is that to read codes and monitor the sensors, you should be using VAG COM, not sure about what they said about the MAF? could you explain a little further? be very wary, you paid for a diagnostic once, they should do the 2nd free of charge as the origional fault wasn't cured.

[Boraboy]

They said that the majority of cars they repair are VW's, Audi, Porsche, BMW and they are all put on the BOSCH KTS diagnostic system. The tech said that if the MAF was not working it would not show up on diagnostic machine. They obviously dont use VAG COM..... so they are going to run a test tomorrow by taking the MAF off (if thats possible) and trying the car out.

[Eshrules]

LOL so what they're saying is this bosch VTS isnt the same as VAG COM. they obviously dont know what they are dealing with, as i am certain that a fault on the MAF WOULD log a fault code, or could be picked up through logging. every sensor communicates with the ECU and if im right in thinking, each sensor has its own set of fault codes, to log in the ECU to show certain faults. if they just take the MAF off and run the car, i am pretty sure it will run like a bag of cack? i dont know what they expect to achieve with running a car without a MAF sensor. its like taking the turbo off a tdi and expecting to run it properly. i have to admit, if this was me m8, id be going somewhere else, it sounds like they are taking the right royal Pi$$, could just be me though?

[Boraboy]

Appreciate your help..... im just trying to save myself £100 an hour labour at VW dealership!

Looks like I might have to go and get them to put it on their diagnostic machine and see what it says!

[Eshrules]

Appreciate your help..... im just trying to save myself £100 an hour labour at VW dealership!

Looks like I might have to go and get them to put it on their diagnostic machine and see what it says!

as do we all! give us an idea as to your location, lots of people have vagcom nowadays, if theres someone near to you, im pretty confident they would help you out! btw VW charge approx £40/45 for a VAG com diagnositc

[Boraboy]

I live in Camberley, Surrey - yes thats "dannn Saffffff" for those of you from the north of england! LOL

[Eshrules]

I live in Camberley, Surrey - yes thats "dannn Saffffff" for those of you from the north of england! LOL

may be worth seeing if you can get someone to read your codes for you?

[VW Techniker]

The Bosch KTS is a powerful bit of kit and until I purchased my VAS 5052 (Which nothing comes even close too, by the way...) I would rather use it over VAG-COM, as it never let me down. Don't get me wrong VAG-COM is a good bit of software, I'm not knocking it, I do have the professional kit myself, as I work with nothing other than VW's... BUT... It's got it faults.!

Also a incorrectly operating MAF does not often generate a fault code.

[VW Techniker]

OK I FEEL BAD NOW... I'm not getting at anybody who thinks VAG-COM is the nuts; to a non professional it more than likely is...

In 1995 I purchased a VAG 1551 and I still have and use it in my workshop today, but it's far too big, kind of like having a small caravan toilet on your lap, but it still does it's job very well. After owning it for 16 years, I now know the capabilities of the machine like I know the back of my hand.

VAG-COM is also very good, but, it's a VAG 1551/2, nothing more, nothing less... I have found that it offers no more capabilities than the origional 1995 version of the VAG machine.

I have tryed out a lot of the better quality aftermarket diagnostic testers over the years and... (All the Good technicians are going to hate me for saying this... So, SORRY IN ADVANCE) the machine with the most likeliness to the VAG 1551 is in fact the Snap On Scanner; it's like using the real thing.

There are some very good diagnostic testers on the market, and thousands of S*&T ones, but OE is the way forward.

Very soon the "Fault Code" will be obsolete and so it should be, because it points too many people, including technicians, in the wrong direction. A fault code is only generated by a systematic series of events and usually not actually trigered by the sensor that has flagged the fault.

VAG-COM is a well written software, but it's old technology.

I sincerely hope I have not offended anybody, I am simply sharing my knowlege with you all and perhaps preparing you for the future.

[Boraboy]

I went back to the mechanics again today....still cannot find what is wrong with the car. They are 60% sure it is the MAS but do not want to purchase a part that costs £70 in case it doesnt work. As stated earlier, re-read the car and it has no fault codes. Im definately not making this up...my car is not driving right!

Fair enough, they didnt charge me for looking into it again for me, so I have had to bow down and booked it into VW Camberley tomorrow. Cant believe they are going to charge me £48 for 30 mins labour in order to put the car on their own machine, which will no doubt tell me the exact same thing!

I think I might get rid of the motor as its spoiling my appreciation of VW's.

:( :( :( :( :( :confused: :confused: :confused: :confused:

[Eshrules]

OK I FEEL BAD NOW... I'm not getting at anybody who thinks VAG-COM is the nuts; to a non professional it more than likely is...

In 1995 I purchased a VAG 1551 and I still have and use it in my workshop today, but it's far too big, kind of like having a small caravan toilet on your lap, but it still does it's job very well. After owning it for 16 years, I now know the capabilities of the machine like I know the back of my hand.

VAG-COM is also very good, but, it's a VAG 1551/2, nothing more, nothing less... I have found that it offers no more capabilities than the origional 1995 version of the VAG machine.

I have tryed out a lot of the better quality aftermarket diagnostic testers over the years and... (All the Good technicians are going to hate me for saying this... So, SORRY IN ADVANCE) the machine with the most likeliness to the VAG 1551 is in fact the Snap On Scanner; it's like using the real thing.

There are some very good diagnostic testers on the market, and thousands of S*&T ones, but OE is the way forward.

Very soon the "Fault Code" will be obsolete and so it should be, because it points too many people, including technicians, in the wrong direction. A fault code is only generated by a systematic series of events and usually not actually trigered by the sensor that has flagged the fault.

VAG-COM is a well written software, but it's old technology.

I sincerely hope I have not offended anybody, I am simply sharing my knowlege with you all and perhaps preparing you for the future.

LOL i dont think offence can be taken when you are simply offereing your advice, as i would always say to people, it is welcomed, the more broad advice you get, the better informed you become, all part of learning :)

[frakkafield]

The MAF is something I'm thinking of replacing on my car, Info I have gathered is as follows; MAF's deteriorate over time, expect about three years or sixty thousand miles, As they are on their way out they give faulty readings which causes funny things to happen with the fuelling and creates flat spots, if you are replacing it, replace it with a bosch one, the cheaper alternatives don't work, i.e worse than a deteriorated flat spot,

MAF's don't generate fault codes, the reason for this apparently being that the ecu has nothing to compare the readout against, the ecu has no reason to think that anything is amiss

check this guy's site for info

http://45zs.info/Mafam/MAFQAS.htm

I ran my car withaout the MAF unit, and while all the power was not there as usually is, it was all a lot smoother, I mean an awful lot.

By my understanding it just stops the variable vane part from working and standardises the fueling.
If you can source a bosch unit for seventy quit, I think you'll probably find it is money well spent.

[Eshrules]

The MAF is something I'm thinking of replacing on my car, Info I have gathered is as follows; MAF's deteriorate over time, expect about three years or sixty thousand miles, As they are on their way out they give faulty readings which causes funny things to happen with the fuelling and creates flat spots, if you are replacing it, replace it with a bosch one, the cheaper alternatives don't work, i.e worse than a deteriorated flat spot,

MAF's don't generate fault codes, the reason for this apparently being that the ecu has nothing to compare the readout against, the ecu has no reason to think that anything is amiss

check this guy's site for info

http://45zs.info/Mafam/MAFQAS.htm

I ran my car withaout the MAF unit, and while all the power was not there as usually is, it was all a lot smoother, I mean an awful lot.

By my understanding it just stops the variable vane part from working and standardises the fueling.
If you can source a bosch unit for seventy quit, I think you'll probably find it is money well spent.

as above really :D quite a good summary of the MAF issue, it would appear as you have said, the MAF is more or less a wear and tear item nowadays!

[frakkafield]

Just a quick subnote,
Last night I cleaned my MAF sensor, using an electrical solvent (i.e used by sparkies for cleaning circuit boards and the like) to clean my MAF sensor, the car is beyond recognition, smooth from startup, starts pulling a lot stronger from 1500rpm and a lot less reek in the rear view,

Surprising bonus, an increase in economy, from 40 ish for general running to and from work to 48, that's a big differance, wish I'd got round to it sooner.

Engine was always smooth, but now it's a whole lot smoother, I would reccomend checking and cleaning to anyone who thinks thier motor isn't running just quite right.
The security screws can be removed with a decent pair of mole grips, but remember not to touch th element, use an aerosaul spray theat will just run away, and look for one that doesn't leave a residue.

Enjoy

[Eshrules]

Just a quick subnote,
Last night I cleaned my MAF sensor, using an electrical solvent (i.e used by sparkies for cleaning circuit boards and the like) to clean my MAF sensor, the car is beyond recognition, smooth from startup, starts pulling a lot stronger from 1500rpm and a lot less reek in the rear view,

Surprising bonus, an increase in economy, from 40 ish for general running to and from work to 48, that's a big differance, wish I'd got round to it sooner.

Engine was always smooth, but now it's a whole lot smoother, I would reccomend checking and cleaning to anyone who thinks thier motor isn't running just quite right.
The security screws can be removed with a decent pair of mole grips, but remember not to touch th element, use an aerosaul spray theat will just run away, and look for one that doesn't leave a residue.

Enjoy

a helpful tip, my car is showing a little 'hesitancy' in its movement sometimes, ie around 2k revs it 'lerches' untill a lot more gas is given and then seems to go fine, think this may be down to the MAF? its had a recon turbo so doubt it's that, what solvent did you use and where did you get it from?

[frakkafield]

I used an RS 180-825 spray that we use at work for cleaning mechanical seals, it's advertised as a computer solvent, I've never seen it in the shops. Anything that will vapourise and not leave a residue. Look for any aerosaul cleaner and read the tin, if it says something like 'lubricating' or 'corrosion protection' then it aint going to help.
You could always ask your local garage what they might use, if they're any good they'll have a good idea.


Let me know how you get on, will be very intarested to hear if your response is as positive as mine, here's hoping

Regards
Craig
P.S thanks for the vote of confidence earlier (post 16)

[frakkafield]

Just been browsing the net, a lot of people suggest brake cleaner or carb cleaner, which are more readily available options, a fast evaporating solvent. Hope that helps.

[Eshrules]

Just been browsing the net, a lot of people suggest brake cleaner or carb cleaner, which are more readily available options, a fast evaporating solvent. Hope that helps.


i already have some carb cleaner at home, but thought this may be a little too abrasive for MAF? i've heard it can damage the sensor?

i may need a little help LOL in locating the MAF way i look at it, as long as i dont do any damage in the process LOL is that, its free to try and could help the car run better. im almost certain its something to do with the maf as mines had a recon turbo as said and all new turbo/air hoses, not sure what else could cause this 'stuttering' through the rev range?

[frakkafield]

It's easily located, Find your air fillter, the box is mounted in two halves as it were, i.e top and bottom, top half feeds to your turbo, the pipe/hose out of the top half is where the MAF will be located, it's the first thing the filtered air passes over, by my understanding, it is used on the vag diesel engines, to control the vanes on the turbo as well as the fuelling, do a search on ebay and you'll see what the component looks like.

My understanding of how the MAF works is thus: A section of resistor wire is mounted by the air intake, this the ECU keeps at around 200 deg c, as you drive more air passes over the element thus cooling it, a sort of a windchill effect. The ECU responds by increasing the current to maintain the temperature, the amount of increase needed is measured to determine how much air is going in, and thus fuelling etc is adjusted accordingly.

Imagine this same hot bit of wire, no air filter is perfect and over time bits of pollen and polutants get past, coming into contact with this hot piece of wire they 'burn' or carbonise, therefore this piece of wire is insulated, so doesn't suffer as much from windchill. Therefore giving false readings to the ECU which in turn gives wrong fuelling to the engine.

Although it's a fine bit of wire which could easily be broken, i don't think a bit of chemical is likely to hurt it, still, best to err on the side of caution.

What you're looking for is a chemical with a strong cleaning action that will evaporate quickly.

I wouldn't try this with the engine running, or even the ignition primed, could start a fire.

What you're wanting to achieve is removal of carbon deposits, which is what a carb cleaner is designed for.


if you're not too confident, get somebody else to do it, you'll probably find a garage boy who will do it as a homer for a fiver

Good luck

[Boraboy]

Hi all,

Just had the MAF replaced on the car and so far it seems to be a lot better....the real test will be on the M3 tonight on the way to work.....

Wish me luck! (or its been £150 down the pan)

Oh yeah, Many Many Thanks for your all your help re the above!
Mark

[Eshrules]

It's easily located, Find your air fillter, the box is mounted in two halves as it were, i.e top and bottom, top half feeds to your turbo, the pipe/hose out of the top half is where the MAF will be located, it's the first thing the filtered air passes over, by my understanding, it is used on the vag diesel engines, to control the vanes on the turbo as well as the fuelling, do a search on ebay and you'll see what the component looks like.

My understanding of how the MAF works is thus: A section of resistor wire is mounted by the air intake, this the ECU keeps at around 200 deg c, as you drive more air passes over the element thus cooling it, a sort of a windchill effect. The ECU responds by increasing the current to maintain the temperature, the amount of increase needed is measured to determine how much air is going in, and thus fuelling etc is adjusted accordingly.

Imagine this same hot bit of wire, no air filter is perfect and over time bits of pollen and polutants get past, coming into contact with this hot piece of wire they 'burn' or carbonise, therefore this piece of wire is insulated, so doesn't suffer as much from windchill. Therefore giving false readings to the ECU which in turn gives wrong fuelling to the engine.

Although it's a fine bit of wire which could easily be broken, i don't think a bit of chemical is likely to hurt it, still, best to err on the side of caution.

What you're looking for is a chemical with a strong cleaning action that will evaporate quickly.

I wouldn't try this with the engine running, or even the ignition primed, could start a fire.

What you're wanting to achieve is removal of carbon deposits, which is what a carb cleaner is designed for.


if you're not too confident, get somebody else to do it, you'll probably find a garage boy who will do it as a homer for a fiver

Good luck

took the MAF off, took one look and put it back, it was replaced when the recon turbo was put on. all hoses for the turbo etc were renewed, so what could be casuing this 'stuttering' in the rev ranges ? im now officially stumped! :zx11:

[Boraboy]

Just a quick update.......

I had the MAF changed and the car is now officially better than what it was when I bought it.....

Thanks to everyone who gave advice and shared their knowledge...

Now for the ICE install....hahahaha:biglaugh:

[frakkafield]

Was tha AF sensor wire shiny clean?

[Eshrules]

Was tha AF sensor wire shiny clean?

your guna take the micky now ent ya, as you look at the maf , there was a band that looked like a wire, it was black, but looked new if you get me lol, is this the carbon build up that i was looking at then, my brothers friend who knows 'some' about these engines, said it was a new maf, an argument ensued about that as i didnt think it was but didnt want to clean it with carb cleaner if it was new??

[frakkafield]

Well it's up to you, it's probably the most likley cause of the symptoms you described, the other things to check are the air and fuel filter, if you know somebody with the same car you can try swapping to see if there is a differance.

What you've described sounds like how mine looked.

Do you by any chance have an aftermarket air filter? The oil from them has been known to cause a carbon build up.

I hope you get it sorted, these cars are such a pleasure to drive when their working right.

Why don't you call the garage that did the turbo swap, they should be able to tell you if they changed the MAF.

[Eshrules]

Well it's up to you, it's probably the most likley cause of the symptoms you described, the other things to check are the air and fuel filter, if you know somebody with the same car you can try swapping to see if there is a differance.

What you've described sounds like how mine looked.

Do you by any chance have an aftermarket air filter? The oil from them has been known to cause a carbon build up.

I hope you get it sorted, these cars are such a pleasure to drive when their working right.

Why don't you call the garage that did the turbo swap, they should be able to tell you if they changed the MAF.

i've had a quick look at the air filter, its like new, which means it was changed around 3k ago when i got the car. nope, i dont have an aftermarket air filter, i may get shot for saying this but i dont believe in them, especially on diesels, i honestly dont see the point for what its worth.

im up at the friends garage tomorrow so ill get the MAF off and give it a clean with the carb cleaner, i cant see it doing it any harm.

as for the dealer.... they got a mobile mechanic to replace the turbo, only as part of a trading standards investigation, its complicated but basically the only work im missing proof of is the MAF sensor replacement, i dont think they did IMO.

ill get the carb cleaner on the MAF tomorrow and update you. thanks for all the help :biglaugh: