Misfiring Vw Golf Mk4 Help!

Hi I was wondering if anyone could help I have had my mk golf 1999 auto AEH for about 4 months now and have been have a misfiring problem with it. I have had a mechanis look at it he advisded me to change plugs lead and coil I did this and the car was running fine for a about a day then started to misfire again, I then had a diognostic done and it came up with hall senor no signal please could anyone advise me on what the hall sensor does and wheather it will sort my misfire problem out, it just seems to be one thing after the other if anyone can help I would really be grateful.


Thanks

Im having difficulties with my car too..it seems to misfire, the revs move up and down, however they do become stable sometimes, it is so annoying though..what could the probem be???

i've been reading up on various articles, theres so many suggestions, the most popular one(s) being:
~ coil pack
~ spark plugs
~ egr valve
~....etc

How would you know which one is to be replaced??
It costs an arm and a leg to get all of them changed, especially when labour cost more than the parts sometimes, theres no point tryin trial and error unless uv got money pourin outta yo backside..

I hope someone can help..would really appreciate it.

Cheerz (",)

And the car is a Golf 4 what?

its a golf mk4 1.8 gti turbo (registered 2000-X plate)

It would be, right on the change point of engines. What is your engine code AGU, ARZ or AUM?

Hiya Crasher dude, the engine code is AUM.
Cheerz

Well the first thing I am going to suggest is the usual fault code read, print and clear and then re-read to see if any codes re-appear immediately and if some do, they can be dealt with. If a faulty coolant temperature sender comes up, I suggest you have it replaced. Whilst the car is at the garage having the fault codes read, I suggest you ask for the throttle body to be removed and cleaned, then the ECU adaptations cleared and finally the ECU re-adapted to the throttle body and if the garage knows how to do it, the emissions system checked by manually generating what is known as the “readiness code”. Take the car away and see how it drives for a week or so and then go back for a re-read of the codes at which point any further problems you have been having should have generated a fault code which can be compared against the original read to see if it is a reoccurring code. During this period between reads it is vitally important that the engine is not played about with and that nothing in the engine bay is disconnected with the ignition on or the engine running. The AUM engine management system can accurately pin point a misfiring cylinder and therefore a faulty coil pack but from what you are describing I doubt if you have a failed coil pack as these just fail and that is it, they never work again.

hi, i also have a Mk4 with an AUM engine experiencing the same faults!!! sometimes the car works without showing any symptoms but other times it suffers from erratic idling etc... took it to a mate at VW and got it diagnosed. it was recording misfires on all 4 cylinders. after looking about the engine, he found 2 breather pipes were leaking so i had them replaced at 30 quid a pop. this seemed to do the trick for about a week, now were bak 2 square 1. like you say trial and error aint cheap! when i was connected to the diagnostics at VW, an error came up stating that the DumpValve had mechanically malfunctioned. I am now thinking of replacing this part. i have found a standard replacement for 22 quid. this may or may not be the problem that you are also experiencing. apparantly faulty or blocked breathers can cause the symptoms that you are stating so idd check all the pipes n tubes are in good nick.
if you solve ur mystery it would be nice to know how!

If the code you got was 00575 and was interpreted by VAG-COM as DV failure (Diverter Valve, not Dump Valve, this is not a Chav car), this is usually wrong and more often than not is just a dirty throttle body. The DV is easy to check, take off the vacuum pipe on top and attach another piece of 3-mm vacuum pipe, suck on the pipe and if you can suck air through it, it is faulty.

yeah i got the throttle body cleaned when i changed the breathers. just kept foot down on the accelerator n my mate cleaned it with a rag. This sufficient? havnt had chance to check the diverter valve as i aint got a jubilee clip to replace the crimp currently in place. hope to do that soon. whats boggling me is that the car only seems to misfire when the engines cold at startup. this is not the case all of the time tho, like this morning, my car was frozen cos it was soo cold but it started fine streight away! i took it for a long 2 hour drive to manchester on weekend and it was fine all of the way there and back. it had a lil niggle when i started it up to come back but on the motorways it was fine! getting average mpg too, 31 mpg on the motorway, so i dont think its misfiring when im driving and not noticing.
oh since my last post, ive changed my plugs. Stil not improved things, althogh i didnt believe this would anyways, i just didnt know when they were last changed so...

No that is totally insufficient. It needs to be removed and carefully cleaned internally with a stiff nylon brush and erosol carb cleaner. After, it MUST be readapted to the ECU in Basic Settings 04, main group 060.

Quote:

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Originally Posted by Crasher

No that is totally insufficient. It needs to be removed and carefully cleaned internally with a stiff nylon brush and erosol carb cleaner. After, it MUST be readapted to the ECU in Basic Settings 04, main group 060.

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oh so this could still be the problem? ill give it another go if you reccomend this. i know that it was definately readapted using the vagcom. what does this do though? if i were to clean it at home would i be able to drive it to the garage to get it readapted? or would it cause it damage?

Cleaning it yourself and then driving it to the garage is fine, it may idle high. The re-matching moves the TB through a series of steps from closed to maximum movement available by the stepper motor and steps in between. At each of these points a voltage is returned to the ECU so the ECU then knows where to position the TB for idle control. If the TB butterfly and/or seat are dirty, the butterfly will not shut and will allow air part on the overrun which the ECU interprets as a failed DV.

Quote:

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Originally Posted by Crasher

Cleaning it yourself and then driving it to the garage is fine, it may idle high. The re-matching moves the TB through a series of steps from closed to maximum movement available by the stepper motor and steps in between. At each of these points a voltage is returned to the ECU so the ECU then knows where to position the TB for idle control. If the TB butterfly and/or seat are dirty, the butterfly will not shut and will allow air part on the overrun which the ECU interprets as a failed DV.

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which is the problem it has been logging. thanks for that Crasher, ill give it a go when i get the chance. you got any other warnings if im doing this for the first time?

It has to be the easiest TB of all to remove and clean.

long time no post. ive bin in and outta hospital and so aint had chance to take the TB off as of yet. What i have managed is to is get a hold of the faults that vagcom has diagnosed. these shed any light as to the cause?


17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction

P1200 - 35-00 -

16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411

16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300

16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297

16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301

16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303

17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548

17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction

P1200 - 35-00 -


Faulty diverter valve (common), faulty solenoid (rare) or dirty throttle body, the most common reason.

16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411


Ignore this for now, usually the SAI inlet valve on the side of the head.

16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300


One or more coil packs

16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304
Number 4 coil pack

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297

Dirty throttle body

16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301


Number 1 coil pack

16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303


Number 3 coil pack

17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548

Possibly a faulty N75 valve but usually just someone disconnecting it with the engine running/ignition on. Clear it and see if it comes back.

thanks crasher, ill get that TB cleaned asap!!!

And then reset in Basic Adjustments, group 060.

Finally got round to removing my TB yesterday. heres a few pics of how dirty it was along with the manifold to which it attatches to;
http://s270.photobucket.com/albums/j...current=TB.jpghttp://s270.photobucket.com/albums/j...urrent=TB2.jpg
ive since cleaned it and replaced but not had a chance to vagcom it.
what i did notice was that the butterfly valve does not seat completely shut. is this normal to allow a small amount of air to be supplied or should this valve be completely shut with the ignition on?
i also cleaned what looks like a sensor with the carb cleaner.
http://s270.photobucket.com/albums/j...ent=Sensor.jpg
the car took a lil encouragement to start due to the amount of carb cleaner i used and sprayed through the manifold but it seems to idle fine. however, i have already experienced misfiring having driven it today. this happened as i was driving soon after setting off :zx11: so i pulled up, restarted the engine and all seemed fine?!?
im wondering what to do next?

looks like my photos didnt work so heres the links

http://s270.photobucket.com/albums/j...current=TB.jpg

http://s270.photobucket.com/albums/j...urrent=TB2.jpg

http://s270.photobucket.com/albums/j...ent=Sensor.jpg

What you cleaned is the air inlet temp sender. The rest position of the TB motor is set in basic settings 04, sub group 060 and the misfire is going to be a coil pack or three looking at those previous codes. Have you had the plugs out recentley?

yeah i've changed the plugs with no luck! before i had the DTCs removed for the first time it said that there were misfires on all 4 cylinders, this led me 2 believe that the coil packs were fine (coincidental that all 4 stop working at the same time). surely the coil packs would fail full stop and not be intermittent on every 5th or 6th (approximate i.e. once every 2 days) ignition cycle? what sends the signals to the coil packs to fire? is it the ecu? could this be to blame?
is there any test i could do to check that there are no air leaks in the breather system other than disconecting all of the pipes and inspecting each 1? i did find 2 pipes had slits in them and i replaced them.
it just seems strange that the car only does it when the engine is first started or within the first 2 minutes of driving (only happened 3 times in a month or so) and it goes away if you take the revs up to 2000-3000 for 15-30 seconds. when the car has done it whilst moving, i have simply pulled over, turned the ignition off for 10 secs or so, started her up again and shes fine :confused:
i have also used a bottle of 'Redex' in a tank of fuel but this didnt seem to do much either :( is it worth changing the fuel filter or would this bring up its own fault in diagnostics?
i dont think that the problem is getting any worse or more frequent which is a good thing! i think it was worse before i changed the damaged breather, or maybe i just didnt know how to go about it when it was misfiring like i do now.

i must say thanks for your time and thoughts crasher!

Fit four new coil packs, it is removing them that makes them fail. We use the proper VW puller and silicone grease on the plugs and they still stick, which causes stress on the CP and results in failure.

i thort that you mentioned earlier in a post that if a coil pack fails, it never works again? some days the car is trouble free!?!:confused:

Good point, you read too much! I have had them play games before they go but when they stop working, that is the end of them.

Quote:

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Originally Posted by Crasher

17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction

P1200 - 35-00 -


Faulty diverter valve (common), faulty solenoid (rare) or dirty throttle body, the most common reason.

16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411


Ignore this for now, usually the SAI inlet valve on the side of the head.



17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297

Dirty throttle body



17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548

Possibly a faulty N75 valve but usually just someone disconnecting it with the engine running/ignition on. Clear it and see if it comes back.

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What do you think i should try next? how much suction do you need to need to give the Diverter Valve to check that it is still working? i couldnt find a hose that would fit it so i removed all 3 pipes and tried sucking through the small one. it seemed air tight to me! couldf it still be this? Whats the N75 valve?

What fault codes are you getting now?

Still aint managed to get them erased. Hopefully that'll be some time this week, along with re-adapting the TB. Think i'll get that done then repost em.

since ive only got a dumb copy of vagcom i can only read errors. I have just run the software again and it has found another few :( can anybody shed any light as to what the problem could be to cause one of these...
Obviously the previous codes are still present but there are a few new ones...

17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction : P1200
16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411
16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300
16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304
17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297
16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301
16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303
17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548
16686 - Cylinder #2 - Misfire Detected
or Cylinder 2 Misfire Detected : P0302
16705 - Engine Speed Sensor (G28): Implausible Signal : P0321
16497 - IAT Sensor - Temp Low - Circuit High - G42

The cars performance does not seem to be getting worse tho, although it does misfire during the start of some journeys.

If you have a shareware version of VAG-COM you can't have performed the throttle body re-alignment after cleaning it. The other codes could be down to an air leak and the crankcase ventilation system is a common culprit. You need to do the TB alignment before you go any further and take a look at the small diameter breather hose that comes out of the crankcase ventilation unit on the front of the block. Also check the rest of that ventilation system but it is very difficult to get at.

yeah i have to take it to a mate of mine at VW to get it done but i havnt had a chance to get there yet. one thing that has been common recently is that it seems to misfire approximately 2-3 minutes after setting off wheras it previously happened imidiately after ignition 2-3 seconds! this seems to be the case having cleaned the TB. not sure if this sheds any light at all. i do plan to check the connections of all the breathers. The car has not been as bad since i have replaced the 2 damaged ones about a month ago. There could still be another but like you say there not easy to examine, specially when the only time you can look at it is after work when its almost pitch black!
is there any test that you can do on the breather system without having to take each individual prpe off or check its connection (i.e. pressure tests?)

There is a pressure test method but you need some pretty serious kit to do it, removing and inspecting is the best way. On my VRS I found the hose from the crankcase breather "T" piece valve to the inlet manifold was split under a rubber jacket and the only reason I found it was that the engine was spotlessly clean after I replaced it then and later I noticed oil creeping out of the side of the jacket.

Quote:

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Originally Posted by suni4real

Im having difficulties with my car too..it seems to misfire, the revs move up and down, however they do become stable sometimes, it is so annoying though..what could the probem be???

i've been reading up on various articles, theres so many suggestions, the most popular one(s) being:
~ coil pack
~ spark plugs
~ egr valve
~....etc

How would you know which one is to be replaced??
It costs an arm and a leg to get all of them changed, especially when labour cost more than the parts sometimes, theres no point tryin trial and error unless uv got money pourin outta yo backside..

I hope someone can help..would really appreciate it.

Cheerz (",)

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alot of people forget to check breather hoses if they split they will suck in too much air this produces a weak mixture inturn this will create a miss fire...

Quote:

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alot of people forget to check breather hoses if they split they will suck in too much air

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Not only suck but on a turbo engine the allow boost to escape which causes poor acceleration delivery which is what we were talking about above. The pipe in question leaks under vacuum and boost and is a common problem on the 1.8T as they age.

Hiya guys,
I took my car to the garage, they put it onto a diagnostics machine and guess whats..nothing...i dint know wether i should be jumping for joy or to or pull my hair out..lol

I've got another problem though now..i used money more than brain today, i bought a Turbosmart dump valve today within 20 minutes of head turning around town two lights have switched on..from my understanding. ONE is the TRACTION CONTROL LIGHT & the other is the ENGINE MANAGEMENT LIGHT, should this have happened i paid 160 quid for this peice of gear..
Now these stupid yellow symbols on the DASH have become so annoying; it makes me not want to drive..
How can i put this right?? If i replce with my standard BOSCH one would the problem go away?? or are the lights going to stay on until Ivisit VW dealers???Sorry im clueless.
The garages around here just want to descimate you out of your pockets and i really dont want to be a victim..
perhaps one of you wise and smart guys can help???

Plz Help??!!
Would definetly be appreciated..

External venting or non original valves can cause engine running problems, I will only use the APR R1 which so far have not caused me or my customers any issues and they are quieter than the original so you don’t look like a knob when driving the car. I have removed more aftermarket valves than I have the unreliable original VAG items, get another fault code read done to see what has happened.

I won’t even fit this rubbish, new mind sell it. They should come with a Burberry cap, white shell suit an imitation thick gold chain included in the deal, and they would be worth more than the stupid valve as well.

still struggling crasher!!! im trying to get my mate at vw to have a look at my engine to see if he can shed any light on the problem that i am experiencing but hes always busy. i now have access to a registered version of vagcom and have removed all DTCs and readapted the TB. the main fault that i am getting now is that the G28 sensor is showing an intermittant fault. where is this sensor located? (its a 1.8t AUM 2002) i assume that it is on the block somewhere as it is measuring the engine speed. if this has a poor connection could this cause the car to refuse to start after it has stalled at startup? when the car begins to fire after playing up some mornings, it misssfires badly. if you keep trying to turn the engine it begins to start after plenty of turning of the engine and then returns to normal after 30 seconds or so of warming up.
basically i just want to check the connections of this sensor as a last resort before admitting defeat and handing it over and spending mass amounts of money but i am struggling to find any info on the net as to where it is located.
cheers

The sensor is at the front of the engine down near the sump and bolted through the block right up against the gearbox end so that it points at the 60-2 disc which is bolted to the rear web of the crankshaft. It is quite rare for these to play up.

Hi, Im having misfire problems too. Its a 2002 golf 2.0 gti, engine AQY. The car performs fine but when sitting still the rev needle moves up and down ever so slightly. The engine management light is constantly on now now. Any ideas?