2.0 TDI 140 misfire when cold.
Discussion
Hi
I have quite a specific issue with my 2003 Audi A3 2.0 TDI 140...
When accelerating from a cold start (only with light throttle), particularly when going up hill, there is a very noticable stutter/hesitation/misfire from around 1600 RPM upwards. From experience it feels like fuel starvation - the hesitations only last half a second then there will be a surge of power, followed by another hesitation etc. This will generally happen for around 2 minutes (only under acceleration) until the engine is warmish and then the engine will run smoothly for hours. If the engine is stopped, even for say 5 or 6 hour, it will not suffer from the problem when restarted - only when the engine is fully cold, i.e left overnight. On a warm sunny day the problem will barely be noticeable, even on a cold start, where as on a cold morning, the misfire seems much more dramatic and lasts for longer. There is a fault stored with a couple of the glow plugs, however the car starts perfectly every time, even in cold weather so I don’t see that this can be the problem, unless they play another role that I am unaware of? I found many cases on online forums of people who have a similar misfire, but only when the engine is warm. Is it possible that a temperature sensor is broken and so the engine fails to realise its cold, therefore not injecting enough fuel when cold?
I have had this problem for around 6 months now, during which time it appears not to have gotten any worse, although the season might be helping it a bit. Incidentally I had a new turbo fitted only a few weeks before I first noticed the problem.
If anyone else has heard of this problem or has any suggestions as to what the cause might be, it would be much appreciated…
I have quite a specific issue with my 2003 Audi A3 2.0 TDI 140...
When accelerating from a cold start (only with light throttle), particularly when going up hill, there is a very noticable stutter/hesitation/misfire from around 1600 RPM upwards. From experience it feels like fuel starvation - the hesitations only last half a second then there will be a surge of power, followed by another hesitation etc. This will generally happen for around 2 minutes (only under acceleration) until the engine is warmish and then the engine will run smoothly for hours. If the engine is stopped, even for say 5 or 6 hour, it will not suffer from the problem when restarted - only when the engine is fully cold, i.e left overnight. On a warm sunny day the problem will barely be noticeable, even on a cold start, where as on a cold morning, the misfire seems much more dramatic and lasts for longer. There is a fault stored with a couple of the glow plugs, however the car starts perfectly every time, even in cold weather so I don’t see that this can be the problem, unless they play another role that I am unaware of? I found many cases on online forums of people who have a similar misfire, but only when the engine is warm. Is it possible that a temperature sensor is broken and so the engine fails to realise its cold, therefore not injecting enough fuel when cold?
I have had this problem for around 6 months now, during which time it appears not to have gotten any worse, although the season might be helping it a bit. Incidentally I had a new turbo fitted only a few weeks before I first noticed the problem.
If anyone else has heard of this problem or has any suggestions as to what the cause might be, it would be much appreciated…
Hi. I get a simular problem with my 2008 audi a4 but i get the missfire/jerk when the car has been driven a while ( warm engine)
Not so sure what your problem is, i will ask arround. But maybe you mite be able to help with mine. You wrote on your post u read about the same problem but when the engine is warm. Were can i find this?
Thank you
Not so sure what your problem is, i will ask arround. But maybe you mite be able to help with mine. You wrote on your post u read about the same problem but when the engine is warm. Were can i find this?
Thank you
I think this is the thread I was thinking of...
http://www.audi-sport.net/vb/a3-s3-sportback-8p-ch...
Could just be a dirty fuel filter? Weird though that yours only does it when warm, and mind when cold.
Lots of chat about dodge injectors too
Hope you find what your looking for.
http://www.audi-sport.net/vb/a3-s3-sportback-8p-ch...
Could just be a dirty fuel filter? Weird though that yours only does it when warm, and mind when cold.
Lots of chat about dodge injectors too
Hope you find what your looking for.
willthebrill said:
Mileage is 138k so fairly high. I ran reddex for 5 or 6 consecutive tanks. I thought there was a slight improvement at first, however it didn't seem to be significant. I've not heard of Millers before so I will give that a go.... thanks for the suggestion!
I've not experienced millers but heard good things about it. It's quite pricey and available on line. I've looked at halfords before but they didn't have it.Hi Matey
I had a 2007 A4 once with the same problem, I took it to Audi twice but they could fine nothing wrong (if it's not showing an error code there must be nothing wrong!!)
Looking around the internet, it is full of people with the same issue, and it just seems to be a trait of the engine I'm afraid, with no known resolution, I don't think it indicates a problem as such, and you won't ruin the car by driving it, but think it just has to be lived with for now.
Read more here, This is about the Passat, but again it's the same engine used:
http://www.vwaudiforum.co.uk/forum/showthread.php?...
I had a 2007 A4 once with the same problem, I took it to Audi twice but they could fine nothing wrong (if it's not showing an error code there must be nothing wrong!!)
Looking around the internet, it is full of people with the same issue, and it just seems to be a trait of the engine I'm afraid, with no known resolution, I don't think it indicates a problem as such, and you won't ruin the car by driving it, but think it just has to be lived with for now.
Read more here, This is about the Passat, but again it's the same engine used:
http://www.vwaudiforum.co.uk/forum/showthread.php?...
Technically, a 'misfire' on a diesel only happens if an injector plays up, or is blocked, but as it's fine when hot, I'd not waste much more time on those. The engine should have a crank and /or cam sensor to know when to fire the injectors and therefore will have misfire detection. i.e the O2 sensor will show a momentary richness for cylinder X on it's power stroke. Any such codes when the ECU was interrogated? Is it smoking more than usual from the exhaust pipe under acceleration?
willthebrill said:
Incidentally I had a new turbo fitted only a few weeks before I first noticed the problem.
That's where I'd focus your attention. If it's a variable vane turbo, they can 'stick', causing boosting problems, which will feel like hesitation. Perhaps the heat is making what ever is sticking free off?Thanks for the link gregpot - I hadn't seen that one. It sounds like it could be any number of things...
Supercharged, I do remember there being a misfire registered on one (possibly two) of the cylinders last time it was scanned. I think I was so wrapped up in the turbo issue at that stage that I assumed it was related to that. I haven't scanned the ECU recently but I'm getting a service soon so I guess there could be a load more errors.
I actually had a new turbo fitted around the time the 'misfire' started occurring (6 months ago) so I don't think the vanes should be sticking. The vanes on the old turbo were definitely sticking because it would over boost and go into limp mode - the new turbo resolved this. I have noticed more black smoke than normal when flooring it though.
I feel like it could be a sensor fault of some kind being responsible for the choke not putting in enough fuel when the engine is cold... would that be possible?
Supercharged, I do remember there being a misfire registered on one (possibly two) of the cylinders last time it was scanned. I think I was so wrapped up in the turbo issue at that stage that I assumed it was related to that. I haven't scanned the ECU recently but I'm getting a service soon so I guess there could be a load more errors.
I actually had a new turbo fitted around the time the 'misfire' started occurring (6 months ago) so I don't think the vanes should be sticking. The vanes on the old turbo were definitely sticking because it would over boost and go into limp mode - the new turbo resolved this. I have noticed more black smoke than normal when flooring it though.
I feel like it could be a sensor fault of some kind being responsible for the choke not putting in enough fuel when the engine is cold... would that be possible?
A faulty MAF causes inaccurate fuel metering, which would definitely lead to excessive smoke, flat spots and poor economy.
If you're using VCDS (previously called VAG-COM), you can monitor the MAF's grammes/sec output in the Measuring blocks. I don't know what the 'expected' g/s should be on your engine though because diesels have no throttle, so the readings will be completely different to the petrol more engines I'm used to working on.
The MAF would affect all 4 cylinders though, so if you've seen a misfire fault code on 1 or 2 cylinders, perhaps you do have an injector issue, or maybe the solenoids controlling them. Does this engine have a reputation for dodgy injectors?
If you're using VCDS (previously called VAG-COM), you can monitor the MAF's grammes/sec output in the Measuring blocks. I don't know what the 'expected' g/s should be on your engine though because diesels have no throttle, so the readings will be completely different to the petrol more engines I'm used to working on.
The MAF would affect all 4 cylinders though, so if you've seen a misfire fault code on 1 or 2 cylinders, perhaps you do have an injector issue, or maybe the solenoids controlling them. Does this engine have a reputation for dodgy injectors?
It did turn out to be injector related in the end.
It was misfiring on the same cylinder each time (I can't remember if it was 1 or 2) so the mechanic decided to swap the injectors on cylinders 1 and 2 around to see if the problem repeated on the same cylinder or moved to the other cylinder. The idea was that if the misfire reoccurred on the same cylinder then it couldn't be the injector itself that was at fault, where as if the fault moved with the injector then we would know to replace the injector.
The funny thing is that once the injectors had been swapped around the misfire completely disappeared and hasn't come back since. This was odd because no new/replacement parts had been fitted. We came to the conclusion that it might have been a faulty connection on the wiring loom and that in the process of moving ever thing around, the wires came to rest in a more favorable position which meant the cold misfire stopped.
As everything is now working fine (touch wood), I'm just hoping the problem will stay away. Anyway, although we don't actually know exactly what fixed the problem, it seems the wiring loom may have been the culprit.
Let me know how you get on trying to fix it...
It was misfiring on the same cylinder each time (I can't remember if it was 1 or 2) so the mechanic decided to swap the injectors on cylinders 1 and 2 around to see if the problem repeated on the same cylinder or moved to the other cylinder. The idea was that if the misfire reoccurred on the same cylinder then it couldn't be the injector itself that was at fault, where as if the fault moved with the injector then we would know to replace the injector.
The funny thing is that once the injectors had been swapped around the misfire completely disappeared and hasn't come back since. This was odd because no new/replacement parts had been fitted. We came to the conclusion that it might have been a faulty connection on the wiring loom and that in the process of moving ever thing around, the wires came to rest in a more favorable position which meant the cold misfire stopped.
As everything is now working fine (touch wood), I'm just hoping the problem will stay away. Anyway, although we don't actually know exactly what fixed the problem, it seems the wiring loom may have been the culprit.
Let me know how you get on trying to fix it...
Hi Will,
Many thanks for posting and especially with the fix for your car. Now many many years later I've been searching around and haven't found anyone else who has described the exact same problem as I have with my golf mk6 2.0 TDI. It too had a new turbo fitted but unsure where this has a role to play.
I'm searching now because winter's on its way and I know for sure that the hesitation will be back as it's been absolutely perfect throughout the summer.
So what you're saying is to maybe unplug the injectors and give the connectors a bit of a clean? I think I've actually removed these plugs before and looked to see if there was anything loose and also checked the voltage. Everything was fine. I also don't get any errors showing on the scan which doesn't help. Garages don't know what to say either ever.
Anyway I'm glad you found a solution to the exact same issues you've described because you're the only one! Did it happen again after the injectors were swapped around? I know you may not have the car now but I'd be interested to know if you got away without having to replace those expensive badboys.
Cheers,
Jon
Many thanks for posting and especially with the fix for your car. Now many many years later I've been searching around and haven't found anyone else who has described the exact same problem as I have with my golf mk6 2.0 TDI. It too had a new turbo fitted but unsure where this has a role to play.
I'm searching now because winter's on its way and I know for sure that the hesitation will be back as it's been absolutely perfect throughout the summer.
So what you're saying is to maybe unplug the injectors and give the connectors a bit of a clean? I think I've actually removed these plugs before and looked to see if there was anything loose and also checked the voltage. Everything was fine. I also don't get any errors showing on the scan which doesn't help. Garages don't know what to say either ever.
Anyway I'm glad you found a solution to the exact same issues you've described because you're the only one! Did it happen again after the injectors were swapped around? I know you may not have the car now but I'd be interested to know if you got away without having to replace those expensive badboys.
Cheers,
Jon
Hi Jon. Sorry to hear you are having the same problem. I don't have the car any more, but I don't think the misfire ever returned once it was "fixed". As far as I'm aware the garage just switched the injectors around and it started working. I suppose they may have cleaned them before switching cylinders so it could be worth you giving that a go. The only other thought was that it was just a freak fault in the loom that was fixed by moving it slightly.
I hope you manage to fix it without too much expense. Incidentally I also have a 2.0tdi mk6 now. 250k miles and never wanted anything more than brakes/tyres and regular servicing (touch wood!). Goes to show there is an element of luck with cars.
I hope you manage to fix it without too much expense. Incidentally I also have a 2.0tdi mk6 now. 250k miles and never wanted anything more than brakes/tyres and regular servicing (touch wood!). Goes to show there is an element of luck with cars.
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