Misfiring/engine management light now on!

[Tom-E]

Hi all. I've been trawling the forums and haven't really found the answer I'm after so thought I'd ask and put it out there. My car is a 2001 AMK S3 with 98k on the clock, and yesterday it developed a bit of a misfire/judder, it idles perfectly, but judders only on full throttle around 4000rpm. However, if you don't give it too much throttle and let it cruise past 4000rpm, it doesn't seem to be as bad (although not 100% performance). From what I've read, my first port of call was the coil packs, so I went out and disconnected them one by one, expecting one of them not to affect the idle if it was faulty. However, all 4 of them made the idle rough & lumpy, so not sure if it could still be one or not? So I took it for a spin round the block to see if it was still happening, then my engine light came on. Now I'm worried. It's coming up for service time so I guess plugs etc have been there a while, but I think this could be a bit more serious.
if anyone can help, or give any sort of advice it would be a help.
Tom

 

[Dani_B19]

Get it scanned mate to see what codes if any are coming up then take it from their. Could be faulty maf, dirty throttle body, coil pack wiring cracking, vac/boost leak etc.

 

[Alex C]

you already knew it wasn't misfiring at idle if it was idling perfectly. Pulling coil packs at idle just confirmed that

sounds like it could be misfiring when the engine is under high load - get it scanned and that will tell you what fault codes have been triggered

what about full throttle at 4,000rpm downhill?

Also, do you know about the Audi coilpack recall?

http://www.audi-sport.net/vb/a3-s3-forum-8l-chassis/125403-audi-coil-pack-recall.html

 

[Tom-E]

you already knew it wasn't misfiring at idle if it was idling perfectly. Pulling coil packs at idle just confirmed that

sounds like it could be misfiring when the engine is under high load - get it scanned and that will tell you what fault codes have been triggered

what about full throttle at 4,000rpm downhill?

Also, do you know about the Audi coilpack recall?

Thats a good point, guess I hadn't thought of that. Haven't tried full throttle downhill, but as I said letting it climb slowly to 4000rpm & above seems to be ok(not 100%, but not as bad as full throttle).

I'll get it scanned and see what it comes up with. So does it sound to you like it could be coil packs if its misfiring under high load? Just want to know if I'm thinking along the right lines, or if it could be more serious now the engine management light is on. I changed the MAF when I bought it, as I did that on my old golf turbo and it made a hell of a difference. Maybe I'll have the throttle body off too and get that cleaned & realigned.

Yea I had done a bit of reading and emailed Audi to get the ball rolling, but might be best to ring them tomorrow, and see how willing they are to do it!

Tom.

 

[Alex C]

yeah that is my best guess but a scan will be more definite I think the air/fuel mix needs a higher energy spark when the engine is under high load which means yo are asking more of you coilpacks which is when any weak links will reveal themselves. Is the misfire more noticeable at full throttle in higher gears than lower gears?

If you don't have VCDS/vagcom to scan the car then you may be able to find someone close by willing to help you out with that: http://www.audi-sport.net/vb/vcds-formerly-vag-com-forum/84603-***vcds-users-map***.html

Its better than paying audi for the privilage

either way ring your local audi dealer to talk about possibly getting your coilpacks replaced FOC if they are the push down variety. If you get them replaced you may find your misfire is solved

 

[Tom-E]

yeah that is my best guess but a scan will be more definite I think the air/fuel mix needs a higher energy spark when the engine is under high load which means yo are asking more of you coilpacks which is when any weak links will reveal themselves. Is the misfire more noticeable at full throttle in higher gears than lower gears?

If you don't have VCDS/vagcom to scan the car then you may be able to find someone close by willing to help you out with that: http://www.audi-sport.net/vb/vcds-formerly-vag-com-forum/84603-***vcds-users-map***.html

Its better than paying audi for the privilage

either way ring your local audi dealer to talk about possibly getting your coilpacks replaced FOC if they are the push down variety. If you get them replaced you may find your misfire is solved

Great, thanks for your input. There is a VW/Audi specialist garage up the road but will look at that users map too. Yes, the misfire is definitely more noticeable in higher gears, but it does also happen at full throttle in second as well (3rd seems to be the most noticeable)

Yea they are the push down variety, so fingers crossed. Looking around £80 for the set, so a FOC replacement would be nice!

Thanks again for your help. Put my mind at rest a bit, I was fearing the worst when the engine management light came on!

 

[Tom-E]

Just to let you know, phoned my local Audi dealer in Colchester on Monday regarding this recall, did a few checks and said it was outstanding on my car. Booked the car in for 8am this morning, all 4 coil packs were changed, full vehicle health check carried out, Valeted inside & out, & all the coffee I could drink! Well impressed with that. They also deleted the engine management code, and the airbag light that came on (repaired after the mrs in & out the back with kids). Took the car up the road, once warm I took it up to 4000rpm and hey presto, no misfire & all is well with the world. Unfortunately the next time I started it up the engine management light came back on, so I'm hoping its just a sensor or something, as it seems to be running beautifully. Due a service though, so taking it to local Audi specialist for all fluids to be changed, since its recently had new filters all round, brake pads, also got a set of ngk plugs to throw in at some point - can anyone tell me if the push fit coil packs just simply pull out to access the spark plugs? Don't wanna risk breaking them! Cheers.

 

[badger5]

pull out yes.. but they are tight..

 

[Tom-E]

Ok, I'll go easy. Did it on my golf turbo but they were bolt down's, sure it can't be too hard!

Don't suppose anyone here has had similar experience with changing coil packs and engine management lights coming on?

Tom

 

[turnstyle]

Alright mate.
Check your coil pack loom - could be goosed

I have had similar. Changed the faulty coilpack and the problem seemed to go. Couple of days later the same fault came back.
Had some spare time last weekend and started to strip the tape off the coil pack loom - loads of splits and bare wire showing.

Ordered a new loom from audi for £27 and im currently changing it this weekend. Started it about half 3 today and the splits go as far back as where the loom branches off to the injectors.
went dark so will finish tomorrow and see if the splits go further back.
Im in Colchester too so if you fancy seeing what to look for PM me and you can pop round and have a look if you want but to be honest its fairly obvious - the wire will have cracks and showing the copper wire underneath.

Im only planning on soldering in the new loom rather than going all the way back. The new loom isnt a straight swap in the S3 but its easy enough to match up wires.... Just a royal PITA to strip all the tape/plastic etc to expose the wires.