Audi S8 start up problem !!!
#31
Don't know about newer S*, but problem on older Audis:
Check failing Ignition Switch often caused by too many keys - works cold, poor or no start after even short drive;
Same for 'cold start' injector sys. leaking inc. Faulty Emission control system.
Check for Carbon buildup inside intake sys. that Audi is 'ignoring'!
Check failing Ignition Switch often caused by too many keys - works cold, poor or no start after even short drive;
Same for 'cold start' injector sys. leaking inc. Faulty Emission control system.
Check for Carbon buildup inside intake sys. that Audi is 'ignoring'!
#32
Hi there guys, i really have a problem with an Audi S7 4.0 TFSI.What could case sluggish engine running and stopping with no errors whatsoever?If it s cold, it runs for 2 minutes and afterwards starts to stutter and eventually stops.In order to run again i must press the acceleration pedal along with brake pedal and it stops again after starting.If i continue to accelerate it, it has serious backfiring.I left the car at two Audi dealers, what they managed to do was just to destroy my turbos.So I bought new turbos and after 100 kms the car started backfiring again and trashed these turbos also.I took the car back from the Audi dealership and changed the ECU.Still same behaviour, i got just misfiring on cylinder1.I changed all of you could think of, HP pumps,spark plugs,ignition coils, etc.I can make a small movie and upload it here if it can help.
#33
Audiworld Junior Member
Hi there guys, i really have a problem with an Audi S7 4.0 TFSI.What could case sluggish engine running and stopping with no errors whatsoever?If it s cold, it runs for 2 minutes and afterwards starts to stutter and eventually stops.In order to run again i must press the acceleration pedal along with brake pedal and it stops again after starting.If i continue to accelerate it, it has serious backfiring.I left the car at two Audi dealers, what they managed to do was just to destroy my turbos.So I bought new turbos and after 100 kms the car started backfiring again and trashed these turbos also.I took the car back from the Audi dealership and changed the ECU.Still same behaviour, i got just misfiring on cylinder1.I changed all of you could think of, HP pumps,spark plugs,ignition coils, etc.I can make a small movie and upload it here if it can help.
#34
AudiWorld Super User
Low tech: bad brake light switch as one long shot? Brake switch causes throttle to cut back.
From D3 (4.2 V8): Maybe the engine crankshaft position sensor? Crank sensor is essentially ground zero for all motor controls, telling ECU where the motor position is that everything else relies on. Known D3 failure point, and also known that is may not show any codes--sometimes does, sometimes doesn't. Also acts erratically on D3 often--not just an outright failure.
From D3 (4.2 V8): Maybe the engine crankshaft position sensor? Crank sensor is essentially ground zero for all motor controls, telling ECU where the motor position is that everything else relies on. Known D3 failure point, and also known that is may not show any codes--sometimes does, sometimes doesn't. Also acts erratically on D3 often--not just an outright failure.
#35
Low tech: bad brake light switch as one long shot? Brake switch causes throttle to cut back.
From D3 (4.2 V8): Maybe the engine crankshaft position sensor? Crank sensor is essentially ground zero for all motor controls, telling ECU where the motor position is that everything else relies on. Known D3 failure point, and also known that is may not show any codes--sometimes does, sometimes doesn't. Also acts erratically on D3 often--not just an outright failure.
From D3 (4.2 V8): Maybe the engine crankshaft position sensor? Crank sensor is essentially ground zero for all motor controls, telling ECU where the motor position is that everything else relies on. Known D3 failure point, and also known that is may not show any codes--sometimes does, sometimes doesn't. Also acts erratically on D3 often--not just an outright failure.
#36
Hi there guys, the car's problem is ****in bizarre.So, by checking all possible causes, my brother unfilled the oil cap and BAM!, car idling again!We had some fun with covering the hole for a few times.Actually the vacuum created there was so great when I was accelerating that my brother barely could lift his palm from the oil cap.We stopped the car and when we started it again, it continued to idle flawlessly even if we put back the oil cap.We are indeed baffled because since then the car runs as it should and I couldn t reproduce the issue that the car had for over a year.I leave the videos to see for yourselves.Anybody, any idea? I m guessing some kind of throttle body glitch,I don't know.It has to do it again to investigate further.
So,with oil cap off :
After 10 minutes with oil cap on, running smoothly :
So,with oil cap off :
#37
but it where is the HPFP’s located? Thanks
#38
Just wanted to post a relevant TSB for anyone having startup fuel issues.
https://static.nhtsa.gov/odi/tsbs/20...55649-9999.pdf
AUDI TSB # 01 19 00 2046724/7
which superseeds the technical bulletin theyve know about this problem for a while! Technical Service Bulletin Group 01 number 18-73. It looks like Audi has know about this since 2017
AUDI TSB # 01 19 00 2046724/7
which superseeds the technical bulletin theyve know about this problem for a while! Technical Service Bulletin Group 01 number 18-73. It looks like Audi has know about this since 2017
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DocTJ (11-01-2019)
#39
My Audi A8 2015 4.0 TFSI had an engine failure at 29.500 kms. Microfilter was blocked and prevented oil supply to turbos. Engine has now been rebuilt but a couple of ECS failure codes persist.
- Engine revs limited to 4000 rpm. Typically this happens soon after engine has been started. Often when car is turning sharply. The failure light sometimes goes off once you drive a bit longer.
- In the occasion rpm limit goes away, the engine start stop system shows failure code
- the third problem is related to misfiring
I suspect that these codes come from variable valve system solenoids, or sensors. The failure code indicates that the variable valve system reacts too slowly.
I understand that this is rather a typical prblem for Audi A8 with 4.0 TFSI engine. I have installed ABT tuning box to my car.
Any ideas and help would be greatly appreciated. I have already spent a lot on having the engine rebuilt.
- Engine revs limited to 4000 rpm. Typically this happens soon after engine has been started. Often when car is turning sharply. The failure light sometimes goes off once you drive a bit longer.
- In the occasion rpm limit goes away, the engine start stop system shows failure code
- the third problem is related to misfiring
I suspect that these codes come from variable valve system solenoids, or sensors. The failure code indicates that the variable valve system reacts too slowly.
I understand that this is rather a typical prblem for Audi A8 with 4.0 TFSI engine. I have installed ABT tuning box to my car.
Any ideas and help would be greatly appreciated. I have already spent a lot on having the engine rebuilt.
#40
AudiWorld Junior Member
HEllo ! I have an Audi S8 2014 4.0TFSI - 520 Hp , and for some time , my car have issue on start up ... bassicly it won t start until I press the acceleration pedal ... I have changed Both of the High Fuel Pressure Pomps , all 8 injectors , the oil separator ....and still my car won t start up from time to time .. for example in the morning the car strat perfect , and after i will run 20 km and stop , after 10 minutes when i want to start the engine again , it will won t start