engine problem
Discussion
Help!
Model S3 V6
Under load the engine seems to hunt / misfire.
This problem started when the the fuel mixture was adjusted to reduce the exhaust emissions for the MOT.
The car was then serviced (at a TVR dealership!!). They have replaced the throttle pot., HT leads and distributor cap.
Any ideas?
Model S3 V6
Under load the engine seems to hunt / misfire.
This problem started when the the fuel mixture was adjusted to reduce the exhaust emissions for the MOT.
The car was then serviced (at a TVR dealership!!). They have replaced the throttle pot., HT leads and distributor cap.
Any ideas?
Hmm.
Did they replace the bits to try to cure the hunting?
Get it set up for timing (depending on whether you use boggo unleaded or Optimax / Super), then get it run on a rolling road to adjust the fuelling throughout the rev range on load.
I would suggest that it is either simply the fact that the fuelling is incorrect now - or that the garage who did the MOT knackered the AFM(s) by excessive adjustment.
Good luck, mail me if you need further info.
Marcus
Did they replace the bits to try to cure the hunting?
Get it set up for timing (depending on whether you use boggo unleaded or Optimax / Super), then get it run on a rolling road to adjust the fuelling throughout the rev range on load.
I would suggest that it is either simply the fact that the fuelling is incorrect now - or that the garage who did the MOT knackered the AFM(s) by excessive adjustment.
Good luck, mail me if you need further info.
Marcus
Thanks for your suggestion Marcus.
I took the car to www.autopoint-tuning.co.uk they have a rolling road. Within minutes I was asked "who had been tampering with the air flow meters" - factory set units! The black plastic covers had been removed and the mechanism inside each unit had been reset. The timing was also incorrect (the distributer was about 5 degrees out).
This "tampering" was carried out to get around the high emmission problem when the engine is on low rpm. and get the car through the MOT test. - the result too weak a mixture when the engine is under load.
It really is beyond comprehension why a TVR dealer should do this, and then go on to replace parts unrelated to a problem they caused. -- I'm being too polite here! I'm ****** angry.
Autopoint recalibrated the air control meters adjusted the timing. The RR test gave 168bhp. The problem of high emmisions at low rpm persisted but at least I can out-perform M.Minors!
Today Autopoint had the car back to try and isolate the problem. Checked - injectors, fuel pressure, EMU, rechecked the ACMs - the calibration had drifted and was reset - emmissions still high.
Any ideas? - other than to replace the ACMs - How much do they cost?
Andrew
I took the car to www.autopoint-tuning.co.uk they have a rolling road. Within minutes I was asked "who had been tampering with the air flow meters" - factory set units! The black plastic covers had been removed and the mechanism inside each unit had been reset. The timing was also incorrect (the distributer was about 5 degrees out).
This "tampering" was carried out to get around the high emmission problem when the engine is on low rpm. and get the car through the MOT test. - the result too weak a mixture when the engine is under load.
It really is beyond comprehension why a TVR dealer should do this, and then go on to replace parts unrelated to a problem they caused. -- I'm being too polite here! I'm ****** angry.
Autopoint recalibrated the air control meters adjusted the timing. The RR test gave 168bhp. The problem of high emmisions at low rpm persisted but at least I can out-perform M.Minors!
Today Autopoint had the car back to try and isolate the problem. Checked - injectors, fuel pressure, EMU, rechecked the ACMs - the calibration had drifted and was reset - emmissions still high.
Any ideas? - other than to replace the ACMs - How much do they cost?
Andrew
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