check engine light

pizzo · #1 04-04-2005, 06:26 PM

got a vt II ss with a gen 3 and got a set of extractors and a twin 2.5" exhaust ever since the extractors been on the car the check engine light comes on after driving for a bit, taken it to holden dealer and they have replaced the o2 sensors 3 times and now they tell me that its just because its got extractors and the pcm is too finely tuned and picks the quicker exhaust flow up as a fault.

Has anyone had this problem or herd of this?

Demons1964 · #2 05-04-2005, 08:46 AM

I've heard of this as a common fault with fitting extractors (not specific to Gen 3) related to the positioning of the O2 sensor. Apparently when the O2 sensor is operating (i.e. when above 360 degrees C from memory which happens when you're at full operating temp) and it's positioning is slightly different than what is allowed for by the pcm it is picking up the engine running way too lean, computer compensates for it, then running way too rich, compensating for it, then running lean etc and your check engine light will come on. What Holden told you was right (except for the quicker exhaust flow). If I was you I'd get a professional exhaust centre who have dealt with this type of problem before to have a look at it.

Good luck,
Mark