I have a 1990 Oldsmobile Cutlass Ciera with a 3.3L V-6 engine in it , that backfires through the throttle body while trying to start, if you crank it over and hold the accelerator pedal to the floor it'll eventually start, it'll idle rough but if you speed the engine up it'll smooth out. Also if you put it in drive, hold the brake and press the accelerator down it'll go " pop pop pop " The car has 218,000 miles on it and it has a clack clack clack noise coming from the passenger side of the engine. Could it possibly be the timing chain bad or has the timing jumped?
Backfiring on 1990 Oldsmobile Cutlass Ciera
2 answers 1 comment
The clacking sound could be the timing chain tensioner has failed,leaving excess chain slack and the popping sound in the intake could be a mechanical problem with an intake valve or the valve face is burned causing compression leakeage on that cylinder.And it could be a combination of electrical timing and mechanical failures.
It sounds like you may have some internal engine problems, maybe something with the intake valves or valve springs causing the backfiring back up thru the throttle body and possibly causing the clacking noise also. I suggest you get a reliable shop to check it out for you. Good Luck
turned out to be a bad #2 / #5 coil pack, replaced it and now the car runs fine