I just installed a new o2 sensor after not passing emmisions, a comon first concideration. My question is when i brought the car into the a shop they told me my ignition timing and fuel injector timeing were advanced all of the way as if there were a chip. Well other that aftermarcket , all emmisions legal, exhaust the car is stock and i just bought it last year when it was totally stock i thought. So can a messed up o2 sensor cause the computer to try to compensate with a fully advanced timing command for ignition and injectors?

Thanks for all of the help, just a nother teenager trying to learn as much as he can about his car.

Thanks again,
Eli Jacobson
Raptere

 

A new O2 sensor can make a dramatic difference if the old one was just that, old, slow and not so good, which is always possible.

I do recommend that you check if there is an aftermarket chip in the ECM. Even though most will not affect emissions you never know. Passenger side, drop the hush panel and the ECM is up above. Can reach up push the bottom forward and it will drop out (silver box if original).

There should be a service number on it of 1227730. A small cover with two screws, remove screws. Under that should be the MEMCAL with a blue cover over it. Let us know what you find.

A '91 TPI should pass emissions easily. If you have the numbers & the gases they tested for a post/seach on the general tech board would be helpful.

RBob.

 

thanks ill have to chekck that