: 1980 Eldorado 5.7 failed smog test, running rich



Eldorado guy
09-10-11, 04:25 PM
Hey everyone, so the Cadillac just failed it's first smog test while under my ownership. The tech said that it's running rich and for me to maybe look into the 02 sensor and the MAP sensor.

I replaced the computer with a reman unit a couple thousand miles back, and the map sensor is mounted on the ecm, so it should be ok. The 02 sensor isn't very old either, but if the car has had an existing issue for a while, I can't rule it out, as it may be shot again.

I know that it has issues with the throttle position sensor. I can't seem to get it tuned just right. The miss becomes less and less the more I fool with the sensor, but I just can't hit that window, so I'm assuming it's most likely worn out. I have a factory service manual and I've been adjusting it as it says, with a .020 feeler gage. It has a miss at low speeds and sometimes the car will stall, like if driving in a parking lot or driving in reverse. I adjusted it once again before I left, thought it would be better, but when he put it on the dyno, it missed like crazy at lower rpms. I don't know if a tps can cause a rich condition.

Anyone have any ideas? Suggestions (apart from move out of California lol)?

Thanks,
Dan