Exhaust smells rich

[wiresman]

Man does time fly, still have the ?83 Delorean. It sets often but I keep the fuel changed and run it when I get a chance. Ive noticed lately that the exhaust smells rich, even though my CO dwell reading is still between 30-50 when at operating temp. Its actually smelled that way for a few years or better but as long as it starts and I made it to some local car shows I didnt mind much. Now that Im not so busy, Im wondering if it could be a bad O2 sensor or if there are other things I should look at such as fuel pressure. It doesnt seem to purr like it did back in the early 90?s. Anyone have any advice?

[Rich]

Man does time fly, still have the ?83 Delorean. It sets often but I keep the fuel changed and run it when I get a chance. Ive noticed lately that the exhaust smells rich, even though my CO dwell reading is still between 30-50 when at operating temp. Its actually smelled that way for a few years or better but as long as it starts and I made it to some local car shows I didnt mind much. Now that Im not so busy, Im wondering if it could be a bad O2 sensor or if there are other things I should look at such as fuel pressure. It doesnt seem to purr like it did back in the early 90?s. Anyone have any advice?

Any of the many K-Jet engines from that era, including this one, are designed to run rich during warmup from a cold start. That's a consequence of the control pressure regulator temporarily enriching the mixture for good driveability. The cat can't reduce the HC in the exhaust until it reaches temperature, either. So, yes, you'll smell a rich exhaust for a 2-3 minutes after a cold start. You mention it's been doing that for a long time which fits with this story.

While it's warming up it may idle a bit higher, too. Also normal. Not sure if that's what you meant by it not purring like it used to?

[82DMC12]

Man does time fly, still have the ?83 Delorean. It sets often but I keep the fuel changed and run it when I get a chance. Ive noticed lately that the exhaust smells rich, even though my CO dwell reading is still between 30-50 when at operating temp. Its actually smelled that way for a few years or better but as long as it starts and I made it to some local car shows I didnt mind much. Now that Im not so busy, Im wondering if it could be a bad O2 sensor or if there are other things I should look at such as fuel pressure. It doesnt seem to purr like it did back in the early 90?s. Anyone have any advice?

Just to clarify, when you say the CO / dwell reading is 30-50, you are talking about the 4 cyl scale?

If you have the original catalytic converter, perhaps the cat is internally damaged, this would increase fuel odor and perhaps change the exhaust sound.