Black Smoke and Runs Rich

DAMON

MEMBER
GMC SAFARI

I have a 1992 GMC Safari SLE 4.3L CMFI Motor 2WD 201005 Miles that is blowing out black smoke, has a very rich gas smell and has went from 22 MPG to 6MPG. I did a code check and got one error Code 45 rich exhaust, I cleared the code and drove about a block and rechecked
and recieved no code. This is what I have done to try to fix it, I have replaced the oxygen sensor, coil, distributor picup, rotor and cap, engine temp switch, oil sending unit, and I did a fuel pressure test that was within range.

Anyone have any ideals?

2 Replies

BURRBRIAN

MECHANIC
158 POSTS

I think if I went that far plugs would probably be in order along with a compression check. Sounds like you could have oil rings wore out. These electronic and computerized things aren't really my strong areas but seems like like you are passing a lot of unburnt fuel and burning some oil. Are you going through a lot of oil? Lost some of the git-up-and-go that it used to have?With that many miles on it you may be looking at things just being plumb wore out internally, meaning a rebuild is something you might consider in the near future. But on this my word is not gospel, just some more things to look at.