My car has been running rich for several years now, and I have not been able to find out what the cause is. I replaced the intake manifold gasket a few years ago and also checked for intake leaks and have also made sure that my vacuum lines are in good shape. Fuel injector o-rings were replaced several years ago and there were no other obvious issues.

Background information:

When I leave for work in the morning, after I back out of the driveway, when I step on the accelerator to go forward, my car releases a significant, but not obnoxious cloud of black smoke. It does not smoke at any other time.

I have wanted to replace the cold start injector for some time now however I hate to replace expensive parts ($235) on a hunch.

I found a low mileage 1990 240 DL with only 78,500 miles on it, and the cold start injector was still in place. I pulled the part, and I was only charged $1 for it at the junk yard.

I got around to replacing it this past weekend, and for the last three mornings, my car has not released the usual black cloud. I am going to pull the o2 sensor this weekend and clean off the black soot and then check it again in a month or so. I am also going to check my gas mileage, as I usually do when I fill up.

I hope that someone out there finds this information helpful.

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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 321,450 miles, will she make it to 400K ?? >>You haven't really worked on a car until you draw blood<< :-}