running rich

[nates240sx]

I have an 89 240sx 5-speed. everything under the hood is stock and has been well maintained. Oil changed regular as well as plugs, wires, etc. It starts and runs fine, just runs rich and uses a lot of gas. It blows plumes of black smoke if you get on it but only after you hit 2nd gear and get on it again and through the rest of the gears. the whole rear bumper is black. any suggestions?

[nates240sx]

To add to that since i did a little search, could a bad alternator be the cause. When you first crank it up, you have to let it run for a minute and then slowly rev it up to 3 grand before it will start charging. All of the lights will get brighter. If you dont it will go dead. After that its fine.

[180fan]

a bad alternator? I guess if your voltage is sagging but not really likely. Did you ever change the o2 sensor, clean the element/connectors on the mafs, and also check over your tps settings?

[NateDogg]

I dont think a bad alternator could cause an engine to run rich, although you may still have a bad alternator.

First three things I would check are: air flow meter, o2 sensor, coolant temp sensor.

[freakyjason]

yeah^check the timing too. sometimes if its advanced it will run rich. also be sure to check stuff like o2 sensor, iacv, coolant temp, mafs, tps ect

[A31BLUEMONSTER]

sounds like what happens when a pipe coupling busts loose