89 Dodge Aries K-Black Smoke from Muffler after car idles

[jxplorer]

I have a 1989 Dodge Aries K 4 cylinder 2.5 liter engine with an automatic transmission. When I start the car from a cold position, it idles smoothly. But after approximately 8-10 minutes, the car begins to idle rough and then black smoke comes out from the muffler instead of the normal gray smoke.

Hoping to address the root cause of the problem, I have installed the following parts: a new throttle body, a new EGR valve, a new distributor shaft and cap, a MAP sensor, a new coolant sensor, new spark plug wires, four new spark plugs, a new ignition coil and a new air cleaner filter.

Fellow forum users, do you have any ideas what could be wrong with the car?

[Pete in NH]

Hi,

Welcome to the club.

I suspect the issue has to do something with the control computer not knowing when the engine is warmed up and still maintaining the cold engine rich mixture. Could be any thing from a defective computer to a bad sensor or open connection.

A factory service manual would be a big help in making some tests and following wiring.