Questions and Answers

Z-28 Running Rich

Q. I have a 1982 Z-28 with 134,000 miles on it. I ran the old 5.0 hot and cracked the block. I bought an early 80's 350 cid engine and put it in the car. The car has the cross-fire injection system. The car runs fair, but is very sluggish on take off. Also it runs very rich. I'm at wit's end to figure out what to do. Do you have any suggestions?

Donn

A. I'm assuming you used the basic engine and took all the specific parts from the old one and put them on the replacement. Since most of the components look similar from one year to the next, the specifications may be quite different.

If it's running rich, then you need to look at the O2 sensor and make sure it's operating correctly. Also the coolant temp sensor may be the incorrect one or bad. Injectors may be a problem as well. If they are opening too long, you may have a problem with the ECM. They may be dirty and not closing completely allowing fuel to dribble past into the engine.

Another possibility is a bad fuel pressure regulator or fuel pump. You will need to check the fuel pressure to make sure it is within specs and determine if there is a problem.

There are any number of other things that can cause a rich running condition. The best this to do would be to scope the engine and find out exactly where the problem is.