citrushills

I parked my 93 in the garage and about a week later, went to start it and would crank but wouldn't start. I checked the fuel pump power and that was good, so i checked for spark and nothing. I ordered a ICM online and installed it today. Now it will start but will only run for about 1 second. If I go to restart it, same thing. Could the new ICM be bad? Would it behave that way? If I put the old ICM on it has no spark at all so I know that one was bad. Any suggestions?

Cliff Harris

Check the connectors related to the ICM. It is very common to get corroded pins. The ECM needs the spark signal from the ICM to synchronize the firing of the injectors to the rotation of the engine.

Check for error codes:

http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm

What they mean:

http://forums.corvetteforum.com/1576116036-post35.html

citrushills

Replaced the ICM Harness Connector. Appears this was the problem. I put the original ICM in to test and that works as well. So now I have two. The dealer said it is very common for the connector to go bad.. The replacement one looks different than the original. Dealer said shouldn't be any problems with the new style one. Thanks for the help.

Cliff Harris

I have heard this many times. It appears to be a problem with the connector pins corroding and not making a good connection. I would think that dielectric grease would help in this case.

citrushills

From what understood from the mechanic, the pins on the ICM are manufactured very small in diameter. The connector is mechanical and from the heat, not so much corrosion, gets enlarged and will no longer make tight contact with the undersized pins on the ICM.