1993 c4
Thread Starter
1st Gear
Joined: Jul 2018
Posts: 1
Likes: 0
From: Utah
1993 c4
Hello,
i just got this c4 and am having an issue with it. Sometimes the motor will just cut out while driving and won’t start again. Other times its when I stop somewhere and shut it off, then go to start it and nothing just cranks over. The icm has been replaced and has a gap from the block with washers from the previous owner. When I turn the key the last time I didn’t hear the fuel pump so I just replaced that. Went for a drive, stopped and then it wouldn’t start again. If I wait a while and cycle the key a few times i can get it to start again. Haven’t had it cut out while driving since I did the fuel pump but still does it after shutting it off but not all the time, any ideas?
i just got this c4 and am having an issue with it. Sometimes the motor will just cut out while driving and won’t start again. Other times its when I stop somewhere and shut it off, then go to start it and nothing just cranks over. The icm has been replaced and has a gap from the block with washers from the previous owner. When I turn the key the last time I didn’t hear the fuel pump so I just replaced that. Went for a drive, stopped and then it wouldn’t start again. If I wait a while and cycle the key a few times i can get it to start again. Haven’t had it cut out while driving since I did the fuel pump but still does it after shutting it off but not all the time, any ideas?
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
I had the exact problem you're having and it was an optispark problem. Replaced it and all was good. I can't remember exactly if it was the hi res or low res pulse, but one of the failures will cut the fuel system if i recall correctly.
Last edited by twichy2011; Jul 19, 2018 at 09:02 AM.
Pro
Joined: Dec 2004
Posts: 597
Likes: 24
Mine was doing that with some other odd things such as not starting sometimes when cold or hot and sometimes starting when cold or hot. Checked a ton of stuff. It was the ECM. Had it rebuilt for 166 dollars and no problems since December. If it only does it after the engines warmed up try icing the ECM right after you turn car off with an ice pack. If it starts after cooling down then it could be that. The solder joints get old and shrink after time and can separate when hot. Before I had the ECM rebuilt I checked fuel pressure and had a mechanic check injectors and most other suggestions here.
