New Ignition control module
Thread Starter
5th Gear
Joined: Jun 2021
Posts: 5
Likes: 0
New Ignition control module
I have code 42 on my 1987 corvette and after going through troubleshooting procedures I decided to replace ignition control module with GM one and after I replaced it car won't start.I tried to use aftermarket ICM and car still won't start but if I put in old one car starts with no problems. I'm really confused. Is there anyone with same problem and do I need to reprogram new one after installation?
Last edited by Sahbaz; Jun 12, 2021 at 03:56 PM.
Melting Slicks
Joined: Jun 2011
Posts: 2,371
Likes: 383
From: Leland , North Carolina
It's a problem now with these cars . I had a similar situation. No start with a new one and a failure with another one after a short time. They are mostly Chinese junk.
Which aftermarket did you buy?
Which aftermarket did you buy?
Racer
Joined: Feb 2020
Posts: 482
Likes: 109
From: Fairfax, Virginia
I went through 4 from O'Reilly before I got one that worked, ended up building my own tester to verify they worked before putting them in the car. Atleast it had a lifetime warranty and all I had to do was call ahead
Last edited by ThatOneKid; Jun 13, 2021 at 08:43 AM.
Racer
Joined: Feb 2020
Posts: 482
Likes: 109
From: Fairfax, Virginia
If you have a multimeter measure the pickup coils output (2 wire connector on right side) while cranking, it should measure between 0.8 and 3V AC not DC, anything below that will not trigger the ICM. In my case it was a faulty pickup coil that acted like a faulty ICM.
Does your tach read around 200-300 RPM while cranking is another easy test but not everyone's tach works well.
Does your tach read around 200-300 RPM while cranking is another easy test but not everyone's tach works well.
Last edited by ThatOneKid; Jun 13, 2021 at 11:05 AM.
Melting Slicks
Joined: Jun 2011
Posts: 2,371
Likes: 383
From: Leland , North Carolina
[QUOTE=ThatOneKid;1603587296. In my case it was a faulty pickup coil that acted like a faulty ICM.
[/QUOTE]When He put's the old one back in it starts which probably rules that out.My pick up coil was wasted due to oil creeping up into my distributor.
[/QUOTE]When He put's the old one back in it starts which probably rules that out.My pick up coil was wasted due to oil creeping up into my distributor.
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Racer
Joined: Feb 2020
Posts: 482
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From: Fairfax, Virginia
Last edited by ThatOneKid; Jun 13, 2021 at 03:32 PM.
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