93 icm
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Joined: Jul 2023
Posts: 77
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93 icm
What is the catch with these Ignition Control Modules on amazon for $13.95 for a 93 corvette? They are $100 to $150 everywhere else. Anybody ever tried one? Are they any good? Don't know if that is whats wrong with my car but its worth a try. My car starts missing after driving on open road for about 10 or 15 minutes. Especially if I kick it down. It misses while idling too when it starts this. After it sits for a while it starts and runs good again for about 10 or 15 minutes.
5th Gear
Joined: Feb 2023
Posts: 5
Likes: 12
From: Mississippi
I am interested in what replies you get. My 94 M6 is doing the exact same thing. I replaced wires, plugs, coil and o2 sensors so far. Problem is still there. No Service Engine light and no codes. ICM is alot easier to change than the Optispark.
Instructor
Joined: Apr 2022
Posts: 142
Likes: 51
From: Central NY State
I have a 93, and did not go cheap on the ICM. A year ago it cost me $116. It was one of many ignition and computer issues I had at the time. Hasn't failed me after 3000+ miles.
GM Genuine Parts D1971A Ignition Control Module without Coil
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Joined: Jul 2023
Posts: 77
Likes: 5
My local shop suspected the distributor but I haven't had an opportunity to have it looked at. I did change the MAP sensor since it was so easy. Car seemed to run a little bit better but that didn't cure the problem. I think me and a buddy that's pretty mechanically inclined might try the ICM. If that doesn't do it, I'll take it to the shop. I'm gonna try easy and cheap first. I don't have any check engine lights or anything either. My car has less than 17,000 miles on it so obviously the battery goes dead pretty often. I'm not sure if it everything has to reset after the battery is charged or not.
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
I went with the GM branded ICM, and yea it wasn’t cheap off Amazon.
I would suggest instead of buying a cheap one “just to try” that you remove your existing ICM clean it and the heat sink really well and reinstall with fresh and high quality thermal paste (arctic silver). The thermal paste dries and leaks out over time and then you start having heat related issues. If this fixes it great!!! If it takes longer to have problems but you still have issues, then replace it.
FWIW - my ICM symptoms were like an off switch…not missing or running rough… your coil could be suspect too and generating weak spark when hot…always good to check fuel pressure too but unlikely.
After that opti would be suspect…what about CTS? What does the digital readout read when it starts acting up and is the coolant reading (digital) rational?
I would suggest instead of buying a cheap one “just to try” that you remove your existing ICM clean it and the heat sink really well and reinstall with fresh and high quality thermal paste (arctic silver). The thermal paste dries and leaks out over time and then you start having heat related issues. If this fixes it great!!! If it takes longer to have problems but you still have issues, then replace it.
FWIW - my ICM symptoms were like an off switch…not missing or running rough… your coil could be suspect too and generating weak spark when hot…always good to check fuel pressure too but unlikely.
After that opti would be suspect…what about CTS? What does the digital readout read when it starts acting up and is the coolant reading (digital) rational?
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Joined: Jul 2023
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I have decided to change the ICM on my 93. I will likely try to get a GM (or equivalent) replacement. I need to know exactly which paste I should use and where to get it? Also, I've not looked yet but does anything else need to be removed before taking off the ICM?
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Burning Brakes
Joined: Jun 2021
Posts: 1,199
Likes: 449
From: NJ
I’m having a similar issue with my car now. Except it only misses at idle when hot. Anything off idle and the car is super strong. I plan on replacing the ICM with a quality unit when I do the rest of the ignition related items in a tune up. I’m hoping after all that, it fixes the issue.
Burning Brakes
Joined: Jun 2021
Posts: 1,199
Likes: 449
From: NJ
I went with the GM branded ICM, and yea it wasn’t cheap off Amazon.
I would suggest instead of buying a cheap one “just to try” that you remove your existing ICM clean it and the heat sink really well and reinstall with fresh and high quality thermal paste (arctic silver). The thermal paste dries and leaks out over time and then you start having heat related issues. If this fixes it great!!! If it takes longer to have problems but you still have issues, then replace it.
FWIW - my ICM symptoms were like an off switch…not missing or running rough… your coil could be suspect too and generating weak spark when hot…always good to check fuel pressure too but unlikely.
After that opti would be suspect…what about CTS? What does the digital readout read when it starts acting up and is the coolant reading (digital) rational?
I would suggest instead of buying a cheap one “just to try” that you remove your existing ICM clean it and the heat sink really well and reinstall with fresh and high quality thermal paste (arctic silver). The thermal paste dries and leaks out over time and then you start having heat related issues. If this fixes it great!!! If it takes longer to have problems but you still have issues, then replace it.
FWIW - my ICM symptoms were like an off switch…not missing or running rough… your coil could be suspect too and generating weak spark when hot…always good to check fuel pressure too but unlikely.
After that opti would be suspect…what about CTS? What does the digital readout read when it starts acting up and is the coolant reading (digital) rational?
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
You mean the small bolts that hold just the ICM on? 8mm or something around there…I don’t remember and it will be easy to find out…
Do you have a FSM? The answers would be there if you want to know beforehand..,
Do you have a FSM? The answers would be there if you want to know beforehand..,
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Joined: Jul 2023
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For anybody that's interested. As I stated my 93 would run rough, misfire, sometimes would quit, sometimes wouldn't start back after driving a few miles. And especially when I kicked it down. Changed the MAP sensor. That did seem to make it run a little better at normal speeds. Changed the ICM today. Drove it and it ran fine until kicking it down. However, it still idled and started back correctly. Put a bottle of Lucas in it, 10 gallons of 93 octane, drove the dog crap out it for about 75 miles. High speeds when I could. It runs like brand new now.
7th Gear
Joined: Jan 2024
Posts: 7
Likes: 0
I Know this is old and I have no clue if you will still respond but I'm having a similar issue did just replacing the icm and or the ignition coil fix it or was the Lucas oil that fixed the dying specifically? if so what kind of Lucas, like injector cleaner or something else, thanks.