No Spark
Thread Starter
Navigator
Joined: Apr 2010
Posts: 9
Likes: 0
No Spark
I have a 1995 Vette with the LT-1. I replaced the optispark unit with a new Delco unit about 6000 miles ago. The problem I'm having started about a year after replacement with me having to spin it over for about 5-10 seconds for it to start when it was hot. Now when the car idles in the driveway for about 5-10 minutes or if I go for a drive it dies and will not restart till it cools down. The temp is usually between 165 and 180 when this happens. The engine runs perfect at highway speeds and at idle. I checked the plugs when this happens and they are not getting a spark.
Advanced
Joined: Apr 2009
Posts: 55
Likes: 0
From: Soddy Daisy TN
Had the exact same problem this weekend.
Checked the codes and had an H42. Went
through the diagnostics in the FSM and seemed
it was the ICM. Have one ordered and
hope that fixes it. Might be worth checking on
yours too.
Good luck.
Checked the codes and had an H42. Went
through the diagnostics in the FSM and seemed
it was the ICM. Have one ordered and
hope that fixes it. Might be worth checking on
yours too.
Good luck.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
I have a 1995 Vette with the LT-1. I replaced the optispark unit with a new Delco unit about 6000 miles ago. The problem I'm having started about a year after replacement with me having to spin it over for about 5-10 seconds for it to start when it was hot. Now when the car idles in the driveway for about 5-10 minutes or if I go for a drive it dies and will not restart till it cools down. The temp is usually between 165 and 180 when this happens. The engine runs perfect at highway speeds and at idle. I checked the plugs when this happens and they are not getting a spark.
Idles for about 10 minutes and dies. Engine spins but NO SPARK.
Has a new GM opti-spark AND GM ignition module.
Checked all computer/engine grounds and they are clean and tight.
Preformed the tests in the GM service manual. Power AND ground to module are correct. AND the signal wire from the PCM to the module IS NOT grounded, open or going to 12+ power. Tested the circuits to the coil..which led me to think it was a bad NEW ignition module....plugged one in and NOTHING. Plugged a NEW coil in and nothing...no spark. Checked the resistance to the coil wire and it is falling in the dsescribed limits ...below 5000 ohms...which it is about 3500 ohms.
When I started it the next morning...it fired up. Shut it down and installed a good used PCM out of a donor Corvette...asme exact computer service number. Started it and it ran for a good while. Shut off teh car ...becasue I only did that was to make sure that the donor PCM would work. Removed that donor PCM and re-installed the factory original PCM. Car started and ran and after 10+ minutes...it died. Re-installed the donor PCM and NOTHING.
I am at my whits end....so any of you "guru's" who are really into this....please voice you opinions.
"DUB"
