intermittent no spark
Thread Starter
3rd Gear
Joined: Jul 2022
Posts: 3
Likes: 0
From: CT
intermittent no spark
My 94 LT-1 has an intermittent no spark.Today just for fun i took the negative cable off for about 2 hours re-connected and it started. At first i thought it might be the VAT system but i had fuel and the starter would spin.From what I found out the VAT would stop fuel and or starter operation,is that correct? Didn't try tapping the P.C.M. while it was running to see if the issue was a bad box. I have to borrow a scan tool.mine stops at 1999.Any help would be greatly welcomed.
Melting Slicks
Joined: May 2014
Posts: 2,894
Likes: 592
From: New Port Richey FL
Just a little low Tech something to check, in my own car I played the Opti switch out game chased my tail and made myself crazy.
As it turns out my problem was the cluster of wires in Right front corner of block, specifically the ICM & Coil Control/power wires. What I found after 3rd Opti and each time car would start run like a champ, but while letting car warm up I was cleaning up the wires and car shut down and each time I touched the bundle shut down.
The problem was the coil power had like 1 or 2 Strands left and the same for the ICM wires someone was tough on that harness.
$5.00 Dollars later and a harness from a donor Road Master all is well.
As it turns out my problem was the cluster of wires in Right front corner of block, specifically the ICM & Coil Control/power wires. What I found after 3rd Opti and each time car would start run like a champ, but while letting car warm up I was cleaning up the wires and car shut down and each time I touched the bundle shut down.
The problem was the coil power had like 1 or 2 Strands left and the same for the ICM wires someone was tough on that harness.
$5.00 Dollars later and a harness from a donor Road Master all is well.
Last edited by s carter; Jul 21, 2022 at 07:38 PM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
If starer engages and security light goes out it's not vats. Although car has 16 pin OBD2 type aldl connector, it's because pcm is refreshed, it is OBD 1. Car will still display flash codes. It's always best to test during failure. When you state have fuel is that injector pulse , pressure , or both? Carrying spark tester and noid light can help isolate problems when dealing with intermittents.
Le Mans Master
Joined: Oct 2004
Posts: 7,706
Likes: 485
From: Everett WA
C4 of Year Finalist (appearance mods) 2019
