1990 Stops running
Thread Starter
3rd Gear
Joined: Oct 2024
Posts: 3
Likes: 0
1990 Stops running
My 1990 with the L98 has a difficult to find problem. Runs fine then will just stop. Not stumbly or rough running. Just shuts off. Crank it and it will not restart. By the time I get tools to figure out what is wrong it starts up fine. Twice already I went and got the trailer to bring it home. When I got back with trailer, started fine and drove it onto the trailer. Thought it may be the fuel pump so installed a new one. It did need a new pump, at 143,000 miles but that didn't solve issue. Hooked up fuel pressure gauge so I could see it while driving. When it quit again the fuel pressure remained fine, So not a fuel issue. Thinking it is spark, but by time I get stuff to check, it starts again fine.
Anyone have ideas before I just start replacing stuff? Going to drive it till it quits again and hope to check for spart before it fixes itself again. But afraid to take it anywhere but on my street..
Ed
Anyone have ideas before I just start replacing stuff? Going to drive it till it quits again and hope to check for spart before it fixes itself again. But afraid to take it anywhere but on my street..
Ed
Melting Slicks
Joined: Jul 2005
Posts: 2,207
Likes: 302
That would be my first suspicion too based on the symptoms.
Immediate cut out like that is typically spark related. If fuel cuts out, more often than not you'll get some stumbling and sputtering before it dies.
Just make when you replace it you use a good thermal compound under it. Heat kills these things. Do not use dielectric grease.
Get a Delco too. Both for the reliability and compatibility with the stock tune. It's a long story, but if you search on spark latency you can find what I'm talking about. Aftermarket modules can throw off the ignition timing.
Immediate cut out like that is typically spark related. If fuel cuts out, more often than not you'll get some stumbling and sputtering before it dies.
Just make when you replace it you use a good thermal compound under it. Heat kills these things. Do not use dielectric grease.
Get a Delco too. Both for the reliability and compatibility with the stock tune. It's a long story, but if you search on spark latency you can find what I'm talking about. Aftermarket modules can throw off the ignition timing.
Thread Starter
3rd Gear
Joined: Oct 2024
Posts: 3
Likes: 0
I will replace the module. But on other cars with the HEI ignition, when module went it was gone. Car would not restart at all, even after sitting. Last module in this car was a NAPA brand. Maybe that could be it. Will get a new one and drive local until I feel the car will keep running. Want to get to enjoy the top-down driving before winter sets in.
Melting Slicks
Joined: Nov 2016
Posts: 2,253
Likes: 3,074
From: So Cal
2023 C4 of the Year Finalist - Unmodified
I agree with the OP that Ignition Modules usually die and stay dead. I've had a handful of pick up coils cause a stall, but they restart. For a few weeks or so, then they die for good. Tough to find the actual problem when it restarts.
Measure the resistance of the pick up coil. Should be around 840 Ohms, and no change when wiggling the wires. If higher, it is probably "dying". Replace it.
Measure the resistance of the pick up coil. Should be around 840 Ohms, and no change when wiggling the wires. If higher, it is probably "dying". Replace it.
Melting Slicks
Joined: Jul 2005
Posts: 2,207
Likes: 302
I agree with the OP that Ignition Modules usually die and stay dead. I've had a handful of pick up coils cause a stall, but they restart. For a few weeks or so, then they die for good. Tough to find the actual problem when it restarts.
Measure the resistance of the pick up coil. Should be around 840 Ohms, and no change when wiggling the wires. If higher, it is probably "dying". Replace it.
Measure the resistance of the pick up coil. Should be around 840 Ohms, and no change when wiggling the wires. If higher, it is probably "dying". Replace it.
https://www.corvetteforum.com/forums...-replaced.html
Thread Starter
3rd Gear
Joined: Oct 2024
Posts: 3
Likes: 0
I have an aftermarket DUI distributor that came with a DUI module. Replaced with different kind like 10 years ago. Put the NAPA one in this spring. Wonder if that is part of the problem. Will check color of wires on pole piece this weekend.
Ed
Ed
