Help!
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1st Gear
Joined: Jul 2021
Posts: 1
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Help!
Recently purchased a 1998 coupe with some known issues. After several weeks of running grounds and looking at wiring diagrams I thought the issue had been resolved but it reared it's ugly head today. From the beginning the car would start, run, and drive but at any time would simply die while driving. After a starter and ignition switch replacement nothing would work. The car would turn over but nothing else. After several nights of running grounds found that the ground cable for the battery was the culprit. A new ground cable and she started right up and all seemed good until today. Went out to drive the car and it started up and ran like a top. But about 4 seconds of running it died. Then would not start. Pulled key for 10 seconds and it started right up but then 4 seconds later it died again. I'm about at my last care for the car and am contemplating on selling it. Any ideas of what could be causing this issue before I do?
Le Mans Master
Joined: Dec 2017
Posts: 5,535
Likes: 3,277
From: Virginia
2021 C5 of the Year Finalist - Modified
St. Jude Donor '21-'22
First, welcome to the forum! Second, you will likely get the best responses to your question in the C5 Tech section. With that said, I'll give what advice that I can. The first thing that you're going to want to do is pull the codes from the DIC. That should point you in the right direction. Once you find out what codes you have, we can help you better. For now, my guess is that you have a fuel sending issue. Your fuel injectors could be clogged, or the fuel pump is clogged or having issues. If that is the case, you could try putting techron in the tank. However, if the car only runs 10 seconds ata time that might not work. You might also want to check your fuel filter. There are other possibilities, but without the codes, I'm just guessing. You mentioned pulling the key for 10 seconds. Is the car telling you to do that? If so, that is related to the column lock issue. That is something else altogether. If that's the case, you needs a column lock bypass or LMC5. Good luck with your issue. Be sure to post up your codes here after you pull them.
Melting Slicks
Joined: May 2014
Posts: 2,522
Likes: 108
The corroded ignition switch contacts can cause all kind of issues like you mentioned, search ignition switch on the forum, i have seen great write up advice posted on here about this condition - GOOD LUCK !
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,319
Likes: 3,927
From: Cape Coral, Florida
Recently purchased a 1998 coupe with some known issues. After several weeks of running grounds and looking at wiring diagrams I thought the issue had been resolved but it reared it's ugly head today. From the beginning the car would start, run, and drive but at any time would simply die while driving. After a starter and ignition switch replacement nothing would work. The car would turn over but nothing else. After several nights of running grounds found that the ground cable for the battery was the culprit. A new ground cable and she started right up and all seemed good until today. Went out to drive the car and it started up and ran like a top. But about 4 seconds of running it died. Then would not start. Pulled key for 10 seconds and it started right up but then 4 seconds later it died again. I'm about at my last care for the car and am contemplating on selling it. Any ideas of what could be causing this issue before I do?
Last edited by C5 Diag; Jul 23, 2021 at 06:15 PM.
Race Director
Joined: Oct 2004
Posts: 12,795
Likes: 4,614
After following C5Diag's suggestions, I would try 1 more thing. Disconnect the battery FIRST. Then turn the key back and forth from 'lock' to 'start', maybe 40 or 50 times in rapid succession, or until your wrist is killing you 
This will sort of clean your ignition switch contacts. To as good as a new switch, but if this maneuver 'fixes' the problem, you should think about buying a new switch. Hope this helps, and good luck....
This will sort of clean your ignition switch contacts. To as good as a new switch, but if this maneuver 'fixes' the problem, you should think about buying a new switch. Hope this helps, and good luck....
