C4 vette
Thread Starter
Intermediate
Joined: Jul 2021
Posts: 27
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From: Paragould, Arkansas
C4 vette
Ok my 89 c4 has a problem I think is an ongoing with a lot of them on cold starts the motor won't turn over. Full power to everything. It's like moter is locked. So I read on the forum common problem. Said I needed a new key with new chip . so I went to my local marler key shop. He cut me a new chip key with propper vat code. Didn't help. So I've read that a vat bypass will take care of it. Do I took it to a Corvette mechanic today and he told me it doesn't sound like it needs a bypass but he had no clue as to what cud b wrong. So anybody out there have a solution for thus??? II will finally start with a lot of clicks and nothing at all. Thanks in advance
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Ok my 89 c4 has a problem I think is an ongoing with a lot of them on cold starts the motor won't turn over. Full power to everything. It's like moter is locked. So I read on the forum common problem. Said I needed a new key with new chip . so I went to my local marler key shop. He cut me a new chip key with propper vat code. Didn't help. So I've read that a vat bypass will take care of it. Do I took it to a Corvette mechanic today and he told me it doesn't sound like it needs a bypass but he had no clue as to what cud b wrong. So anybody out there have a solution for thus??? II will finally start with a lot of clicks and nothing at all. Thanks in advance
Your Corvette mechanic probably doesn't want to do anything so that is the next problem to fix. Another tech.
Have you tested the battery? How is the alternator? I always check the two at the same time since one can screw up the other. Have a real tech check for the current draw or if you feel like it, take the starter out for testing or better yet, rebuilding where they will open it up and check everything.
Melting Slicks
Joined: Jan 2014
Posts: 2,192
Likes: 381
From: Lunenburg MA
Finding a decent mechanic that wants to work on older cars can be tough. Time to buy a 12V test light and dig in!
First I'd make sure it's not the starter. Put a test light on the smaller wire and see if it lights when the key is turned. If not, then I'd check the neutral safety switch on the shifter. Both purple wires should light when the key is turned. Next time it does that, try moving the shifter a bit (assuming it's an auto). If it's not that, I'd try bypassing the starter enable relay which is behind the dash to the right of the DIC. That relay is what VATs uses to disable the starter. They can go bad. To temporarily bypass either the neutral safety or the enable relay use something like a paper clip to short the two heavy purple wires.
First I'd make sure it's not the starter. Put a test light on the smaller wire and see if it lights when the key is turned. If not, then I'd check the neutral safety switch on the shifter. Both purple wires should light when the key is turned. Next time it does that, try moving the shifter a bit (assuming it's an auto). If it's not that, I'd try bypassing the starter enable relay which is behind the dash to the right of the DIC. That relay is what VATs uses to disable the starter. They can go bad. To temporarily bypass either the neutral safety or the enable relay use something like a paper clip to short the two heavy purple wires.
Le Mans Master
Joined: Dec 2004
Posts: 5,488
Likes: 1,352
You need to diagnose it. What exactly does it do when you turn the key ? Nothing ?? If it makes a click it’s more than likely a starter going bad. Let’s figure out what it’s doing and not throw parts at it though.These are relatively simple cars by today standards.
