C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1986 corvette not starting sometimes

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Old Mar 5, 2026 | 06:22 PM
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Originally Posted by SSlomaro410
10-4. I’m planning to order the 15 resistors and go about it that way then maybe order the bypass once I figure out which one I need. Just trying to eliminate this second ignition since it’s now started to give me problems. Have you ever seen the red button in my most recent comment on here?
There's no reason for ordering the 15 resistors. Use a meter and check the insert in the key. Do it a couple times to be positive of the value but there's no need for a package purchase.
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Old Mar 5, 2026 | 06:25 PM
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Originally Posted by WVZR-1
There's no reason for ordering the 15 resistors. Use a meter and check the insert in the key. Do it a couple times to be positive of the value but there's no need for a package purchase.
The key is frozen in the ignition. I tried reading from the wires coming out of it. Tried getting my leads to the pellet on the key. Couldn’t get it. I’ve thought about breaking this ignition but the car currently runs with it 90% of the time so I don’t want to do that. If you have another idea I am all ears. The resistor kits only a few bucks
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Old Mar 5, 2026 | 08:32 PM
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This makes me wonder if the key is in any position but off hence the “key” is stuck???

Nothing more to add but…this might help.
https://www.corvetteforum.com/forums...post1594754928
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Old Mar 5, 2026 | 08:37 PM
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Originally Posted by stew86MCSS396
This makes me wonder if the key is in any position but off hence the “key” is stuck???
Nothing more to add but…this might help.
https://www.corvetteforum.com/forums...post1594754928
I 100% think it’s in a different position that isn’t off. I’ve got a very slow battery drain and while idk if it could be this. In my mind I can’t without a doubt say that this isn’t some of the draw.
Thanks for the reply
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Old Mar 7, 2026 | 08:00 AM
  #25  
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Originally Posted by NickPSI
Its a pretty specific number that the conductors and the ignition switch case will add ohms to
Think about this. No abnormality will lower impedence with the exception of a short which it is unlikely you would have. Any problem with the wires or the contacts that touch the key would only raise resistance. Resistance can only add it.
It must be the #1 key. I have 523 which is #2.

"Yeah measuring from the wires I’m getting .401k or 401 ohms" That is exactly a #1 key
.

Last edited by Vets-Vet; Mar 7, 2026 at 08:07 AM.
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Old Mar 11, 2026 | 12:08 PM
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If you don't have code 46, the "no start" has nothing to do with that key, resistance, wires, the button in the console, or anything else.

The SECURITY light has no association with "VATS" or cranking, or fuel enable in a 1986-1989.

I would double-check that you do or do not have Code 46. Code 46 will only be present if the "resistance" is currently not correct. Code 46 is not a stored code. If it didn't start, then it does, and you check for Code 46 to see if that was the cause, Code 46 will not be there from the prior event.

Get a $23 timers.shop VATS eliminator Signal Generator. It connects to (3) wires all available at the VATS module behind the passenger side breadbox, or at a connector under the RH dash. Eliminates any "VATS" problems or misdiagnosis permanently.



EDIT: Where do the wires from that button under the ashtray go? That could be a "Ghost Switch". Ghost Switch systems are normally incorporated into an existing switch that needs to be manipulated after key=on to activate a circuit that allows the engine to crank or start. These devices are usually a relay array that latches upon activation, and resets when the key is turned off. If that button goes to a relay or relay array, figure out what car circuit the relay(s) are interfaced into.

Personally, I interface my ghost switch systems into the ECM "turn on" wire, usually a pink/blk. The indication to the driver of the ghost switch status is the Service Engine Soon light. If the key is on, but the SES is off, the ghost switch hasn't been activated. Something to know about. The "hidden button" used to do 'something'. If I was working on a car with the history and issues yours has, I'd want to know what that 'something' is/was. .

Last edited by IHBD; Mar 11, 2026 at 12:37 PM.
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Old Mar 11, 2026 | 01:00 PM
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An '86 had two VATS issues and it seems your car suffers from both, 1) the cylinder and key blade length created issues(your stuck key), cylinders and keys were changed and covered by TSB if issues required, 2) Number 1 VATS resistance had intermittent crank issues and the #1 resistance was removed from service I believe after '86 production. I would imagine the issue was actually in the 'module'.

What do you have for a cylinder now? A brass work key with a VATS cylinder or maybe a GM correct blank being used?

If a #1 bypass is used, might you still have issues? Maybe. IHBD's mention of the 'timers shop' eliminator is a very valid suggestion.
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Old Mar 11, 2026 | 01:17 PM
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Originally Posted by IHBD
If you don't have code 46, the "no start" has nothing to do with that key, resistance, wires, the button in the console, or anything else.

The SECURITY light has no association with "VATS" or cranking, or fuel enable in a 1986-1989.

I would double-check that you do or do not have Code 46. Code 46 will only be present if the "resistance" is currently not correct. Code 46 is not a stored code. If it didn't start, then it does, and you check for Code 46 to see if that was the cause, Code 46 will not be there from the prior event.

Get a $23 timers.shop VATS eliminator Signal Generator. It connects to (3) wires all available at the VATS module behind the passenger side breadbox, or at a connector under the RH dash. Eliminates any "VATS" problems or misdiagnosis permanently.



EDIT: Where do the wires from that button under the ashtray go? That could be a "Ghost Switch". Ghost Switch systems are normally incorporated into an existing switch that needs to be manipulated after key=on to activate a circuit that allows the engine to crank or start. These devices are usually a relay array that latches upon activation, and resets when the key is turned off. If that button goes to a relay or relay array, figure out what car circuit the relay(s) are interfaced into.

Personally, I interface my ghost switch systems into the ECM "turn on" wire, usually a pink/blk. The indication to the driver of the ghost switch status is the Service Engine Soon light. If the key is on, but the SES is off, the ghost switch hasn't been activated. Something to know about. The "hidden button" used to do 'something'. If I was working on a car with the history and issues yours has, I'd want to know what that 'something' is/was. .
when I traced out those wire they seem to go through the fire wall but can’t say for certain yet. Hadn’t had time to finish tracing them. I’ll look into what you sent me and probably order it to see what happens. Thanks for the insight
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Old Mar 11, 2026 | 01:18 PM
  #29  
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Originally Posted by WVZR-1
An '86 had two VATS issues and it seems your car suffers from both, 1) the cylinder and key blade length created issues(your stuck key), cylinders and keys were changed and covered by TSB if issues required, 2) Number 1 VATS resistance had intermittent crank issues and the #1 resistance was removed from service I believe after '86 production. I would imagine the issue was actually in the 'module'.

What do you have for a cylinder now? A brass work key with a VATS cylinder or maybe a GM correct blank being used?

If a #1 bypass is used, might you still have issues? Maybe. IHBD's mention of the 'timers shop' eliminator is a very valid suggestion.
I’ll most likely get the eliminator but also the #1 bypass. Still trying to confirm I have #1. Currently I have just a standard looking ignition with what’s to be a blank key that’s cut. Looks about as basic as it gets
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Old Mar 11, 2026 | 04:59 PM
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If you have the downtime might consider getting the vats deleted from the computers memcal. I update the tune as well .

https://tunedperformance.org/store/p/gm-vats-delete
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Old Mar 12, 2026 | 01:03 AM
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A: You have #1 key resistance. This is a problem. There is no sense at all to get the bypass #1 resistor because you will still have problems with #1. As WVZR said, GM abandoned the #1 resistance for the remainder of VATS / Passkey I which was used through 96 in Corvette and later in other carlines. You have to abandon the VATS module. Either B or C below.

B: The timer.shop deal works. When you have it in hand report back, we can go over where to interface it to. IIRC the Fuel Enable signal wire in a 1986 is a different color than the dk blue of later years. WVZR has access to 1986 wiring schematics, I don't. Perhaps he will share with us the FE wire color.

C: Have Tuned performance remove VATS from your memcal. He's been on here and thirdgen.org for a long time. He knows what he's doing.

You will keep using the key and cylinder you have now. No reason to change it. The key and cyl under the dash will come out and go in the bin.

Last edited by IHBD; Mar 12, 2026 at 01:08 AM.
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