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Old Mar 30, 2017 | 12:58 PM
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Hello. I have rescued a 1986 corvette from going to the scrap yard. The car has been sitting since 2002. I rebuilt the factory TPI engine. My problem is I think The VATS system is holding me up.
The car will not do anything when I turn the key. I have spliced a resistor into the wiring like advised by all the web sites I read. I read that the SECURITY light should come on when I turn the key to the on position. Mine dose not come on then. But when I turn the key to start the car the SECURITY light and the ABS light will come on as long as the key is in the start position.
I have worked on cars all my life but I don't know anything about this VATS.
Please Help.
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Old Mar 30, 2017 | 02:38 PM
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Use the Field Service Manual (FSM) and go through the "No Start" flow chart. I did this on my old 87 and found out that the VATS controller was bad. I ordered a used one from Vette2Vette and never looked back. The controller is behind the dash:


Here is the L98 starting sequence. Hope this helps:
http://www.corvettebuyers.com/c4vettes/l98.htm
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Old Mar 30, 2017 | 02:57 PM
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By adding the resistor to the vats ignition circuit you are only bypassing the key pellet and wiring in the steering column.

Last edited by Dt86; Mar 30, 2017 at 02:58 PM.
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Old Mar 31, 2017 | 02:26 AM
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Originally Posted by 1986TPIred
I read that the SECURITY light should come on when I turn the key to the on position. Mine dose not come on then. But when I turn the key to start the car the SECURITY light and the ABS light will come on as long as the key is in the start position.
That is only true of 1990 and later cars. They have a different security setup than the earlier cars. There are two security systems on your car. One is known as TDS (Theft Deterrent System). It will honk the horn if the door is opened while the system is armed. The other is VATS (Vehicle Anti-Theft System). It will prevent the starter from cranking and disable the injectors.

The SECURITY light is part of the TDS system. It has no connection to VATS. It should come on if the door is opened. It will flash if the door is open and the TDS is NOT armed. It will be on solid if the door is open and the TDS IS armed. The light should go out if the door is closed or the ignition is turned on.
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Old Mar 31, 2017 | 02:35 AM
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Originally Posted by corvetteronw
Here is the L98 starting sequence. Hope this helps:
http://www.corvettebuyers.com/c4vettes/l98.htm
That info has a lot of problems, such as there being a connection between the oil pressure switch and the ECM. There is none.

The ECM turns on the fuel pump relay for 2 seconds at key on and any time it sees DRPs (Distributor Reference Pulses) from the ignition module inside the distributor. The oil pressure switch is a backup to the fuel pump relay, not the other way around.
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