I'll try to keep it short. Got gas, went to start, nothing. No click, no fuel pump prime, security light on. Already have a remote starter relay, so it's not a heat soaked starter, figured that one out a while ago. Walked home to get other key(only a few blocks luckily), car started right up. Figured key went bad somehow. Back at home, BOTH keys start the car. From much searching and reviewing the factory shop manual it seems that there are two potential problems that would cause the car not to crank. One, the lock cylinder could not be reading the key's resistance correctly. Installing the correct resistor in the wires between the lock cylinder and the actual VATS module would fix that problem. Or, two, a bad VATS module. If that's the case, the resistor in the wires would NOT fix the problem. Best I can figure out, a simulator like the one from bakerelectronix spliced into the wire going to the ECM (if that's where it goes) would enable fuel but not cranking. Enabling cranking comes out of the VATS module. The car would still not crank if I had a bad VATS module. The manual says the VATS module grounds the starter enable relay. If I were to connect the correct terminal of that relay to ground, would the combination of those two completely bypass the lock cylinder and the VATS module? There are only 3 outputs from the VATS module, ECM, starter enable relay, and security light. If I have this figured out correctly, the simulator would take care of the ECM, and properly wiring the starter relay should allow the car to crank. The VATS module then is doing nothing but controlling the security light, and the right resistor would take care of that. Do I have this right, or close?

 

Anybody? Where are all the experts out there?

 

you can completely disengage it in the chip, and then just cut the vats module out of the circuit.

Your way sounds pretty interesting though I think it would work, but I'm not going to say that it will work because I'm not sure.

 

Having it disabled in the PROM would allow fuel but I don't think the car would crank. The starter enable relay is wired to the VATS module. The VATS module grounds that relay, so with no VATS module in the car something still has to be done with the relay.

 

You could bypass the starter kill with a jumper from the yellow wire in the ignition harness to the tan w/ white stripe in the center console.

 

I'll have to look into that, but now we're getting somewhere.

 

You can do 1 of 2 things here. The starter enable relay is located behind the drivers side kick panel. You could manually splice the 2 wires together and eliminate the relay or you can add your own switched 12 volt signal to the relay signal side to kick the relay on. That is what I am doing for a poor mans antitheft(kill switch) Sorry I don't know the wire colors for you but it wouldn't be hard to find them just search for wiring diagrams.

 

Good page of disabling VATS forever.. http://www.vatssucks.com/
step by step, the starter enable relay, the "chip" in the key and the FUEL enable relay.. check it out.
you got wiring diagrams and much more for making VATS go away at that page..

 

just got a car from california no vats key its tbi so i slammed a 88 caprice computer and prom into it and everything is all good no prom to burn no wires to splice simple plug and play