Ok, well I have an 86 corvette and I'm tired of dealing with this problem. Basically when I go out to start the car its like the security randomly triggers and won't let the car turn over. I've tried pulling the theft fuse to see if that would help but it didn't. Sometimes it will start without a problem but when it does do it, I can unhook the negative battery cable for about a minute and it will start right up. Any help on how to fix it will be appreciated.

 

You need to check out your VATS (vehicle anti theft system) system.
The VATS module measures the resistance of the pellet in your ign key and if it is within 4% of the assigned value it closes the start enable relay which allows the ign sw start contacts to supply power to the starter solenoid to crank the engine. It also allows the ECM (electronic control module) to pulse the injectors.
When your vette won't crank, that is when you need to start diagnosis. Unplug the clutch safety switch (gear selector switch if automatic at the base of the gear shift) and jump the connector. Measure the voltage on the jumper when the ign sw is in crank position. You should have 12v and the starter should crank. You can jump 12v to this jumper and the starter should crank the engine. Check the resistance across the clutch safety switch when it is activated, it should be the same as touching the ohmeter probes together. If no 12v on the jumper, then remove the kick panel above the drivers feet and find the two wires coming from above the steering column that go to a 2 pin connector and unplug. Insert the key and measure the resistance across the wires from the steering column. It should measure the same as the ign key pellet. If not, you have worn contacts in the ign lock that make connection to the key pellet. You then need a new ign lock which has new contacts that connect to the key pellet. You can temporarily bypass VATS by connecting a resistor the same value as your key pellet across the two pins in the wiring harness that the wires from the steering column plugged into. You can buy some resistors from radio shack to make up a combination that is within 4% of the assigned value. It is also possible that the start relay contacts are intermittent and this can be found by measuring the voltage on the input and output wires on the relay when it is activated. It of course should pass 12v.

 

Ok, thanks I'll try that tomorrow and see what happens. Would that explain why I can disconnect the battery for about a minute and then it will start?

 

If the VATS doesn't see the correct resistance it will not allow another start attempt for 6 minutes. If you disconnect the battery, that resets the ECM and you get another attempt to start your car right away. My money is on a worn ign lock contacts or worn clutch safety switch which become intermittent, sometimes it starts, sometimes it doesn't.

 

Alright well mines automatic so clutch safety switch is out of the question. How much is it going to cost me if it is the contacts?