i dont know if you have ever heard of this but my 90 z28 likes to not start, then 5 or ten minutes later it will fire up like nothing happened. its not the starter i already checked it. this is the 3rd car ive had like this my 92 firebird convertible and my 91 TA. let me know if u can figure it out.

 

Sounds like VATS to me.

Im pretty sure all those years had VATS.

VATS is the resistor pellet in your key. There is a sensor that senses how much resistance your particular key pellet has, and if it matches what it's expecting, it will allow you to start the car.

As the ignition switch mechanism ages and the wires taht go to the contacts taht touch the key and complete the circuit, tehy wear out, connections go bad, and things stop reading properly. Usually it will work, sometimes it wont. And when it doesn't it wont let the car restart for several minutes. It will do NOTHING. And then when the timer goes out... you can go give it another shot, and it can fire just fine.

It could be a few things, but I'd suspect that myself. Normally VATS gets more troublesome over time so the problem will likely get worse if that's what it is.


If it sounds like what I'm describing there are two fixes... one is really easy, the other is... well, up to you. If you have a multimeter, measure the resistance in the pellet on your key, and get a resistor(s) to match. Then find the two VATS wires in the dash and cut them, and splice the two resistors in line with the VATS module (you're basically bypassing the ignition switch and key entirely) and the problem is solved... except you no longer have a working anti-theft system.

You can replace the ignition switch and hope the new switch works better if you want.

 

Does the motor turn over without fireing? Or is their nothing when you turn the key?