I have been back and forth on this project over the years. My son drove the car daily and my dad had it for after that. 93 z28, 4l60(non e) the LT1 engine was bad when we got it and it had a missing transmission. It got a forged 8 upgrade. Stock heads and cam. Car does have a tune, stock 22lbs injectors. Stock transmission replacement. Dad passed away in 2019. The car was rarely driven but cranked and ran up to temp 2 times a month. I had been working off with not much time to work on it. The car got to where it didn't want to crank and it sat. Last year I put a new starter and Fuel pump in it and got it to crank, ran it around in the yard for over a hour. Next it day wouldn't crank.

I think it is a vats issue. When my son had it he said he got a custom tune for it and vats was suppose to be deleted, but from time to time he would have issues with it cranking. Then it would work again for awhile. I though maybe it was the vats key read issue. Got my meter out and read the key and ordered the correct plug in read resistor. The car still wouldn't crank. The car sat for a few more months. I am finally where job wise and weekend wise I am off on weekends and can work on the car like I need too.

Currently it still has the bypass key resistor and today I jumped the starter relay behind the glove box (two yellow big wires on one side and on the other side one big green wire with a single small wire. Either of the big yellow wires to the green wire would all the starter to engage. But I am not hearing the fuel pump fire up. I am going to have to hot wire it to make sure it is still in a working state or if I need to get a new one. Is it possible the vats box it's self has went out. If it has what is the best course of action?

 

Heads up…. Hardly anyone comes here any more. Maybe a half-dozen LT1 enthusiasts drop in once in a while.

Always risky assuming the 93 is identical to the 94 and up models. For the theft deterrent relay, the yellow wire from the ignition switch passes through the
clutch start switch (manual) or transmission range switch, so you might want to temporarily bypass that switch.

To temporarily power the fuel pump and check its operation, there should be a fuel pump prime connector near the ECM. It’s there 94 and up, hopefully the 93 is similar:

http://shbox.com/1/fuel_pump_prime.jpg

The PASS-Key II (VATS) system theft deterrent module (TDM) sends a “fuel enable” signal to the ECM. If that signal is not received the ECM shuts down the injectors, not the pump.

4th Gen LT1 F-Body Tech-PassKey/VATS

Free download of 1993 factory service manual, courtesy of member Gary Doug:

https://www.mediafire.com/?40mfgeoe4ctti

 

This sounds interesting. I may want to get involved with it. Can you describe in more detail? Some of you comments sound cunfusing.