I worked out a bunch of bugs and now the car will start but it shuts itself right back off, it sounds like it just cuts fuel or spark, just as if you where to turn the key off. Is there something in the computer that needs to be disabled due to not using a vats key anymore?

 

The VATS will have to be disabled in the PCM or a bypass module used.

 

Thank you.

 

Does anyone know what the voltage signal from the BCM to the ecu for the fuel enable is supposed to be?

 

It needs to be a 5v 40-60Hz "PWM (pulse width modulated)" signal. You would need some fancy electronics to emulate this (a 555 timer, a couple resistors, a capacitor).

Alternatively, you can disable "VATS" in the PCM program and it will ignore the fuel enable pin from the BCM.

If it is a 1997 or 1998 LS1 PCM, it will also exhibit the same symptoms if the ROM gets corrupted. You will also see a P0601 code from the computer after trying to start it.

 

Thank you. I found that out last night and I have a small pile of electrical crap in front of me now. My guy who has HP tuners is out of town until next week and I need the car out for this weekend.