LT1Chad

Hello all new to the form.

I've been helping a friend with his 90 C4.
He parked it in his garage one day and the next it would'nt crank.
I used a VAT's pypass module and now it cranks but won't start.
I have'nt checked the fuel pressure (no gauge) but the rails do have pressure on them.
You can spray starting fluid into the TB and it will start and run as long as you keep spraying.
1. Could this still be a VAT's related problem?
2. Where is the VAT's decoder module at on a 90?
3. What is the wire color/pin location from the VAT's signal at the ECU?

Thanks for any help.

Pete K

You have a fuel problem

jfb

Connect a noid light (available at a parts store) across an injector plug from the wiring harness and see if it pulses while cranking. You can also use a low power 12v lamp. If you can crank, the VATS may be ok, but still possible that the VATS module is not telling the ECM to pulse the injectors, although unlikely. Check the inj1 and inj2 fuses.

LT1Chad

Thanks for the replies.
I'll check for voltage at the injectors.

From what I understand is that the VAT's decoder module has two wires leaving, one to the ECM and the other to the strarter relay.

Thats the reason I'm wanting the pin out on the ECM, so I can see if its getting a signal from the VAT's system.

The car has set for a year.

LT1Chad

Where is the VAT's module on the 90 located?

LT1Chad

I talked to my friend today and he did'nt bother to tell me that he had the starter relay bypassed.!! LOL
Sorry for the confusion.
He does have the correct VATs bypass module from GMP pluged into the harness under the dash. I checked his key for its value today myself and it's the correct module.
So it has yo be some other place in the VAT's system.
So I realy need to know where the module is.
Does anyone have a wiring diagram for the 90 Vette.
Thanks again.