ROAD SIDE ASSISTANCE NEEDED - Start runs 3 seconds, shuts down

Ok I am stuck 140 miles from the house. Looking for any help.

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VATS is physically disabled with jumper in relay position - I checked and this is jumper is still in place.

Checked grounds at back of coil - they are fine.

Battery terminals tight.

Fuel pump running as it starts - cannot no hear it after that.

Starts up immediately after it shuts down.

When it shuts down it acts like you turned the key off, but it revs up a couple hundred RPM and dies. No stumbling.

Oil pressure switch cutting off power to the fuel pump?

I thought about that to. No tools with me, but the gauge is still working. I need to have someone listen to see if the fuel pump continues working.

Bad oil pressure switch maybe, fuel pump relay perhaps. How about hotwiring the fuel pump test lead to make the pump run non-stop to get you home? Would that work (anyone)?

VATS are not disabled in the PCM. I will try this next, but letting computer charge before I try this.

My question is that if VATS is bypassed, PCM should not be able to effect it correct?

jayoldschool wrote:

Bad oil pressure switch maybe, fuel pump relay perhaps. How about hotwiring the fuel pump test lead to make the pump run non-stop to get you home? Would that work (anyone)?

Might burn out the pump? I could jumper it to see if it would run though. I also think the car would stumble as it ran out of fuel/pressure.

From what I remember reading about the VATS system.

The PCM will shut down the fuel injectors after 3 seconds if it does not receive the correct signal from the VATS/BCM unit. It will allow the car to start and then shut off the fuel injectors.

Again if I remember correctly.

Reprogrammed PCM. Turned VATS off. Now she stays on. Crisis averted.

You guys are great! Thanks!

Glad you got it Tim. VATS is a two-piece deal and it looks like you got bit by the fuel injector piece.

Just to clarify on the oil pressure switch question in case you get stuck in the future:

All LT1s WILL RUN with no oil pressure.

On the '94-95s, the fuel pump circuit is PARALLEL through both the relay and the oil pressure switch. EITHER path being intact will power the fuel pump.

Pull the fuel pump relay from the underhood fuse box and car will start as soon as oil pressure builds. Reinstall the relay, pull the connector off the oil pressure switch and the car will still run. Pull both and the fuel pump goes dead.

Got home just fine with no issues other than a flashing "security" light. Will have to pull a bulb or fuse. I have to pull the ABS light as well and update my spedo needles. So now that project comes to the top of the pile......

You can turn off VATS in PCM programming? No need for the jumper? Or do you still need the jumper for the starter circuit?

EDIT - You can disable the fuel injector cutof in the PCM. There is a bit that you can set to zero to disable it. BUT - you also need to bypass the VATS module starter relay disable.

And you need to turn off the "security" light on the dash.