OT. 95 GMC

danmcdonald · May 14, 2013

I have a 95 gmc pickup with a 350 throttle body. It will start then die about a minuet later. It already has new fuel pump and injectors. Any ideas? Thanks

RandyB(MI) · May 14, 2013

Plugged converter or exhaust somewhere. Has it been sitting idle for any length of time? Rodents etc can plug exhaust and air filter box.

Determined · May 14, 2013

Oil pressure switch and relay controls power to fuel pump after ecm runs initial prime cycle for starting.
Filter plugged.
Ground wire to fuel pump connection corroded.
Idle air control.

danmcdonald · May 14, 2013

It has only sat a few weeks I have the air filter off of it now its ok I did also replace the fuel filter. Thanks

ASEguy · May 15, 2013

How it dies and can it be restarted immediately would be necessary information. Too little to go on.

danmcdonald · May 15, 2013

After it dies it will restart. Thanks

Revredneck · May 15, 2013

Give the ground wires at the front of the intake manifold a good look, especially if it has one on the thermostat housing (it corrodes there, making a bad connection). I always move that one over to the intake manifold bolt where the other ground is. I've fixed a lot of weird problems on those trucks by this one, simple fix.
Good Luck and God Bless

Bob · May 15, 2013

"Oil pressure switch and relay controls power to fuel pump after ecm runs initial prime cycle for starting."

NO it doesn't.

Oil pressure switch PARALLELS the fuel pump relay, which is operated by the ECM when engine rotation is detected. Oil pressure switch is only a BACKUP if the relay circuit fails. Extended cranking will result 'cuz of the delay in the fuel pump being activated... only when oil pressure builds up.

Bob · May 15, 2013

Put a sparktester and a fuel pressure gauge on it and see if it loses spark or fuel pressure when it shuts down.

To check fuel pressure, you will need an adapter to tap into the fuel line at the filter or at the back of the TBI unit.

Dr. Walt · May 15, 2013

Dan:

Several years ago my '88 GMC pickup exhibited the same symptoms. After trying everything else, I loosened the exhaust pipes where they connected to the manifolds, and the engine started and ran fine. In my case, it seems that someone was "playing games" and had stuffed a tennis ball up the tailpipe - the back-pressure killed the engine after it started.

This is something you might want to check - GOOD LUCK ! Doc.

ASEguy · May 16, 2013

If it restarts immediately after dying AND dies on decel I would remove and clean the AIS (Air Idle Speed) motor on the throttle body and the throttle body throat off the vehicle. This assumes it doesn't kick and buck prior to dying which coud be EGR hanging open. Again, too little information.

OT. 95 GMC

danmcdonald

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RandyB(MI)

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Determined

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danmcdonald

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ASEguy

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danmcdonald

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Revredneck

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Bob

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Bob

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Dr. Walt

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ASEguy

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