Mechanics

WHAT CAUSES THE MOTOR TO RUN FINE FOR 10 OR 20 MINS THEN DIE?

1992 Pontiac Bonneville • 168,000 miles

It starts ok, idles ok, then drive it for 10 mins it will start missing out then die.
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Deadman606
December 5, 2011.



It could be an ignition or fuel problem. Does the car start righ back up? If not, when it doesn't start, check to see if there is spark and fuel to the engine. Also, check fuel pump pressure.

It doesnt start back up untill it's completely cooled down, I changed the spark plugs and the old one which are only a few months old had really bad carbon deposites, before I did it wouldnt start at all, Im thinking its bad gas bu Im not for sure, could it be he ignition coil packs? Or does it sound like bad gas?

Tiny
Deadman606
Dec 5, 2011.
It sounds like either a bad crank sensor or fuel pump. When it doesn't start, check for spark and fuel to the engine. One will be missing. Then we will know what circuit to focus on.

Ok that narrows it down, I did two different diagnostics and no code came up at all, whats the best way to check for spark or fuel? If a code doesnt come up does that mean the crank sensor is fine?

Tiny
Deadman606
Dec 5, 2011.
No, it could still be bad. Go to our homepage under the DIY section for detailed instruction for checking both. There is also a video for checking fuel pump pressure.

Let me know what you find.

Ok, thank you so much for your advice, it does sound like a crank sensor to me but before I assume that I will check the fuel pressure and check for spark, and yes I will definitely let you know what I find out, again thank you

Tiny
Deadman606
Dec 5, 2011.
Sounds good. Make sure you check for both when it won't start.

Look forward to hearing from you. Also, if you need a fuel pressure gauge, most parts stores will lend or rent them.

Ok, I did a spark and fuel test, and I found spark to the plugs but theres no fuel coming from the test valve on the motor, not even a little, so does that sound like a fuel pump?

Tiny
Deadman606
Dec 5, 2011.
Either a bad pump or a plugged fuel filter. Disconnect the filter and connect gauge there to see if there is pressure. If none before the filter, then the pump is most likely bad.

Awesome, thank you, I shall do that and see how it turns out.

Tiny
Deadman606
Dec 6, 2011.
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