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Discussion Starter · #1 ·
I have a 1998 GMC Sierra 2 Wheel Drive 5.7 Liter engine. When I start it up it shuts off right after without me touching the key. I replaced the ignition module and fuel pump relay, ignition coil. If I leave it alone for 20 to 30 minutes it starts up like nothing ever happened. No check engine light or service engine light shows up. All this happens maybe once or twice a month.

I just change the plugs recently but I've been having this problem since November 2006. Any advice will be appreciated.
 

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Sounds to me like it could be the fuel pump, but I would think it would happen more often.

What are the conditions outside when this happens? Cold, hot, humid, raining, dry?

Is the engine hot, or cold, or does it matter?
 

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Discussion Starter · #3 ·
does't matter what the weather is,it usually happens when its cold[not the temperature]either in the morning or when i get out of work it just happens not the fuel pump
 

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Same Problem

I had a 98 Chevy silverado ext cab and i had to replace the fuel pump twice, the "new" pump they put in was faulty also! Just a thought...
 

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sounds to me to be a sensor of some type or maybe the pcm/ecm. when it happens try to read the codes maybe, and if it doesnt go into test mode then your pcm/ecm is shot. for the most part it sounds like an electrical prob most likely like a sensor. to check for fuel pump just listen to the pump when u turn the key on but dont start the engine. if the pump stops then it reached max preasure, and chances r u can rule that out as a start up problem. also dont forget to wire chase, u might have some bad connections or even some bad relay switches.:redface:
 

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Big wheel keeps on turning

Let's stop the wheel 'o fortune parts swapping and do a little investigating. Lucky you the truck won't start for 20-30 minutes. During that time you want to check for the basics: air, spark, fuel, timing and compression. Any one of those items will keep your truck from starting. Since your truck runs most of the time you can skip air and compression, but you've got to drill down on the other three. Spark is an easy test. Timing is a tad more difficult because you have to have a timing light with you, so put it in the truck for the next episode. A simple fuel test would be to turn the ignition on and observe the TBI and see if gas sprays from the injector during operation of the throttle. A more accurate test would be a pressure gauge. btw you did mention if it cranks during this no-run period. If you want to take another spin at the wheel, then I would try either the fuel pump or as a wild guess the ignition switch..... Keep us posted. Let us know what's working and whats not. Together we can figure it out.:great:
 

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Stop Guessing Maybe?

why don't you just go to schucks, autozone, cragen's, pep boys, advanced auto parts, napa, and any of those stores will scope the obd2 with scanner for codes? nobody charges for this anymore. and they'll gladly tell you what the code's about and what to replace?
http://www.troublecodes.net/GM/
http://www.2carpros.com/topics/stalls.htm
http://www.2carpros.com/topics/stalls.htm
http://www.2carpros.com/topics/starts.htm
as a general observation, you either have a lose wire in a harness, or humidity collection in one of the vital sensors, thanks to modern engineering, many of those are. we had an eclipse like that - sucker did not like parking outside, and plain won't start.
 

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Check the fuel pump regulator, sometimes they will stick and the gas that is in the lines is what starts the truck untill it runs dry.
 

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Is there not some safety feature like an oil pressure switch that will shut the fuel pump off if the engine is not running? Perhaps the fuel pump primes, the truck starts, but the fuel pump does not start pumping because it thinks the engine is not running? Put a volt meter on the pump wires, and see if it is running when the truck is running.
 
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