1988 GMC Sierra Fuel Pump?

RIVERRAT45750

MEMBER
1988 GMC SIERRA

Engine Mechanical problem
1988 GMC Sierra V8 Four Wheel Drive Automatic 118k miles

Electrical systems engage fine, starter engages and performs properly, yet engine does not start. When it is above 50 degrees or so, it can be "coaxed" into starting, but it is still reluctant. Once it has been started, it will start right up again, with or without any driving. But once it sits overnight, it becomes reluctant to start again. Is my fuel pump allowing the gas to drain, or is it something else?

6 Replies

JDL

MECHANIC
16,098 POSTS

Hi, how long since a tune-up? If you suspect a fuel issue, I'd use a fuel pressure gage, first. Some of the national brand autostores used to loan out a fuel pressure gage, if you don't have one. Are there any trouble codes?

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Saturday, February 27th, 2010 AT 11:31 AM

RIVERRAT45750

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K. My brother (trained mechanic) tuned it up before he passed last summer. I got it after that. No codes present when hooked up to a scanner. Will try the fuel pressure gauge. Thanks for the help!

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Saturday, February 27th, 2010 AT 11:37 AM

RIVERRAT45750

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Hooked truck to a fuel pressure guage, pressure reads about 28# with the key in, and about 55# at idle. I think this is within the normal range, but I am not sure. If so, where would I search for the problem? Thanks for any help you can provide.

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Saturday, February 27th, 2010 AT 2:56 PM

JDL

MECHANIC
16,098 POSTS

The info I looked at was, gasoline-- TBI-- fuel pressure around 10 psi. Do you have two injectors in the throttle-body, you should be able to see them spray gas?

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Saturday, February 27th, 2010 AT 3:39 PM

JASON0821

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I have a simiar problem. I got a 90 1500 305 and we changed the injectors and still nothing coming out. We tested if any volts and nothing. Could it be the ignition module? The fuel pump works the filter is fine gas comes all the way up but not spitting out the injectors. Could it be something else? I need to know because alot of us are working and we are now on one car so I need to fix the truck. Pease help me out