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Author Topic: Fuel problems I think  (Read 4743 times)

Offline BU113TZ

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Fuel problems I think
« on: December 22, 2009, 02:39:11 am »
I have a 1987 GMC sierra 2500 4x4 its TBI and i cant get it up and running ive replaced the fuel filter, fuel selector valve, MAP sensor, oxygen sensor, Fuel tank selector switch, Oil pressure Switch, Tore the catalytic converter off and still wont run if any one has any ideas please let me know. The fuel tank switch only activates the pumps when im holding it down and it still wont run while im holding the switch
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Offline Irish_Alley

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Re: Fuel problems I think
« Reply #1 on: December 22, 2009, 03:17:33 am »
couple questions a are you getting spark. b are you getting fuel up to the tbi? also when was the last time for a time up plugs wires.
isn't there a sensor/relay under the bed for the tank switch
« Last Edit: December 22, 2009, 03:42:10 am by Irish_Alley »
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Offline BU113TZ

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Re: Fuel problems I think
« Reply #2 on: December 22, 2009, 04:41:54 am »
Well im getting spark just not getting fuel but ya i replaced the fuel pump relay and it still isnt working so i dont know im thinking of taking it to a repair shop even though they charge like 80 bucks an hour
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Offline Irish_Alley

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Re: Fuel problems I think
« Reply #3 on: December 22, 2009, 05:07:12 am »
not talking about the relay but the selector under the bed both tanks run into it then go to the engine
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If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline BU113TZ

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Re: Fuel problems I think
« Reply #4 on: December 22, 2009, 07:21:06 am »
Ya the (fuel selector valve) its brand new i replaced it already
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Offline Captkaos

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Re: Fuel problems I think
« Reply #5 on: December 22, 2009, 09:33:21 am »
Take the supply line off the back of the TBI, or after the filter and see if you are getting fuel to there.  If you are, I would suspect the regulator in the TBI, or bad injectors, but there are other test to do before you start throwing parts at it.  You can also crimp off the return line at the braided section and see if anything changes.

The pump will only prime with the switch on, once it reaches pressure it turns off.  It only runs with the engine running.
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Offline DnStClr

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Re: Fuel problems I think
« Reply #6 on: December 22, 2009, 11:43:10 am »
Quote
The fuel tank switch only activates the pumps when im holding it down and it still wont run while im holding the switch

Why do you have to hold the switch in position? It has positive detents so it's not necessary to hold it. FYI-Capt Kaos did a writeup on rebuilding the switch. See the tech articles section.
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Don
87 Chevy Silverado

Offline VileZambonie

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Re: Fuel problems I think
« Reply #7 on: December 22, 2009, 06:31:43 pm »
Don, where've u been? I agree why do you have to hold the switch? Bad connections?
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