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Old 06-24-2018, 09:28 PM   #1
natedogg
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Fuel starvation issue? Please help.

I recently bought this 84 GMC cheap because it didn't run, needed a transmission and had been sitting awhile. Swapped in a used trans, new plugs, wires, rotor and cap. Fixed a few other things and started driving. Seem to run and drive great and then this problem showed up and has me stumped. Once the truck warms up and after a short drive it won't accelerate fast. It will speed up, but slowly. I put on a new fuel pump, fuel filter, carb base gasket and a different quadrajet that I had and didn't solve the problem. Also, I made sure the heat riser was fully open at full operating temp. Keep in mind that this truck is mostly original with a 305 and the ESC distributor still in place. However, all of the smog parts and converter are long gone. Any suggestions? Thanks for any and all help.
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Last edited by natedogg; 06-24-2018 at 09:46 PM.
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Old 06-25-2018, 07:22 AM   #2
cadillac_al
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Re: Fuel starvation issue? Please help.

When it starts running bad pull over and open your gas cap to see if there is vacuum in there. It could be a malfunctioning vent. If all the smog equipment is gone already then I would buy a Skip White distributor so you can have a normal vacuum advance.
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Old 06-25-2018, 01:47 PM   #3
kwmech
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Re: Fuel starvation issue? Please help.

Cracked fuel lines on the top of the tanks and on the switching valve
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Old 06-25-2018, 02:21 PM   #4
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Re: Fuel starvation issue? Please help.

There also is a filter in the carb where the fuel line hooks up....That's where I found my problem once....it was a piece of Teflon tape floating around in that filter.....
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Old 06-25-2018, 02:24 PM   #5
75C10
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Re: Fuel starvation issue? Please help.

I had a truck once that would run but wouldn't drive. No power. Exhaust filled with mouse nests.
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Old 06-25-2018, 02:58 PM   #6
natedogg
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Re: Fuel starvation issue? Please help.

Thanks guys. I did put in a new fuel filter and that didn't help. Truck is a single tank and I'll check the lines on top of tank for cracks and check the exhaust for rats nest.
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Old 06-25-2018, 05:25 PM   #7
Pontiac1976
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Re: Fuel starvation issue? Please help.

Since you checked the carb fuel filter did you make sure the truck does not have another aftermarket fuel filter on between tank fuel pump, Or could be timing off a little. check to make sure the dist. hold down not loose. OH when you change a fuel pump did you make sure you got the air out of the line. Because a air bubble moving around ( fuel pump to the carb ) when motor warm it will cut the fuel down make you crazy like not getting a full fuel bowl for the dam you higher rpm.
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Old 06-25-2018, 05:42 PM   #8
natedogg
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Re: Fuel starvation issue? Please help.

There is no extra filter between pump and tank. When I put new pump on, I left line off the carb and cranked it over and watch gas shoot out. Distributor is tight and set correctly.
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Old 06-25-2018, 07:16 PM   #9
Jake Wade
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Re: Fuel starvation issue? Please help.

There is a fuel pickup screen/sock in the fuel tank, perhaps its clogged.

Is the timing advancing as it should?
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Old 06-25-2018, 07:53 PM   #10
truckin 79
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Re: Fuel starvation issue? Please help.

I would say it is electrical since you know you are getting gas. Check coil check control module
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Old 06-26-2018, 09:24 PM   #11
natedogg
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Re: Fuel starvation issue? Please help.

Turns out it was the control module. Swapped in a used one I had laying around and truck runs great now.
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Old 06-27-2018, 09:59 PM   #12
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Re: Fuel starvation issue? Please help.

Glad to hear you got it figured out!
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