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I have a 1984 GMC Sierra heavy half ton 5.7 L V8 I replace the mechanical fuel pump and replace the coil pack yesterday I took the fuel line off from the carburetor and tried to start the truck and no fuel come out it has dual 25 gallon tanks where do I start and how do I know what is wrong

 

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I would check all rubber lines on fuel feed,one hair line crack and you are sucking air

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Did you install the FP correctly? You need to make sure you get the pump arm under the push rod that runs off the cam

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Fuel filter clogged?  

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All good ideas above, the only other thing I can think of is to ask the OP is to use the dash switch to go back and forth between the saddle tanks ( btw, I believe they're 20 gal) and make sure the fuel gauge moves. There is a solenoid that controls a valve that determines which saddle tank is being drawn from. Unlikely, but I suppose it's possible that the valve could get stuck in such a position where it isn't drawing gas from either tank.

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Yes I have checked my tanks they are on 3/4 and the other one is on a quarter tank and they do move I can't find a fuel filter anywhere I think whoever had the truck before me just bypassed it I've checked the wheel wells on top of the fuel tanks and close to the engine can't find nothing the fuel pump is hooked up correctly I had to hold it with a hacksaw to have the pushrod hit the metal to make sure it was working correctly. I have check all the fuses and they are lighting up fine with my tester but I can't find why the fuel is not pumping through

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The filter is in the carb inlet,1 1/16 wrench

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4 minutes ago, tnewman021 said:

Yes I have checked my tanks they are on 3/4 and the other one is on a quarter tank and they do move I can't find a fuel filter anywhere I think whoever had the truck before me just bypassed it I've checked the wheel wells on top of the fuel tanks and close to the engine can't find nothing the fuel pump is hooked up correctly I had to hold it with a hacksaw to have the pushrod hit the metal to make sure it was working correctly. I have check all the fuses and they are lighting up fine with my tester but I can't find why the fuel is not pumping through

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If you have the stock style quadrajet carb, there is a fuel filter in the base of the carb where the fuel line goes in, you'll need to use two wrenches to remove the line without twisting it, and I see River just beat me to it, ha.

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Yup,I too am waiting,not a tough system to solve,but the diverter valve,like you mentioned,seems a very good possibility

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If you have the stock style quadrajet carb, there is a fuel filter in the base of the carb where the fuel line goes in, you'll need to use two wrenches to remove the line without twisting it, and I see River just beat me to it, ha.
Yeah I pulled that one out as well and it's clean

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Here's a few pics also now my distributor is not wanting a fire56f3f977cd9d2f961dd3c3f0bcd088df.jpgacd2143532bc513a0a52bdec849ec813.jpg954487ac132db1333c61df804f94bddd.jpg

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Do you have a vacuum guage?put that on inlet of pump and crank motor over,if not, with inlet line removed from pump,add a extension to it,blow back thru it,have someone listen at fuel filler neck for gurgling,at the tank that is selected

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Well,power wire have 12v?,large wire,if yes,get a new ignition module

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Do you have a vacuum guage?put that on inlet of pump and crank motor over,if not, with inlet line removed from pump,add a extension to it,blow back thru it,have someone listen at fuel filler neck for gurgling,at the tank that is selected
No i dont

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Do you have a vacuum guage?put that on inlet of pump and crank motor over,if not, with inlet line removed from pump,add a extension to it,blow back thru it,have someone listen at fuel filler neck for gurgling,at the tank that is selected
Can I blow through it with my mouth or do I need a tool

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