'89 K1500 Crank no Start

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Schurkey

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1. Your fuel is so contaminated that it'd take gallons of "Iso Heet" to make it burnable again. Two bottles is a total waste.

2. Remove the fuel filter. Connect a hose to the tube that leads to the inlet side of the fuel filter (from tank to filter.) You can jump the relay to run the pump, (440 Orange to 920 Pink/Black when the fuel pump relay is removed, or 440 Orange to 450 Black/White battery + to 490 Red at the ALDL connector with the relay installed.)

Draining the fuel tank on my Lumina:
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3. If you disconnect the wire harness near the tank and check voltage, you'll be misled. The pump has to be RUNNING to properly verify supply voltage. I have a home-made jumper harness that I use. It plugs into the rearmost connector of the fuel tank wire harness before it goes up and over the tank. There's a bare spot in the insulation that I can use to check voltage without disturbing the vehicle harness; and there's extra length that makes it easy to connect an in-line or a clamp-on ammeter to measure fuel pump amperage draw.
 
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Scooterwrench

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If that is the correct schematic for your truck then it looks like you will jump 440(orange) and 920(pink/black). Check to make sure the wire colors on your truck are the same as in that schematic. Do not jump anything to black and white!!!
 

Schurkey

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Do not jump anything to black and white!!!
YES! I screwed-up on my previous post--which I've since corrected.

You can jump the power supply (440 Orange) to 920 Pink/Black with the relay removed, or supply battery + power direct from the battery or other source to 490 Red with the relay in place. 490 Red should be in the ALDL connector, and is the GM-supplied "bypass" for all the fuel pump control circuitry.

Note that some schematics show 490 as "Red" (for example, 1988 C/K Electrical Diagnosis Service Manual Suppliment, page 20-4) while others show it as "Red/White".
 
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