1982 C7000 7.0L Fuel Pump Diagram

Michael Owner/Technician Montreal, Quebec Posted   Latest  

Hi I have a 1982 GMC C7000 7.0L gas dumper at the shop. I have no power @ either one of my electric pumps in the tanks. Not sure exactly how its wired but I'm pretty sure it passes through my left or right fuel tank selector switch. I was wondering if anyone would have access to those wring diagrams all data doesn't even list that vehicle.

Thanks

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Stephen Owner/Technician
Port Perry, Ontario
Stephen Default
   

Changed my reply to not being familiar enough​.​too long ago

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Zachary Mobile Technician
Austin, Texas
Zachary Default
 

Identifix lists those vehicles vin their drop down but has zero information on them. I'd be happy to email them to check the archives but I have a feeling it's a dead end. That said, Faxon auto literature shows a gas wiring diagram for $19. Might want to call or e-mail first to be sure it includes all engines. All that said, I believe Stephen is right. Pretty sure that has a mechanical pump and…

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Michael Owner/Technician
Montreal, Quebec
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yea that's what I figured...

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Michael Owner/Technician
Montreal, Quebec
Michael Default
 

yea it has a mechanical pump and each tank has an electrical feeder pump and I have no power going to them if I supply direct battery power to either one it fires right up..... the fuel tank selector switch has 6 pins so what I'm thinking is it supplies voltage to either pump / as well as the gauges and ground is directly on the frame so its controlled power side only...

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Zachary Mobile Technician
Austin, Texas
Zachary Default
 

Ok gotcha. That makes sense. I remembered some of the pickups having pumps in the tank but I couldn't recall if that was only the throttle body injected versions or the carbureted one too. I imagine you are correct but it's tough to say without the diagram. I can shoot an email to Identifix and see if they have anything in their archives. Other than that, Faxon is the only place I know of that…

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Michael Owner/Technician
Montreal, Quebec
Michael Default
 

Perfect ill take a look and see if I can find any info thanks for the help guys!

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Gail Technician
Garner, North Carolina
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Poke around on the engine for an "extra" oil pressure switch with 3 wires. Back in the day they ran juice through an oil pressure switch as a safety feature. If the solenoid has 2 small terminals one is starter other is "resistor" which bypassed the resistance wire to the coil. Now that we use 5 pin relays you could wire pin 87a to provide power at key on, then when relay is applied pumps would…

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Michael Owner/Technician
Montreal, Quebec
Michael Default
 

Ok I'll check that out thanks !

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Gail Technician
Garner, North Carolina
Gail Default
   

As i mentioned before I would use the switch as relay ground so it keeps amp draw through it to a minimum.

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