The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1973-1991 Dual fuel tank systems theory of operation

**cdub2010** · 07-23-2023, 01:53 PM

My 1991 R3500 truck stopped running, no fuel to injectors, since I know the right side pump was dead, I dropped the drivers tank and found the ground was pinched and destroyed, the tank was leaking and sender was doused in tar. Best to replace and start new. I had found a broken switching valve so that was replaced as well. Connected everything it still wouldnt start.

Checked with a test light no voltage at the drivers pump connection. I have voltage at the nl2 connection, and I have traced voltage to the pass. side pump connection, but pass. side shows voltage in both right and left switched positions.

my wires on the dash switch are all white and 1 black, this truck has been a disaster when it comes to wiring, total clown show.

What to look for? ground problem? wire burnt or rubbed thru?

07-23-2023, 01:53 PM	#158
cdub2010 Senior Member Join Date: Apr 2014 Location: detroit mi Posts: 206	Re: 1973-1991 Dual fuel tank systems theory of operation My 1991 R3500 truck stopped running, no fuel to injectors, since I know the right side pump was dead, I dropped the drivers tank and found the ground was pinched and destroyed, the tank was leaking and sender was doused in tar. Best to replace and start new. I had found a broken switching valve so that was replaced as well. Connected everything it still wouldnt start. Checked with a test light no voltage at the drivers pump connection. I have voltage at the nl2 connection, and I have traced voltage to the pass. side pump connection, but pass. side shows voltage in both right and left switched positions. my wires on the dash switch are all white and 1 black, this truck has been a disaster when it comes to wiring, total clown show. What to look for? ground problem? wire burnt or rubbed thru?