Fuel Pumps
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Junior User
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Fuel Pumps
I've got a '93 V8 5L with dual tanks and I just started to notice a whine. Does dual tanks mean dual fuel pumps? When I switch it to the front tank, there is a whine beneath me and when i switch it to the back, the whine is gone. Any help that anyone could provide would be great. Thanks. 93cc.
Post Fiend
Joined: Oct 2003
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From: New Jersey
Originally Posted by 93candycane
I've got a '93 V8 5L with dual tanks and I just started to notice a whine. Does dual tanks mean dual fuel pumps? When I switch it to the front tank, there is a whine beneath me and when i switch it to the back, the whine is gone. Any help that anyone could provide would be great. Thanks. 93cc.
The front tank is kinda underneath you, doesn't necessarily mean its going, but your sitting much closer to it than the back tank which is at the tail end of the truck.
Switch tanks, leave it in park, and listen from the side and back of the truck you'll find that both pumps make at least a minimal amount of noise. If it's really loud, it might indicate its going (worn bearings)
Elder User
Joined: Sep 2004
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A 1993 truck has two independent high pressure fuel pumps, one in each tank. It also has a double-pole, double-throw electrical selector switch in the dash that routes power to the appropriate pump and connects the fuel guage to the appropriate sender.
A 1993 truck does not have a multi-port valve. That was the 1989 and prior design.
Start the truck, let it idle in park. Set the switch to the front tank. Step outside the cab and listen. You should hear a whine. Flip the switch to the rear tank. Walk to the back of the truck and listen. You should hear a similar whine.
It may be difficult to discern the sound of the pump over the noise of the engine and exhaust. For extra credit, you can ground the FP wire in the diagnostic connector; with the engine off. Pulling FP to ground will engage the fuel pump relay and force the selected fuel pump to run. Now you will have peace and quiet to compare the sound of the two pumps against each other.
A 1993 truck does not have a multi-port valve. That was the 1989 and prior design.
Start the truck, let it idle in park. Set the switch to the front tank. Step outside the cab and listen. You should hear a whine. Flip the switch to the rear tank. Walk to the back of the truck and listen. You should hear a similar whine.
It may be difficult to discern the sound of the pump over the noise of the engine and exhaust. For extra credit, you can ground the FP wire in the diagnostic connector; with the engine off. Pulling FP to ground will engage the fuel pump relay and force the selected fuel pump to run. Now you will have peace and quiet to compare the sound of the two pumps against each other.
