Mallory Fuel pump Issues - electrical

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scrowe

scrowe

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The short story.......
I removed my fuel pump (mallory 4140) as I thought it was bad. Before ordering a new one I thought I would jump straight off the battery and found that it works fine. I have a separate switch to power the fuel pump but can't figure out the issue where the issue is at. Seems like it would be a fuse but have replaced several that were blown and still the FTP wont work. Must be electrical but where to look?

I am a logistician and not a technician so just give me some leads as to where to start or what additional information is required to narrow this down.

Thanks in advance.
 
Check power feed into the switch, out of switch and at the end where it attaches to the pump.

Check where your ground from the pump is terminated. It has to be a good ground on that wire.

Think of the circuit like a river, it's got to flow from one end to the finishing point
 
You mentioned switch. You don't use a relay? How large is the wire feeding the pump? You may have a bad connection, even inside the switch, or too-small wire and the pump won't start
 
Ground or hot. It's that simple.
 
You need to diagnose the circuit. Like was said - power flows from the positive side of the battery, through the wiring to the switch, to the pump, and back from the pump through the chassis to the battery negative side. A simple volt/ohm meter is best, but a 12V test light will also work for testing the sections of wiring. the fuse should be on the battery side of the switch - so between the wire that takes power from the car's fuse block to the switch. You might also want to look at wiring in a relay for it too. Wiring diagrams and diagnostic flow charts are easy to find online.
 
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