inappropriate auto question

Hello everyone,I used to play with simple circuits when younger and hope to rekindle the fun at some point.Today I have an auto problem.I installed a new fuel pump and it wont stop running.I think I have isolated the switch and am wondering if anyone can tell from a schematic how to test it.This switch is directly tied to the oil pressure on this chevy and apparently it will shut down the fuel pump if the oil pressure drops to save the engine.Heres the schematic.**broken link removed**What Im thinking is,can I jump from the gray wire to one of the others to see if the pump stops.Question is,which one?It looks to me like if I connect it to the tan wire I will short it out and I dont want to spend another $100 on a pump.Any thoughts?All I remember from electronics class was the resistor rhyme:bad /boys/*aped /young girls/ but/ violet /gives /willingly.ha!IThanks everyone!

strongworx said:

I installed a new fuel pump and it wont stop running.

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I assume you mean that you replaced the exisiting fuel pump, rather than added an extra fuel pump.
So if the new pump is running all the time, presumably the old pump would have done the same, if you have not made any wiring changes.

strongworx said:

I think I have isolated the switch and am wondering if anyone can tell from a schematic how to test it.

Click to expand...

The problem is that your schematic is not very legible.

strongworx said:

What Im thinking is,can I jump from the gray wire to one of the others to see if the pump stops.Question is,which one?It looks to me like if I connect it to the tan wire I will short it out and I dont want to spend another $100 on a pump.Any thoughts?

Click to expand...

This sounds like a really bad idea, randomly jumpering from one terminal to another is unlikely to cause any damage to the pump, but may well set fire to the car wiring.

strongworx said:

All I remember from electronics class was the resistor rhyme:bad /boys/*aped /young girls/ but/ violet /gives /willingly.ha!IThanks everyone!

Click to expand...

Sorry but you missed out on Orange!
For those old enough to understand, try this:

"By Being Right On Your Grid Bias Volts, Good Working"

JimB

The most likely suggestion is that the fuel pump relay contacts are stuck. Switch the ignition on (don't try to start), wait 30 secs, remove the fuel pump relay.

The pump should stop.

If the pump stops, insert the relay again and listen for a "Click".

No "Click" but the pump runs = faulty relay contacts.

"Click" & pump runs = possible faulty PCM (Powertrain Control Module) or wiring from PCM shorted to ground.

FYI, the low oil pressure scenario should cut power to the pump and not allow it to run continuously.

HTH.

Judging by this low-quality drawing, there are redundant wires running to the fuel pump delay unit. You only need to add a fused wire from the ignition switch to relay coil, the NO contact to HOT feed, and the arm output to the pump. That's how my Dodge is wired.