"fuel pump prime" wire - can someone confirm for me?

[PTAaron]

I am trying to rule out a fuel pump problem in another thread - but I was hoping someone can confirm for me that the wire I am using is the "Fuel pump prime" wire. We're looking at a '94 3.1L Cutlass Supreme, the diagram I found online shows WHERE it is, but now what it looks like.

This is the wire I found near the drivers side shock tower - it is has a connector at the end of it that is pretty corroded:

 

This is the diagram I mentioned that has the location marked with "N9":

 

Thanks for any help!

 

EDIT: I realized I linked the wrong diagram - they are labeled incorrectly on the autozone site... corrected diagram.

Edited April 19, 2014 by PTAaron

[PTAaron]

While we're at it what is N8 - "Oil Pressure Switch Fuel Pump"? Since I was removing things from that area of the engine - is that something that would kill fuel pressure? Hmm...

[RobertISaar]

that is the correct wire, that wire CAN supply power to the fuel pump anytime the fuel pump relay is off(if the relay is turned on, the current path the prime wire uses is broken).

 

oil pressure switch is used as another source of power for the fuel pump should the relay fail. above ~4PSI or so of oil pressure, the switch closes and gives another current path for the fuel pump.

[rich_e777]

The oil pressure switch is located just above the starter tucked in beneath the exhaust manifold a bit to the right of N8 in the diagram, do not confuse it with the knock sensor closer to the oil filter. I to have a loose connector similar to that hanging loose around the air temperature sensor in the intake tube never had it connected and forgot about looking it up until you mentioned it. You need a special socket to remove the oil pressure switch.

[PTAaron]

Thank you both!

 

Am I correct in my understanding that if I apply 12V to that wire and I get nothing from the pump, then either the pump or the wiring to the pump have failed?

Edited April 19, 2014 by PTAaron

[RobertISaar]

probably.

 

to remove everything else on the circuit, disconnect the PCM's A connector(clear/white) and the oil pressure switch, then the only thing that wire should be sending any current to is the pump.

[PTAaron]

Thanks, I will give that a go tomorrow before proceeding any further.

Wish there was a way to E-send you a case of beer for all of the helpful advice you've given out!

[Schurkey]

On my '92 and '93 Luminas, there are two wires connected to the "jump- start post"; a heavy cable and a much smaller wire. The smaller wire is the power supply to the fuel pump fuse which feeds the fuel pump relay, the first six or eight inches are grey fusible link, which splices to ordinary red-jacketed wire. The wire you pictured is the fuel pump relay bypass.

 

For what it's worth, on both my vehicles every place I tested for voltage drop showed excessive drop. Every bit of factory wiring for the fuel pump is under-sized.

Edited April 19, 2014 by Schurkey