No signal from ECM to fuel pump relay

[Channeled 91]

hello everyone;
I am having an issue trying to start my truck. The fuelpump relay isnt turning on. It is a new relay. I checked the wiring. The orange wire has power, but when I turn the truck over, the dark green and white wire from the ECM is not registering any power. It ran before. I am hoping it is not the ECM. There is no fuelpump / oil pressure switch, for I am running after market gauges.

 

[PlayingWithTBI]

Are you sure you don't have the fuel pump oil pressure switch? It's a 2 wire switch (not a sensor) on the back of the engine near the distributor.

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[evilunclegrimace]

hello everyone;
I am having an issue trying to start my truck. The fuelpump relay isnt turning on. It is a new relay. I checked the wiring. The orange wire has power, but when I turn the truck over, the dark green and white wire from the ECM is not registering any power. It ran before. I am hoping it is not the ECM. There is no fuelpump / oil pressure switch, for I am running after market gauges.

The year, model and engine would help a bit.

 

[PlayingWithTBI]

It looks like the grey wire needs to get power through the switch and the in-line fuse...

 

[PlayingWithTBI]

The year, model and engine would help a bit.

Yeah, I'm just guessing it's a "Channeled 91", ha ha.

 

[Channeled 91]

The year, model and engine would help a bit.

1991 C1500 305 5.0L V8.

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[Channeled 91]

I believe the fuel pmp / oil pressure switch was removed and replaced with the Stewart Warner oil pressure sending unit.

My gauge arrangement.

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[evilunclegrimace]

Yeah, I'm just guessing it's a "Channeled 91", ha ha.

Good guess!

 

[evilunclegrimace]

reinstall the original OP switch with a Tee to run your new gauge and your problem will most likely be gone.

 

[Channeled 91]

reinstall the original OP switch with a Tee to run your new gauge and your problem will most likely be gone.

I donthave the OP switch. the gauges were swapped out before I bought the truck.

The dash that was init when I bought it.

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