4.3 TBI no fuel

YJJPWrangler

YJJPWrangler

Well-Known Member
Joined
Jul 19, 2005
Location
Charlotte
Went to Gulches this weekend with the Willys. Drove it 1/2 mile to camp, unloaded made it back to the truck and wouldn’t crank.

Found the battery ground was slightly loose, so tightened it down and it would crank again. However no fuel pump and it wouldn’t prime.

Hot wired the fuel pump to ensure the fuel pump works, which it did.

@ghost showed up Saturday and we probed some more. The fuel pump relay is not getting power from the ECM. I just swapped ECM with another one at the house and still nothing.

We have good spark, good battery, no fuel.
 
So what tells the computer to turn on the fuel pump? Since it ran it seems like something went out?
 
From the little reading I’ve done so far, it could either be the ignition control module or the oil pressure switch.

I know you can test the ICM but unsure how to test the oil pressure switch since it’s just a mechanical line that plugs directly into the oil pressure gauge
 
@R Q, my ECU power line(that's always hot) pulled out of the crimp but was still being held in place by heatshrink. So visually, it appeared that everything was working. I got home and started poking around and it easily pulled apart. Recrimped it, pump turned on and jeep fired right up and idled better for what ever reason.

Fuel pump is an intank pump for a 91 S10 that I grafted onto a TJ housing. It's grounded to the frame.
 
YJJPWrangler said:
@R Q, my ECU power line(that's always hot) pulled out of the crimp but was still being held in place by heatshrink. So visually, it appeared that everything was working. I got home and started poking around and it easily pulled apart. Recrimped it, pump turned on and jeep fired right up and idled better for what ever reason.

Fuel pump is an intank pump for a 91 S10 that I grafted onto a TJ housing. It's grounded to the frame.
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So, you found the issue and have resolved, correct?
 
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