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no fuel power and noe fuel injectors pulse

Old May 26, 2012 | 01:19 PM
  #1  
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From: Covington Ha
Year: 1988
Model: Cherokee
Engine: 4.0
Default no fuel power and noe fuel injectors pulse

i have an 88 cherokee with the 4.0, auto, lifted 6.5 inches and 36 swampers

i have no power to fuel pump and the fuel injectors. i ran a hot wire to the pump to test to make sure it is not bad, it works fine with the hot wire. if i pour gas in the intake the jeep will start up and then die. i have replaced the cps. i checked the relay , the relay is good.


my jeep has been down for over a month i really need my jeep i have been borrowing a friends truck to get back and forth to work sorry if i am posting in the wrong section i am new to forums


please if anyone has any ideas please let me know
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Old May 26, 2012 | 01:25 PM
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From: Southern Oregon
Year: 1990
Model: Cherokee
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when i got my first cherokee it was an 88, it had a similar problem. turns out the rubber that holds it in place had been disintegrated from the gas and clogged up the pump. so i had to replace the pump and fillter and ran a can of seafoam in the tank to help clear out any remaining gunk. it was a good thing i got it for free lol
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Old May 27, 2012 | 11:27 AM
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I can get the pump to come on by running a hot wire to it. And it puts out good pressurei will check that when I get home tho. Did it cause your pump to stop working. And the injectores to lose power
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Old May 27, 2012 | 11:21 PM
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From: Southern Oregon
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I dont think the injectors lost power because all I had to do was replace the pump and filter and I was up and running again
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Old May 28, 2012 | 12:19 AM
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Year: 1989
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Engine: 4.0 L
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Perhaps it's your fuel pump relay. I don't know if there's a fuse for the fuel system. Check your fuses and relays though, that's definitely worth a shot.
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Old May 28, 2012 | 07:27 AM
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Year: 1990
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Originally Posted by joshga171
I can get the pump to come on by running a hot wire to it. And it puts out good pressurei will check that when I get home tho. Did it cause your pump to stop working. And the injectores to lose power
Are you measuring the pressure?

See if you've got power to your terminal 30 on the fuel pump relay and power to terminal to terminal 87 with the key on.

And yo udo know the fuel pump relay is the second one back from the front?
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Old May 29, 2012 | 01:06 PM
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I have power to the switch side but the prong 30 only has 2 volts
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Old May 29, 2012 | 02:46 PM
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Should have battery voltage to terminal 30.
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Old May 29, 2012 | 03:38 PM
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Does that power come staight from the battery or does it come from the computer cause the wire is orange not red
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Old May 29, 2012 | 04:24 PM
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From fuse link G, which would be on the start relay. It is orange at the start relay turning red at C103, a flat 6 prong connector near the passenger side shock tower.
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Old May 29, 2012 | 06:16 PM
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From: Covington Ha
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K so ifollowed the wire from the relay to the next junction. One wire goes to the start relay one to the 6 prong plug and 2 into the wiring harnes.

The 6 prong plug it goes In solid oragne nd cones out orange with a black strip

The 2 that go into the harnes go into the cab of the jeep neer the computer.
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Old May 29, 2012 | 08:57 PM
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The 2 orange. Ones that go in the wiring harnes. Go to the computer.

Where does the on that goes through the 6 prng plug go.

Another ? Does the power come from the first relay
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Old May 29, 2012 | 10:16 PM
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One goes to the fuel pump relay # 30. One goes to the ECU. One goes to the TCU. One goes to the diagnostic connector. I suggest you work from the # 30 connector back toward the start relay.
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Old May 29, 2012 | 10:36 PM
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I guess there are a number of fused links there off the starter relay, and that one, "G" powers the fuel pump, and more....?
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Old May 29, 2012 | 10:45 PM
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Originally Posted by DFlintstone
I guess there are a number of fused links there off the starter relay, and that one, "G" powers the fuel pump, and more....?
Yes. That's why the wire from #30 on the fuel pump relay needs to be traced back to it's source and checked along the way for voltage.
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