fuel pump woes
04-09-2009, 08:25 PM
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Year: 1987
Model: Cherokee
Engine: 4.0 soon to be gc ho 4.0
fuel pump woes
just instslled new fuel pump on my 87 xj...no start though just turns over...i can hear pump kick on so i know it works...is there anything i need to do like priming the fuel system to get air out or what ....im gonna change the fuel filter tommorow even though its new maybe junk from the old one during install fell of or something blocking flow?
04-09-2009, 08:38 PM
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Year: 1987
Model: Cherokee
Engine: 4.0 soon to be gc ho 4.0
well how do i do that? and yea its getting spark i stuck my finger in a plug wire. (it feels good) lol was running fine before i replaced the pump now it just turns over no sputtering or spittin'
04-09-2009, 09:12 PM
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Year: 1987
Model: Cherokee
Engine: 4.0 liter RENIX I-6, DIY Cold Air Intake, 2.5 FM Exhaust, 3 Core Radiator
The pump is bad. Pull it out and return it and get another one. I had the same problem when I changed the fuel pump in my 91 XJ. The first new pump made noise all day when you turned the key on but no start just crank....and it was getting no gas. I pulled the line off at the fuel rail and verified it. I got a second pump and it worked as advertised.
There is also a chance that you reversed the wires when you hooked them up to the new pump and it's turn in the wrong direction. In effect it would be trying to pump gas out of the fuel line and into the gas tank.
There is also a chance that you reversed the wires when you hooked them up to the new pump and it's turn in the wrong direction. In effect it would be trying to pump gas out of the fuel line and into the gas tank.
04-09-2009, 09:17 PM
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hmmm...yeah that is weird....i had a similar probllem...and someone told me to change the crank sensor...I changed it out and no problems since...All of your fuses and relays are good? I pretty shure there is an engine shutdown relay that ocasionaly goes bad...Which will the allow the engine to turn over but not fire.
04-09-2009, 09:44 PM
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Year: 1987
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forgot to mention that too...i replaced all the relays today as well... im gonna get a fuel filter and crank sensor tommorow'
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04-09-2009, 09:50 PM
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Year: 1987
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Engine: 4.0 liter RENIX I-6, DIY Cold Air Intake, 2.5 FM Exhaust, 3 Core Radiator
Disconnect the fuel line at the fuel rail and turn your key on and see if gas shoots out. While this sounds like a pretty extreme test. It might just save you some time and money on buying a bunch of relays and a CPS that you don't need!! It only takes a couple minutes to try. I guarantee you that either that new fuel pump you got is bad or you hooked it up backwards. You did say it only had a bad fuel pump when you started working on it, right?
04-09-2009, 10:00 PM
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Year: 1987
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before i started on it it ran fine just little choppy but ran. after i changed the pump tried cranking it and it would smoke the wires and by the selenoid and would get hot....so i felt the wires goin to the fuel pump and they were as well too it wasnt making anynoise. so i pulled the pump back out and switched the wires even though the short wire going to pump went from bracket to pump looked like my ground it must not have been because when i switched the wires and re-installed it started humming like you would expect to hear. cuts on for a sec when you turn on then stops just like always only when turning it over it never starts. ill go check if theres fuel coming outa the rail.
04-09-2009, 10:06 PM
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Year: 1987
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Engine: 4.0 soon to be gc ho 4.0
ok turned in over with the line goin in fuel rail disco'ed and pulled out some..turned over and no fuel came out.....can a fuel pump run backwards? when it was hooked up the other way it caused the wires by the starter selenoid to get hot and smoke...im going to change the filter tommorow and check the screen as well could that keep it from getting any fuel at all to rail?
04-10-2009, 09:32 AM
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Fuel pump resistor
On the left fender near the front is a white ballast resistor that sometimes breaks. I had a 1988 that did the same thing and I found this part broken and after I changed it all worked well. Oem part # is 33000682. You can go to my website at mopardiscountparts.com and plug that part# in to look at it.( it is white ceramic looking piece with 2 wires going to it.
04-10-2009, 09:38 AM
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Year: 1991
Model: Cherokee
Engine: 4.0 I6
On the left fender near the front is a white ballast resistor that sometimes breaks. I had a 1988 that did the same thing and I found this part broken and after I changed it all worked well. Oem part # is 33000682. You can go to my website at mopardiscountparts.com and plug that part# in to look at it.( it is white ceramic looking piece with 2 wires going to it.
04-10-2009, 09:49 AM
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It's old knowledge for those who had/have a ballast resistor that to test them you simply take a wire and jump from the plug on one side to the plug on the other side. If vehicle starts replace the part. You should not drive with the jumper in place. They are usually about 1" x 4" with a mounting bolt in the center.