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sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 22827
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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I have 1995 cherokee 4 liter engine installed in a 1983 CJ-7.

Customer Question

I have 1995 cherokee 4 liter engine installed in a 1983 CJ-7. I cobbled together an in-tank fuel pump from a chevy 2000 cavalier that worked fine for 4 years. I replaced this pump with a new pump designed for a typical 1996 chevy p/u or 1500 blazer with a 5.7 liter vortec and wired it in the same. Not only does the pump not work but I no longer get that 2 to 3 second prime signal I used to get when the ignition switch is intially turned on. There is no voltage available at the fuel pump hot lead.
Submitted: 2 years ago.
Category: Jeep
Expert:  sprinkles08 replied 2 years ago.
Hello and welcome to JustAnswer!
I'm assuming that you're using the Cherokee's engine controller and wiring. If the PCM controls the fuel pump relay as it originally would have and your pump is not running it could be a relay or wiring issue or the relay may be missing a power feed, but the PCM may also be down. The PCM may be down due to a loss of power or ground, a short to ground n a sensor reference voltage circuit, a short to voltage on the sensor ground circuit, or it could be an internal failure in the PCM.
Do you have spark?
Customer: replied 2 years ago.
There is no spark, it seems to be in "automatic shut down" mode. This problem intially started with the number 5 and 6 injectors not firing even though there was a node trigger, the engine ran but of course it ran poorly. I replaced all six injectors and they still weren't firing. I checked fuel pressure and there was little to no pressure. I installed a new pump and that's how I got here with the engine in shut down.
Expert:  sprinkles08 replied 2 years ago.
Do you have the engine light operable?
Do you have a scan tool with the correct connector?