# Jeep YJ fuel problem



## havasu (Feb 27, 2016)

Son took my 90' YJ out for a spin, it died, and towed it to his house. He said it seems like the fuel pump died, since he no longer hears it whirling before start up. The jeep has a Hesco fuel injection system and the electric fuel pump is on the frame rail. He tried jumping the pump but it only sparks and doesn't turn on. 

All points lead to the fuel pump being bad but now the pump has no power to it when it is tested with a voltmeter. Stranger thing is now he discovered a green wire under the dash, that has been stripped 1/2 inch and has an exposed wire. This green wire is only key activated 12v, and this could be the primary problem. 

What I'm hoping is if someone can find the wiring schematic to tell me what this solid green wire had originally gone to. If it is not part of the original wiring, it must belong to the wire loom for the F/I system. 

Paging Mustang!


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## mustanggarage (Feb 28, 2016)

I do not have the wiring schematic.  but why don't you just take a piece of wire, vice grip it to the battery cable, run it back to the fuel pump and see if it will run.  I would use my power probe tool for this, but a simple jumper wire will tell you if the pump is bad.  if it is not then you can trace the wiring back.  with my jeep, there is a whole mess of wiring that is just not hooked up anymore, bypassed or just tied up under the dash.  I really need to go in and strip it all out and re do it.  maybe some day.


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## mustanggarage (Feb 28, 2016)

what I mean is basically bypass everything hook the wire to the fuel pump first, then run it up to the battery.  touch it to the battery, or use the vice grip to hold it on.  if the fuel pump goes then you know it is good.  then you start tracing wires and checking fuses and relays.


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## havasu (Feb 28, 2016)

Thanks for responding. Yeah, he first attempted to jump the pump and just got a spark at the pump terminal. I told him by doing this, it sounded like the pump was shot. But he then said when trying to turn it over, he saw there was no power going to the pump. I think the fried pump either shorted out the relay (causing the spark). Yeah, a typical jeep has lots of unused wiring. Add a Hesco F/I system, and your unused wire is now double. 

His plan is to first replace the pump, then do a wire trace on bare wire.


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## mustanggarage (Feb 28, 2016)

ok.  I understand.  multiple problems.  well I do not have the original schematic but I do have the hesco installation instructions.  the fuel pump wire if I remember correctly is green with black stripe.  the site will only allow me to upload 700 mb pdf file, You can download them here, however.


http://www.hesco.us/products/7541/e...-automatic-transmission-p5249686#.VtO3l9BSJeg


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## havasu (Feb 29, 2016)

Yeah, I'm really looking for the Hesco wiring schematic, but can't find it as well. Maybe I will send Leee a message to see if it is located on his website somewhere, because I can't find it. I think I will be taking a drive over to my son's house to start tracing the bare wire. 

Thanks for the help MG!


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## mustanggarage (Feb 29, 2016)

just go to that link I posted, you can download the pdf from their website.

just scroll to the bottom of the page and there is a section called downloadable files.  their is a tips file and the full installation instructions.

there isn't a schematic but there is instructions that tell you how to wire it and from what I read it says there is a green with black stripe wire that should be to the fuel pump. BTW you should also check the relay.


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## havasu (Feb 29, 2016)

Oh, I gotcha. Thanks for this.


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## Chris (Feb 29, 2016)

My jeep has very few original wires, can't help you on this one.


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## mustanggarage (Mar 3, 2016)

chris your jeep has very few original anythings lol.


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## Chris (Mar 3, 2016)

The seats are original. Well most of them.


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