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2003 liberty blowing fuse on fuel system
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Author:  j-rod [ Mon Dec 28, 2015 10:36 pm ]
Post subject:  2003 liberty blowing fuse on fuel system
I have a 2003 Jeep Liberty with the 3.7. It keeps blowing the fuse for the fuel rail. I have changed the asd relay, wiggled wires with it running and changed the pcm. Still blows fuses. So far 23 fuses since Christmas.Happens random and no pattern like rain,cold,dry,, etc. any help would be greatly appreciated!
Author:  Billwill [ Tue Dec 29, 2015 2:14 am ]
Post subject:  Re: 2003 liberty
j-rod wrote:
I have a 2003 Jeep Liberty with the 3.7. It keeps blowing the fuse for the fuel rail. I have changed the asd relay, wiggled wires with it running and changed the pcm. Still blows fuses. So far 23 fuses since Christmas.Happens random and no pattern like rain,cold,dry,, etc. any help would be greatly appreciated!


What fuse number is this and is it on the interior fuse panel or the box under the hood?

Probably a wire intermittantly chafing to chassis somewhere...usually impossible to find so you have to cut off the relevant wires at both ends and lay down complete new wires....not fun finding a problem like this! :?

Let me know the fuse number please and I will check out the wiring diagram!
Author:  j-rod [ Tue Dec 29, 2015 2:15 pm ]
Post subject:  Re: 2003 liberty blowing fuse on fuel system
Fuse 23 IIRC. For the fuel rail.

fuse panel under the hood.
Author:  Billwill [ Fri Jan 01, 2016 9:49 am ]
Post subject:  Re: 2003 liberty blowing fuse on fuel system
j-rod wrote:
Fuse 23 IIRC. For the fuel rail.

fuse panel under the hood.


Weird, my 2003 KJ Circuit Diagrams do not show a Fuse 23 inside the fuse box under the hood...could you check that fuse number for me please! :?
Author:  j-rod [ Fri Jan 01, 2016 8:54 pm ]
Post subject:  Re: 2003 liberty blowing fuse on fuel system
Billwill wrote:
j-rod wrote:
Fuse 23 IIRC. For the fuel rail.

fuse panel under the hood.


Weird, my 2003 KJ Circuit Diagrams do not show a Fuse 23 inside the fuse box under the hood...could you check that fuse number for me please! :?



#26. Sorry
Author:  Billwill [ Sun Jan 03, 2016 2:59 am ]
Post subject:  Re: 2003 liberty blowing fuse on fuel system
j-rod wrote:
Billwill wrote:
j-rod wrote:
Fuse 23 IIRC. For the fuel rail.

fuse panel under the hood.


Weird, my 2003 KJ Circuit Diagrams do not show a Fuse 23 inside the fuse box under the hood...could you check that fuse number for me please! :?



#26. Sorry


OK you need to download the 2003 Jeep KJ Service Manual here if you do not already have it...about 68 MB.

Go to the Wiring section and look at pages 8W-10-19, 8W-10-20 , 8W-30-2 and 8W-30-19 as well as the Connector/Splice section for connector C103 and Splice S178 locations.

You will see that the output of the ASD Relay feeds Fuse 26 with +12 volts which at the other end of the goes to connector C103 pin 1 via an Orange/Dark Green wire. This C103 connector is located near to the TCM next to C104 and C105.

The OR/DG wire leaves the C103 connector and goes into Splice S178 which is located above the transmission near the Oxygen Sensor 2/2 Downstream. This splice takes the +12 volts and feeds it to the PCM Connector C3 pin 12 to let the PCM know that the ASD Relay has energized. The splice also takes the +12 volts to each of the Fuel Injectors via OR/DG wires.

The ground side of each fuel injector receives a switched pulse of Ground from the PCM when that injector needs to fire.

Seeing as the blowing of the fuse is intermittant it is doubtful that a particular injector has a short in it...more likely one of the Orange/Dark Green wires is fraying to engine/chassis somewhere or fraying to one of the switched ground wires going to each injector as shown on 8W-30-19. Remote chance it may be the PCM has a fault!

So you would need to trace the wires going to each injector to check for any fraying of the wire insulation all the way from the PCM, through connector C110 to the injectors!
Also check the lead going from the Fuse 26 to the PCM connector C3 pin 12.

If you cannot see any physical damage it becomes very difficult to trace the problem...you would need to locate the Splice S178 and cut one of the OR/DG wires apart...measure with an Ohm meter where the other end of this cut wire goes and then cut that end off so the wire is floating. Then temporary replace this cut wire with a new section and see if the fault re-occurs. If the fault fault re-occurs, replace the removed wire...use solder and shrink tubing..and repeat the procedure.

http://www.colorado4wheel.com/manuals/Jeep/KJ
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