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Fuel Pump Wiring


NAXJA Forum User
I'm swapping a 4.0/aw4 from a 95xj into a 85 cj. I pulled the PDC and engine/trans ecu from the xj and wired in the ignition/crank/run from the CJ to the XJ. I was planning on using the fuel pump wire from the PDC but I'm not getting power.

Not ideal, but the project has been moving around in stages as I identify the parts I need. So I get partially though a project then have to stop and wait for parts.

When I first started the wiring I connected the ignition/crank/run wires from the CJ to the XJ PDC and all seem to test okay. Then I looked for the fuel pump wire from the XJ PDC relay. I think it is a green/white wire that goes to the bulkhead connector. When I tested this wire it powered on with the ignition in the run position then turned off. Great it looked like this was the prime so I thought I found the correct wire. Project stalled for a bit but I just finished the rest of the plumbing (fuel/trans/steering) so I thought I'd see if it would start. Nothing. I pulled a fuel line then tired again and no fuel. So I tested the wire and there is no power in the run or crank position. Then I hard wired the fuel pump to a spare battery and the truck started right up.

So my first question is am I tapping into the right wire? If so, what would prevent the relay to deliver power to that wire? I did swap the relay with another from the PDC but that didn't work.

The wiring is a mess, as you can imagine, but I don't want to start thinning it all out until I know everything is running properly.

Any ideas on what could be going on?
So I bypassed the relay 87 to 30 and the fuel pump kicked on and the truck fired up.

So whatever tells the relay to switch on isn't doing its job (also swapped in different relay so I assume the relay is good).

Any thoughts?
When does 86 get 12v? When in the run position? Will check the ground (i suspect this may be the issue since it was switching a few weeks ago).
86 has power when the ignition is in the run position. 85 shows continuity to the battery (-).

Are the grounds for the PDC the larger black/white wires that go to the engine block next to the coil?
Figured it out. When thinning the wiring for the swap I didn't splice the ecu +/- after I clipped them from the bulkhead connector. Wires spliced and it's running!

Just need to finish the brake wiring for the AW4 and figure out the shift linkage.

Thanks all. I'm sure I'll be back.