4.2 to 4.0 head and MPI Swap ? - JeepForum.com
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post #1 of 2 Old 04-12-2010, 04:21 AM Thread Starter
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1987 YJ Wrangler 
Join Date: Apr 2010
Location: Everett Wa
Posts: 115
4.2 to 4.0 head and MPI Swap ?

So I'm 90 % complete with the swap and just have a few issues I'm running down. I have a 87 4.2 lower end with a 93 XJ head, MPI, harness, computer, PDC, flywheel CPS, alternator etc.

1. I have just installed a fuel tank with the correct internal pump. I used my stock harness and just put keyed power to the pump. Is this adequate, or do I have to run through the PDC and a fuel relay?

2. Also on the new xj harness there is a 10 GA? brown wire coming from the grey plug in the harness that is about 8 inches behind the alternator. Does anyone know where this goes?

3. Wiring.........I have all the sensors and sending units pluged in less the VSS and I need to find that and the speedo cable adapter at a bone yard.
Now I have the blue wire from the PDC hooked up to keyed ignition at my solenoid. The big ugly power from the PDC to my battery. What other wires to I have to tie in to my old harness to get going?

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post #2 of 2 Old 04-12-2010, 04:40 PM Thread Starter
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1987 YJ Wrangler 
Join Date: Apr 2010
Location: Everett Wa
Posts: 115
Need some help. Anyone?
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