1992 Facelift 5.3 Engine Wiring Harness Rebuild

My vote for looks goes to the braid as it’s the most modern. My vote for function and protection would definitely NOT go to braid because it provides exactly zero protection, I would even go so far as to drip a bit of fuel, see if it melts?

What I have done is use the non-sealed heat shrink and only shrink it with heat at the ends- that way it can still flex as the wires can still slide inside of it.
Harness tape would be best for areas not prone to abrasion; a lot of current vehicles use this with only 50% of the harness covered. Saves material and cost. I used it a little differently, overlapping each wrap about 25%. It has no adhesive so harness is flexible (especially the way the OEMs use it). Just super glue the wrap at the start and finish of the wrap and only glue it to itself. This allows easiest branch offs.
Never use vinyl electric tape; harness becomes rigid and a sticky mess with oil or heat, and then the adhesive fails.

The expandable braided sleeve is polyester, so at least somewhat resistant to gas. Flame retardant and good up to 125 degrees Celsius.

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As I said, braid looks the best. But also as I said not sure what protection all those holes in the braid offer? In the first picture of the braid and cable you posted up there the braid is see-through towards the ends. But if the cable you’re using has good enough material for isolation then the braid is just cosmetic in which case go with braid.

I’m working in the EFI portion now. There’sa but of discrepancy between the diagram and how the car was actually wired.

The diagram shows 1,2, & 3 (orange/blue on bank A) grouped together and 4, 5, & 6 (orange/white) grouped together.

How the car was wired was alternating injectors grouped together 1, 3, & 5 (OU) and 2, 4, & 6 (OW)

I’m guessing I should wire to how the car was wired not according to the diagram.


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I guess the alternating grouping matches what @V12JagGuy posted:


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There is a discrepancy on one year’s diagram. I don’t know why. It doesn’t really matter because the two channels for each bank are fused in the ECU so they actually fire in bank to bank batch as if the ECU only had one channel per bank.

~Paul K.

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Thank you, Paul, for the clarification. I see the section in the ROM and the Book that describes these groupings.

I was going off the 1992 MY Electrical Guide - looked up other years and, yes, seems like '92 there was a typo.




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No problem.

Take another look at the 90-91 diagram. It’s ok. The injectors are in order, but note the connections are staggered. I think it was only the 92’ year that had the strange diagram.

Actually you’re exp is the first time that I know if that confirms the diagram is wrong. All other factors indicated such (no change in harness part number, — surrounding years being shown wired the same - staggered)…

See how 2, 4, and 6 are on one connection, and 1, 3, and 5 are on another?

Again, if you got it wrong, it’d be ok since they’re fired bank to bank. I’m guessing that if a connection went out, the engine would still run a bit more balanced on that 9 cylinders than just on 6 on one side and 3 in the back or front of the other? IDK.


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Yep, '91 diagram has ordered injectors and alternating wiring. '92 diagram has ordered injectors and ordered wiring, '94 diagram has alternating injectors and ordered wiring.

I had already gotten quite a bit done on the B bank following the diagram before I noticed the discrepancy. Still debating if I should start over.

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Decided to scrap the previous start on the efi harness. Originally was going to run the B side to the front then along the fuel rail hose to the other side, but got looking into other routing options. This is the third, and final, layout.

Got some nice shielded wire yesterday. Hopefully get into the ignition coil/power module portion this weekend.

That sure looks nice and cleaned up the area - Tex.

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Where did you get the shielded wire?

I found some on ebay: https://www.ebay.com/str/empiredon

Went with 18 awg 2-conductor ($16.58/ 10 ft.) and 20 awg single conductor ($10.19/ 10 ft.)


I bought some coax cable from showmecables.com but it wasn’t quite right. But it was very cheap ($0.23/ft). Also got some 2-conductor shielded wire ($0.20/ft) from iec.net but the shielding was around the individual conductors, not around both. Plus the shielding was very fine gauged wire.

Why does everyone wanna move those wires up to the fuel rail? I think it looks terrible.

I didn’t verify, but I could have SWORN your book suggested this to get it away from the heat.

I had a feeling this was coming. I noted Kirby’s response in an earlier thread where he said just a little off the floor would be fine (level of the bolts holding the intake manifold), particularly if you’re using the appropriate temperature range wires.

It’s a very good idea to get those wires off the deck of the V, where they sit in the accumulating grease and muck. But right up top where they dominate the appearance of the engine? No need for that. I moved mine about an inch off the deck, to the level of the intake manifold flanges, where I secured them with clamps under the intake manifold nuts. They are off the deck and still not too obtrusive.

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And here I thought Jag made serious improvements with the “face-lift”, even the orphan 5.3 in MY '92. :confused:

Geez, JJ . how many miles does that cat have on her? :confused: