Electrical Rjm 5.0 Harness

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
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Waldorf, MD
Which kit should i get the universal kit or the classic ford harness? Also does anyone know the difference between the two and why one is more expensive. Also any other special sensors or anything i may need? I have everything on the checklist pretty much just wonder if anything else is needed?

Thanks all
 
We used the universal kit to wire up EFI on my son's old carb'd Fox body.

I forgot exactly what the 'classic' kit contained that wasn't in the universal kit, but it is more expensive and contains more parts.
I think it had to do with upgrading the alternator, or extra harness to mate the new stuff with the old alternator setup... I could be mistaken...

Anyway, the universal kit was great.
It doesn't have any hook ups for emissions, it does away with the 'salt and pepper' connectors, has the EGR eliminator resistor built in, and you have to get optional 'extras' if you want alternator or A/C additions to the harness. Otherwise you build the RJM harness around the existing alternator and A/C harness.

You need ALL the sensors.
The kit is wires (which are labeled perfectly btw), fuse block/fuses, and relays.
The electrical tape they give, or at least what was in our kit, was useless. The looms and ties are nice.

The sensors you need are only the ones REQUIRED to run the engine. Anything to do with emissions is not required.

The O2 wires are very long. No extensions should be needed for long tube headers.
The fuel pump wires are long enough to make the fuel tank on a stretch limo.
The fuel pump impact cutoff will have to be mounted in the front kick panels if I recall correctly.
We mounted ours there anyway, and I a pretty sure we didn't shorten the lead, or we would have put it in the trunk.

The harness works on both auto and manual trans. There is one wire that you hook one way for one, and one way for the other. We were AOD when we installed the harness, and then went to T5, and just swapped the wire when we did the tranny swap.

There is a universal tach wire.

Then there is an optional wire for a CEL if I recall, but we didn't use it. Just deadheaded it under the dash.

That's most of what I remember about our experience.
I hope this helps some.

I also remember some of the wires being so long that I had to double them up inside the loom to hide the excess.
I didn't cut them to shorten them because the plug ends were installed, and I didn't want to have to re-install all the ends.
 
Here is a pic of the engine bay right after we got the EFI on the road.
It's quite a bit different today, but the harness is clearly visible.

The big loom along the firewall is the bulk of the harness.
It is so big because there is some of it folded over on itself to lessen excess wire length.
That, and it has some of the original chassis wiring incorporated into it so there was only one harness. (headlights, alternator, and such)

The only wire that I remember wishing was a bit longer was the IAC wire from the injector harness. I wanted to run it a bit differently than normal for whatever reason I don't recall. It is stock length... maybe 5" or 6" long.

This is an HO EFI in an 81 Fox Fairmont...
RJM.webp
 
Oh, and the wires go into the cabin behind the passenger strut tower.
You can see the fresh new grommet. They run to the PCM, which we put under a 4-eye Fox Mustang center console between the seats.
 
Here is a pic of the engine bay right after we got the EFI on the road.
It's quite a bit different today, but the harness is clearly visible.

The big loom along the firewall is the bulk of the harness.
It is so big because there is some of it folded over on itself to lessen excess wire length.
That, and it has some of the original chassis wiring incorporated into it so there was only one harness. (headlights, alternator, and such)

The only wire that I remember wishing was a bit longer was the IAC wire from the injector harness. I wanted to run it a bit differently than normal for whatever reason I don't recall. It is stock length... maybe 5" or 6" long.

This is an HO EFI in an 81 Fox Fairmont...
RJM.webp
Nice!
 
Yes this helps tremendously the only thing is i am not utilizing the passenger side grommet hole because of my tuck im going through a new hole in the door jamb and proceeding through my fenders so since this is long enough i have no worries now
 
Can anybody tell me which sensors i need to buy extra for this kit? Heres a list of things ive already ordered:

IAC
ECT
ACT
Speed sensor
Oil sending unit
TPS

I know i still need o2 sensors but am i missing anything else?