View Full Version : RJM Injection Technologies Wiring Harness

September 19th, 2007, 02:04 PM
The wiring harness I had with my 88 Mustang 302 was pretty trashed. I had initially intended to reuse it and replace the little bits and pieces that needed it, but was turned on to this company: http://rjminjectiontech.com/

I ordered their EFI harness for "other" vehicles, which is slightly different than the Bronco or classic Mustang harness. It arrived promptly although they do require a signature from UPS for delivery. Fortunately, I was able to have a neighbor sign for it. Everything needed is included in the package.


It contains all of the loom, tape, zip ties, grommets, etc that you need. After installing the loom and tape, it looks like this.


All of the wires are labeled with their purpose, making identification for hook up very simple (sorry for the bad pic)


The harness installed pretty easily, although a couple of the wires, particularly the Air Charge Temp, Throttle Position, and Idle Air, were a little short. Installing the grommet in the firewall is big pain, but is really not too bad when you have the access that a buggy affords.

RJM claims that the harness is set to work with 89-93 engines and computers, and I had an 88. I decided to risk it and try using a supposedly non-compatible computer, but everything plugged in fine and runs correctly. I did have to splice in a piece of the OEM harness to fit my older MAF. No big deal.

The harness does not include any provisions for the smog controls (EGR, Air pump, etc) or air conditioning. The harness is made to supply the correct resistance in the smog control circuits to not light the check engine light. All of the expected codes given from the computer upon hookup are thoroughly explained in the instructions. I was lucky and only was given the expected codes for the non-functioning smog controls.

Overall, the harness did everything it claims to do, arrived promptly, and installed easily. I would certainly use this again in the future if another Ford engine finds its way into my garage.


October 17th, 2007, 08:35 AM
The guy is a friend and does great stuff with Ford fuel injection. He has a very informative free site http://www.fordfuelinjection.com He has what you need to swap from carb to EFI and high power alternators. I run his harness on my 90 Bronc. RJM = Ryan McCormick Never got his middle name.

He helped me wire and tune my Blown 349.

July 15th, 2009, 11:57 AM
Just a word of caution. RJM has a great website full of information and the product line is very extensive. However, if you need assistance from Ryan or sales@rjmtechnologies.com you may as well forget it. They do not answer e-mail, phone calls or mail in any form or fashion. The web site says they are moving but they have been moving since March. When it comes to technical assistance your on your own.