I'm doing the wiring for an engine swap putting a 5.8 into a 84 bronco.
i have the complete engine harness and front compartment harness with the lights and all that came with the engine out of a 95 bronco it includes the main fuze block and the ECU . but what i dont have is the inside harness i just need know how to mate the two together.
can anyone help?

 

First off, welcome to FTE and the Big Bronco Forum. We will do our best to get you the most accurate info we can muster.

So, before I try to give a an answer, does the wiring that you have include the large multi-pin set of connectors that pass through the firewall? (The 95 that the engine came from would have this).

The interior side of the harness would include the connector for the ECM and branch circuits from the multi-pin connector to the gauges and "idiot lights". While not necessary, you would do well to track down a copy of the multi-pin connector diagram or "pin out" configuration. The Haynes service manual for these trucks is pretty accurate for wiring information and would probably be a good investment. With the information as to which wires are for which device, you can more accurately determine what goes where. The critical circuits are going to be ALL of those that must run to the ECM. So, you are dealing with a MINIMUM of 60 wires to the ECM. To run the engine, as long as the sensors on the engine and the power feeds and grounds are all connected, you should be good to go. If you don't have the interior side of the harness, I would recommend finding one. Running 60 individual wires is going to be a small nightmare.

 

I do have the harness that goes thru the fire wall and connects to the ecu. It also has the mult pin side for the inside harness and that is the one I dont have.(the inside harness to the gauge cluster and ignition switch) this guy that I am wiring up the truck for does not care if any idiot lights or gauges work he just needs the motor running right now and will add after market gauges and lights at a later time. This bronco will never see the road again it is for an off road toy only so the simpler the wiring the better, like no anti lock, no A/C, ETC...
So basically what I'm looking for is the wiring to energize the ECU and coils, injectors,and the rest of the engine stuff,thru the multi pin fire wall connection to the existing wiring inside the bronco.
I am not afraid of hacking into the multi pin to make this work i just dont to want completely destroy it for future use,as i will probably be the one adding the headlights and other stuff down the road

 

Then definitely invest in or borrow a copy of the Haynes service manual for the '92+ era F-series and Bronco. Not only does it show the wiring details but it lists very accurate wire colors which makes tracing specific circuits a much simpler task. You should be able to determine which portions of the wiring need to run back to the ECM and even what the other wires were originally used for in the '95. If you need a "pin out" for the 5.8L ECM, I can get that to you.

 

If you could get me that pin out that would be great.
I bought the chilton manuals for both the 86 bronco and the 95 broncos they are about useless for what i need. just let me know how to get in touch or where to send my e-mail and i will do it.
thanks.