So I got the 2.5 litre engine in my 1994 Ranger from my 1999 Mazda donor truck. It went very well. Now I need help hooking up the engine wiring as none of the connectors match. I have headlights and the like which means I didn't screw up the original wiring. I dont have the computer hooked up because I need to extend the wires to locate is in a safe spot where old computer was, and I am afraid I will smoke it. any Idea how to do this given my inexperience? All the wiring diagrams i have are just for minor body and chassis and I can't figure out how to decipher the information i need for changes. Thanks in advance! I can supply pictures if you tell me what to send.

 

You will have quite a few issues on the way

1994 was a 60-wire OBD1 computer system, running 30psi fuel pressure
1999 was a 104-wire OBD2 computer system, running 60psi fuel pressure

Ford sends out "Shop Manual Sets" every year for every model they make to ALL the dealer shops
Usually 3 or 4 books in each Set
The wiring diagrams are in a separate book called the EVTM until 1998, then "Wiring Diagrams" 1999 and up, these are often sold separately

You will want to get a 1994 Ranger EVTM, like this one: https://www.ebay.com/itm/234701205758

And a 1999 Wiring Diagrams book like this one: https://www.ebay.com/itm/374235535631

And these are basically FREE, you buy them, use them then re-sell them just like the people you will be buying them from did
Its just information, nothing is "used up" as long as they stay usable they will have value for re-selling

DO NOT rely on Haynes or other general Ranger wiring books, only use the Ford Books

There is not a lot of crossover wiring between Vehicle systems and Engine system, which is good, but you need to separate these wires from the "main" harnesses
Which is timing consuming
Engine system just needs 12v and ground to work, its a self contained system
Get the Books, you WILL need them

 

I received my books recommended by RonD. I left dash wiring harness in the 1994 Ranger and I have dash lights, turn signal, headlights ETC. I am at a loss where to start. I have my 1999 engine and PCM installed. The 1999 power, to the power distribution box went directly to the front of the PDB. The 1994 is hidden in harness? At this time I have no power to the engine. There is a connector on the 1999 engine, C124. I believe I need to find where each wire goes and match it up to the 1994 wires. Do these all go into the PDB? Do I need to use the 1999 PDB instead of the 1994? Soor if this is a confused as I am. Is there a general list of circuit numbers? My book says for instance pin number 1 is circuit 16 (red/light green) but I find no list.

 

Without having the same Wiring Manuals we can't be much help

But there are 4 types of wires
12volt full time
12volt Key On
Ground to battery negative, full time ground
Ground to control a device

The engine devices and Computer(PCM) get 12v Key On power from PCM/EEC relay in both years, well all years, lol

 

I received the exact ones you recommended. the 1994 Electrical and vacuum troubleshooting manual, and same in 1999. Are saying you dont have these available to you? any suggestions where I start?

 

Let me see if this works
I understand that I need to remove anything that is not engine related from the 1999 harness. If i unwrap harness, anything from engine connector c124 that goes to PDB is a keeper and all the rest can be eliminated? is this too simplified? I dont need any windshield wipers, headlight, or turn signal wires because they exist from old harness

 

No, why would I have those?

While I do have a 1994 Ranger I have never needed its EVTM, so far, lol, and never owned a 1999 Ranger

I would start at the Grounds for the Computer, usually 4 or 5 of these
Next would be the 12v Key on power usually just 1 wire, RED in most years

Then 12v full time, for computer memory, Yellow wire, in both years

CEL(check engine light) wire is important, wire #2 on the computer, pink/green in both years


The engine wiring harness doesn't need to be changed, plug and play
IAC Valve, EGR and EVAP solenoids may need to be spliced to RED Key on computer wire BUT..............that should already be done in the main harness, you just need to find that one RED wire that is powered from EEC/PCM relay

As said this swap is not an easy one, going from 60 wire computer to 104 wire computer requires some work
You need to see what each wire from the 1994 Engine fuse box does, and then see what each wire from the 1999 engine fuse box does, as far as engine systems
There will be no cross reference, YOU are the cross reference

 

You say engine is just plug and play, I understand that if the plugs matched... Im in over my head here time for the junkyard i guess.

 

Yes, 1999 engine, 1999 computer and its wiring harness are plug and play, just add 12volts and grounds