I have a 94 ranger, came with a 4.0 V6 when I bought it. I believe the engine was swapped into it and the engine was from a 93 since it doesn't have EGR. I could be wrong I'm kind of new to Rangers. When I got the Ranger the engine was blown and I was well aware of that, so I bought another used 4.0 complete engine. As I was cleaning the new engine I started noticing the EGR and the accesory brackets were a bit different. At this point the new engine looks brand new. I cleaned it all up, prepped it, and painted everything silver and black with 2000 degree paint. I decided to use the wiring harness that came with the truck as it looked to be in better shape. Problem is the old harness doesn't have the EGR connection or one big connector that hooks up to the engine bay (near the fusebox). On the new harness there are 3 of those big connectors. Also the new engine has what looks like a small module with a connector on the rear of the engine, and the old one has a blocking plate there. I think it's for timing, I'm not really sure. My main question is, should I cut open the new harness and figure out what I need and transfer it? Or should I just clean up the old harness and transfer whatever is broken? I'll post up some pics tonight to kind of clarify my questions. Oh I also forgot to ask, what is the difference between the red and blue top injectors?

 

if the new harness has 3 square plugs, (black, tan, and grey) then that is for a 95+ truck (obd II) and won't match the wiring in your 94 (old style dash, obd I). which means the motor is probably 95+, and the sensors won't match your old wiring. but, the long block should be able to be used, you just need to swap all the old sensors over to the new engine.

 

The first picture shows the Plugs from a front view

The second picture shows the new harness on top showing the 3 plugs and the 2 plugs beneath from the old one.

old engine

new engine

 

not sure what those plugs go to. the main engine to interior connection at the firewall for a 94 and older is a round plug. the 95+ has three square plugs.

but the last two pics you posted are of the cam position sensor. the second pic that has it is the old style, 94 and older. but, there are some 95s that got it. my 95 has the old cps like the one you posted.