So I'm doing the same kinda deal on my 92 5.0 5 speed f150 except swapping in an EFI 393. Does it matter what year truck the wiring harness comes out of as long as its a v8 right? Can i use an MAF 86-93 mustang engine harness cause i have a freind with an 87 mustang MAF harness? Also I have an A9L computer lined up on the computer end. Just need some clafification on the which harness i basically need. This truck is getting alot of projects going already!

 

You need a '92-93 harness IIRC. I tried to use a '92 harness in a '94 truck and the engine stuff worked with my A9L after I switched the EEC pins around, but the connector for the stuff in the cab was pinned differently.

I have a '92 5.0 under hood harness in the shop I'm not using.

 

if i used the 92 harness which additional harness would i need to get it to match up to connectors in the truck? Are the engine harness and underhood harness different harnesses altogether? Sorry for all the questions.

 

If you have a '92, the engine harness and engine bay harnesses are seperate, but together.. It's weird. The main engine harness connects to the engine bay harness right by the fuse box, the EEC connector and everything is incorporated into the engine bay harness. So if you have no harnesses, you need both, the engine and engine bay harnesses. The engine harness itself should be the same for all V8's I think. I'm using a '92 main engine harness with a '94 engine bay harness.. Here's a couple pics from when I did mine, just to give you an idea.

EDIT: I just read your post again.. You probably could use the stang harness, but I wouldn't bother. You can re-pin yours easier and add in a overlay harness for the extra injector wires, MAF wires, etc. I got my overlay harness from RJM Injection.

Under hood harness, minus engine harness





In this pic, you can see the main engine connector sitting on the fender beside the fuse box.



The plug on the right is the EEC. The other plug is the one that is pinned differently in the different years. That plug is where you get power for the interior.



In this pic, you can see the RJM Injection overlay harness for the extra wires needed to run the A9L. The harness is running over the brake booster and sitting on the fender waiting for me to install the wires into the EEC connector.

 

thanks man! So you're using a harness from the 92, one from the 94 plus the injection harness too?? Is this the harness you used ?RJM Injection Tech — Truck SD to MAF Harness

 

Yes, that's the harness I used from RJM. The portion of my harness that is physically on the engine, is from a '92. The main engine bay harness is from a '94. Don't think about that too much. Just make sure you use a main engine bay harness from the same year truck. So in your case, a '92 harness needs to be used.

 

So basically the RJM harness and my stock 92 harness is all i need then repin it to match! I follow now! thank you!

 

Got mine all up and running BUT now this thing is flooding out something fierce. Is the MAP sensor same as the BAR sensor connected in at pin 45? I'm trying to pin point which sensors could be causing the rich condition here. Timing seems to be on and the left bank o2 is brand new with the old o2 on the right side. Brand new TPS set at .96 volts and new iac valve. My main question is about the bar and map deal?

 

A MAP sensor without a manifold vacuum source functions as a BARO sensor. I assume you removed the vacuum supply to your existing MAP sensor?

 

yeah i have the line plugged to the MAP sensor. The truck was blowing some black smoke before I did my MAF/engine swap but now it really is blowing it out.

 

The BARO sensor should not be capped, it needs to be open to the atmosphere. If I misread your statement then I would suggest running the KOEO/CM checks to see if there are any codes. If that passes then you may need to start metering some of the sensor outputs.

 

ah I see. I was told to plug the line at the MAP sensor when converting over to MAF setup.

 

Just to be clear.. the vacuum line goin to the MAP should be plugged because you can't have a vacuum leak, but the vacuum port on the MAP sensor should be open to atmosphere.

 

So you now have the 393 in there with a Mustang computer? What injectors are you using and what is the fuel pressure. Also have you checked to see if the FPR is leaking out the vacuum port? If it does it's shot and needs to be replaced.

 

oh ok! I gotcha now!