painless wiring and factory wiring

[hazardiz]

Hey, I bought the stand alone painless harness for the 5.0 mustang motor and was just wondering whether the wires under the hood where my 4.0L used to plug in need to be pulled out with the computer and everything? or if i can just leave them hangin there? or is the 4.0 not being there and plugged in going to make things mess up for lighting or anything else? thanks

 

[410Fortune]

You did what now?

What 5.0L are you planning to run?
If it is a fuel injected Mustang 5.0L then you will need the fuel injected Mustang PCM and harness, along with the painless engine harness.

Can you give me details as to which painless harness you have (Whether its just the fuel injection/engine harness, or an entire EFI harness with computer)

Why did you buy this part? You should be using stock parts from the donor car.


Everything 4.0L must come out, it is likely you will use the power distribution from the 4.0L however.

Sounds like you are in over your head!!! hahahaha been there, done that...

 

[hazardiz]

good to know...lol... :thumbdwn: ...as for donor car...doesn't exist...bought the motor with just the injection harness on it for 100 bucks...so i had nothing but a complete 5L ready for a rebuild...thats it...so now i got it all rebuilt and want to get it all put in and since i have none of the 5L wiring i figured go painless so that the engine is stand alone incase i ever need to swap the engine into another vehicle if i wreck this one...so i bought the stand alone complete engine wiring harness...pretty much the new perfect system without a computer...and i got a computer from a friend...so all i was wanting to do was put the motor in and run it with the painless harness and get rid of whatever other old motor wiring from the 4L that i could...but i don't know which is motor wiring and if it ties into headlight or heater etc wiring...thats my problem...haha...i'm not too sure what i'm doin here eiter...but in theory it should work...i hope...hope that helps ya for explainin my situation...

 

[410Fortune]

the 4.0L harness is a combination of ALL OF THOSE THINGS.

They wrapped the engine harness up right along with the ABS, Power distribution, headlights. hahahaha Yup trust me on this, I know ALL about it.
You will have to remove the entire harness, and start cutting it apart.
Remove everything you want to ditch or keep, this is the ONLY way to integrate a new engine/drivetrain/pcm into the OHV 4.0L equipped trucks and keep all your factory systems in place.

Why did they do this? UI dont know, all ranger based trucks are this way, except for the 5.0L Explorer....
Most Ford's use a stand alone engine PCM and harness, but not these ones, its all integrated.

Now you still didnt list the specs on the 5.0L you got, what trans you plan to use with it, what computer you have, etc.

 

[hazardiz]

yeah...i wonder if i can just cut the wired that plugged into the motor hanging out of the harness? that would be the easiest...or simply tear it all apart...we'll see when i start getting it in...the 5.0 i built is a stroker to a 332...just the factory cam cause i don't wanna go too crazy...went with 70mm throttle body and mass air...had heads ported and 202 valves put in...i'm using a stock mustang computer from a 91 HO GT mustang...and there is a guy here at the dealership that can program computers and tune stuff...for a tranny i'm gonna run a c6 built up...and a BW1356 or dana 20 behind it...not sure which yet...

 

[410Fortune]

You will need to make a map of the wiring you have left and the wiring you want to install, then it will be clear what goes where and why.

Ihave more time in the wiring on my conversion then the actual work.

 

[hazardiz]

well my buddy owns a shop so he printed me out the schematics for the mustang and the explorer for all the harnesses...hopefully those will help...wonder if i will have a bunch of funny lights come on without a 4L in the front? cause i can't take the computer out can i? cause as you said its all tied into it...?

 

[410Fortune]

You will take the 4.0L computer out.

What I meant was ford wrapped all the harness together on these trucks. the power distribution stuff is a part of your PCM harness.

Basically you will take the 4.0L computer out along with most of the wires from it. This will mean cutting the entire harness apart to do this. In order to fit under your hood they put all the systems into one harness. You want to remove the stuff that controls the engine, then wire the new 5.0L engine controls and computer back in.

Make sense?
The new 5.0L computer willget hooked up to the dashpot lights, cruise control,. fuel pump, etc. The power wires for the alternator/charging system/headlights etc stay with the truck.

fun fun.

The complete books for both vehicles is a MUST, I have a library.

 

[hazardiz]

hmm...sounds like i've volunteered myself for a job that sucks...lol...oh well...truck doesn't hafta be on the road till next spring...

 

[410Fortune]

Dont be afraid of it,. it can look overwhelming but once you start into it it will begin to make sense.

As LONG as you have the complete wiring books for both trucks.
The 4.0L OHV is the odd ball, almost all other Fords use a pretty much stand alone engine harness, but NOOOOOO not the OHV 4.0L.....hahaha

 

[hazardiz]

i think i'll just leave all the plugs and stuff just hangin there and computer in the truck and put the painless one ontop of it with the new computer tucked somewhere from harms way...but we'll see...