i am swapping my 92 over to mass air for the 302 i am building for it.

the questions i have are.

i went to a junkyard and got 2 1994 maf truck complete engine harness' from the firewall forward. can i swap out the engine harness from the 92 and use the 94?

or would it be better to isolate the injector wires from the 94 harness and make an overlay harness for it? and pin the overlay into the ecc connector? i also got the computers from both trucks.

i have searched and never really found my question answered.

thanks

dt

 

I personally would use the mass air engine harness and EEC "as is" with the new engine, then make any adaption, if necessary, to the body harness connectors on the firewall.

If I remember correctly, and it's been a long while, it's much less work.

 

sweet so i can just directly swap harness for harness aslong as i use the complete 94 from the firewall forward correct?

the only difference i saw was the cruise control connector and it had an extra pressure sensor for the a/c on the back of the compressor. but i can work that out without too much issue i think.

both trucks were reg cab pickups as is my 92 that is recieving the maf.

 

Probably, but before you plug anything in you need to compare wiring diagrams to make sure what is on one connected is expected on the mating connector.

Both the EEC and the body connectors are the same from 92-96 but that doesn't necessarily guarantee they are pinned out the same.

1992-3 5.0L engine harness:


1994 5.0L engine harness:


Print out both diagrams, and on a notebook page make three columns - the first column is the pin number, the second column is what it does on the 92-93, and the third column is what it does on the 94.

At quick glance, I only noticed the 94 had additional pins used and the rest looked the same - though I just glanced.

That's the advantage of swapping in the entire engine harness and the EEC together - you don't have to do the above - plug and play between the two.

What you do have to do then is find the wiring diagrams for the body harnesses of 92-93 and 94, and compare those.

They may not be the same because the ABS was different between the years and I also believe 94 had an airbag in the steering wheel. Those 94 features might ride on unused pins on the 93, or Ford may have moved things around.

And that's why you need to compare diagrams first - even if the end result is everything is a match. Better to spend 20 minutes futzing with paper, than 5 minutes putting out a wiring fire in your truck.

Sorry I don't have the body diagrams handy... I could only find the engine diagrams. This is probably why guys tend to "peel" the earlier harness apart and add the pins/wires from the new harness for the additional injector wires and the MAF wires, but then you have to reloom the engine harness to make it neat and protect it.

I'd rather just use the new engine harness as is, and compare the body harnesses, because then returning to stock, should you want to, is that much easier. Plug in the old EEC and the old harness and rip off the MAF for your new(er) truck.

Two schools of thought to solve the same problem. Either works.

 

thanks a bunch man.

i did get bored and since i had 2 sets of identical maf engine harness' i took the one in worst shape and started stripping it down and made it into an injector only harness. my thought was i could run it to the eec and use it as an overlay harness and incorporate the MAF harness into it and leave the factory harness on the truck because everything works and it would elimate the cruise issue id have to work around aswell as the body pin out issue. would that be similar to the mass air kits you can buy?

if it doesnt work i have a 2nd harness i will use.

i have pin outs that you provided so i guess what i have to do now is to look thru them and figure out what is different on the eec pinouts and figure out how to swap the firing order to a 92 truck order. unless.....if i order a camshaft with the HO fire order i can keep the factory injector positions.

the only reason i am doing the maf swap is to get better driveability and tuning with the new 302 with gt40's and i have to pick a good non roller cam for it.

 

That's what the mass air kits are. Some wires, some pins for the EEC connector, connectors for the individual injectors rather than bank injection, and of course the MAF sensor. Remember, when doing a mass air converstion, the MAP sensor stays but isn't attached to the intake manifold any longer. It just "hangs" in free air.

Here are the firing orders post '82.

5.0 1-5-4-2-6-3-7-8
5.0 HO 1-3-7-2-6-5-4-8
5.0 Truck 1-5-4-2-6-3-7-8

And, here is how the cylinders are arranged:

Firewall
4 8
3 7
2 6
1 5
Front Bumper

Driveability and tuning are the big reasons most people convert to mass air.

The reason is very simple. Speed Density systems measure vacuum and throttle position to use as a way to calculate what the air volume rushing in should be, then add the appropriate amount of fuel.

Mass air system measures the air volume rushing in, and applies the appropriate amount of fuel.

It's taking a direct measurement of one of the most important engine parameters rather than calculating it from a data table comprised of assumptions.

Knowing something is always better than guessing

 

This swap almost seems to easy. I mean just add some wires and a sensor. Few hrs tops and its done. The f150 computer im using was a single o2 maf truck i think. The iat in the airbox does t need to be pinned in?

I appreciate your help and time man its helping alot.

 

Also a question about where the + voltage for the injectors comes from the eec or keyed on source.

 

Any ideas on my last questions?

 

Power to injectors provided key "on", computer provides the ground.

 

Sweet that simplifies things
Iguess all i need to do now is swap the firing order on tue harness

This truck only had one 02 is tht normal on 94 maf trucks?

 

what tranny is in the truck? did you check out the harness's on fordfuelinjection.com that are like 200 bills and takes all the guess work out of it?

 

The truck it came fom was e4od.

Ill get a new computer for sure. I did not know they made harnesses foe 200 bux id buy one in a heartbeat. Ill chwck it out thank you

 

I think tmrws project since its gonna rain hwre is toget started on putting my harnein the truck. Its not my DD so it doesnt matter if i have it down for a few days it wont be back out till spring anyways. I keep it in the garage all winter anyways lol

 

I think that the injector +12V source is the EEC relay. It's the same circuit that also feeds the VPWR pins (37 + 57 I think) on the computer.