DIY Ford Mustang EFI wiring harness conversion- GETTING UGLY

[broncosbybart]

Has anyone seen a step-by-step guide for operating on the factory MAF EEC-IV harness? Would there be any benefit in doing one, if one doesn't exist. I think I'm going to take the plunge on mtfit's old 77 and am planning to use a factory uncut engine harness. Right now I'm just gathering info before it goes under the knife.

I've been to all the big EFI sites, so don't bother to list oldfuelinjecton or similar sites. Just curious to see if anyone has put a comprehensive list together of parts and supplies needed as well as an easy to follow guide. Advice is appreicated. Thanks.

 

[KyleQ]

It isn't hard to do, once you plug everything together there are just a few grounds and power wires.

Your best tool is just going to be to look at a pin out of the plug and go from there. The harness will lay out how it did in the Mustang and that will also help.

 

[br0nc0xrapt0r]

It isn't hard to do, once you plug everything together there are just a few grounds and power wires.

Your best tool is just going to be to look at a pin out of the plug and go from there. The harness will lay out how it did in the Mustang and that will also help.

So plug it all in and snip the rest? I'm looking to do the same.

 

[1sicbronconut]

http://www.broncofix.com/viewtopic.php?t=261594 and http://www.broncofix.com/viewtopic.php?t=261589 some orginal write ups from back in the day, I did my first swap back in 99'

 

[ransil]

I have started one, most of it is chicken scratched on some paper and some is in my head.

Sent from my Galaxy Nexus using Tapatalk 2

 

[KyleQ]

So plug it all in and snip the rest? I'm looking to do the same.

There will come vacuum BS to cut by where the harness come through the firewall and the two airbag sensors can go. There is also the air pump crap you can leave unplugged along with the A/C and EGR crap on the drivers side of the motor.

Just ensure you plug in all of the major stuff-
PCM
Fule Injectors
O2 Harness
TPS
TFI and SPOT
IAC
MAF
Temp

Super easy to 3G it right away, cuts out a lot of clutter on the pass side of the Bronco.

 

[ILikeBond]

I'm looking to do the same.

Ditto. If you do it and have a chance, please take lots of pictures and post a how-to for those of us, like me, who are wiring-diagram illiterate and not terribly familiar with the whole EFI system beyond reading through oldfuelinjection.com.

 

[hyghlndr]

With as popular as the conversion is, I can't believe someone has not done a setup by step with pictures "dummy" version. Anyone know of one?

 

[ransil]

With as popular as the conversion is, I can't believe someone has not done a setup by step with pictures "dummy" version. Anyone know of one?

That is what I was aiming for a dummies guide

Sent from my Galaxy Nexus using Tapatalk 2

 

[misterkeebler]

Look for the old ford Motorsport install manual harness manual, you used to be able to buy it from ford for $5.00. Their harness was a 93 harness and you cut off the brown and green connectors and wire constant hot, run hot, crank only hot and crank/run hot. It's a pain because the factory switch doesn't have a crank/run hot so I ran a couple diodes to achieve it. If I have the chance I'll post the part number for the manual, or the wire colors for splicing. I left the tab and tad plugged so no CEL on but left the vacuum lines unplugged. You can hardwire resistors into the harness to eliminate the and clean up the bay some. Because the wiring is set up for a mustang it's a little bit if a pain to lengthen the wires to where you need them but if you already have a harness it is worth it compared to an aftermarket harness. The summit harness looks to be a clone of the factory harness with slightly different connectors and you can check out their install instructions at the website and probably figure out the wiring from there

 

[Broncobowsher]

motorsport once had instructions.
Before you get too far along, check the connectors and see if they are still usable. A lot of them have gone all crusty and self destruct when unhooked. When that happens the insulation on the wires usually isn't far away. Then it is new harness time.

 

[00gyrhed]

I you cant find the exact year on the internet (which I doubt) go to the library and get a pin out diagram for the year model efi you are using. Took me about 10 minutes and a helpfule librarian to get it at the little local library. Everything you need is there on the pin out diagram. Thats why no body publishes a how to. If you cant follow the pin out you probably couldnt follow the detailed how to. you can use the pollution device monitoring removal tricks on the ford fuel injection website and buy the right resitors at Fry's and some times readio crap but you can buy all you need to do 4 or 5 for the price of one resistor at radio crap.

Anyway its like others have said the harness will plug up to everything and then there will be some loose ends like the pollution devices, the AC harness, sometimes the alternator harness and then the grounds, battery, ignition and start signal. I think thats it. It took me longer to go to the library and find the pinnout than it took to ferret out the right wires once I had the pinnout.

I recommend you take out the 10 pin plugs and solder and heat shrink every connection
you make.

Basically if you can't wire a cd player dont even think about this. But even if wiring baffles you the pinnouts are clear and as long as you develop a methodology and trace out the indivdual circuits and finish the work on each before moving to the next even a novice could do it but it will take longer. Every wire is color coded just blow up a pinnout and mark the wires you connect to the fuse realy etc with the new wire color so you will have what you did later if you need to trouble shhot something.

 

[br0nc0xrapt0r]

I you cant find the exact year on the internet (which I doubt) go to the library and get a pin out diagram for the year model efi you are using. Took me about 10 minutes and a helpfule librarian to get it at the little local library. Everything you need is there on the pin out diagram. Thats why no body publishes a how to. If you cant follow the pin out you probably couldnt follow the detailed how to. you can use the pollution device monitoring removal tricks on the ford fuel injection website and buy the right resitors at Fry's and some times readio crap but you can buy all you need to do 4 or 5 for the price of one resistor at radio crap.

Anyway its like others have said the harness will plug up to everything and then there will be some loose ends like the pollution devices, the AC harness, sometimes the alternator harness and then the grounds, battery, ignition and start signal. I think thats it. It took me longer to go to the library and find the pinnout than it took to ferret out the right wires once I had the pinnout.

I recommend you take out the 10 pin plugs and solder and heat shrink every connection
you make.

Basically if you can't wire a cd player dont even think about this. But even if wiring baffles you the pinnouts are clear and as long as you develop a methodology and trace out the indivdual circuits and finish the work on each before moving to the next even a novice could do it but it will take longer. Every wire is color coded just blow up a pinnout and mark the wires you connect to the fuse realy etc with the new wire color so you will have what you did later if you need to trouble shhot something.

So you are saying one would be best off using a pin guide and a tester to identify plugs and eliminate useless ones and identify needed plugs for sensors and the condition of said plugs? Sounds too easy I don't trust you or your witch craft.

 

[br0nc0xrapt0r]

Pin guide in an image on this page.

http://oldfuelinjection.com/?p=3

and pin out guide

http://oldfuelinjection.com/5.0Lpinouts.html

As easy as this seems I am not going to attempt it without the help of the tech ninjas at work.

 

[misterkeebler]

If you give me a day I will post a wire breakdown

 

[broncosbybart]

Well, I started on my harness. Didn't get very far, as I found out that it is missing the oxygen sensor harness. I did remove all the tape and split loom. Even my partly colorblind eyes can say that the number 1 pinout isn't yellow like what the oldinjection website says.

 

[brianstrange]

Well, I started on my harness. Didn't get very far, as I found out that it is missing the oxygen sensor harness. I did remove all the tape and split loom. Even my partly colorblind eyes can say that the number 1 pinout isn't yellow like what the oldinjection website says.

No biggie, just buy two 02 pigtails, and wire them in behind the manifolds. I usually reroute them anyway.

 

[broncosbybart]

I think my biggest question so far is on how to wire the 4 pack fuses and relays into this thing and how much extra wire to add or remove from some of the plugs

 

[brianstrange]

If you're not cutting anything off the harness, it's quite simple.
1) get a 25 amp fuse for the black & orange wire off the solenoid. This powers the KAPWR, EEC, fuel pump and engine actuators.
2) Supply 12v+ fuse circuit with a relay for the gray & yellow 02 sensor wire, fed at the green connector by the EEC
3)The large round grommet going thru the drivers side firewall has the oil pressure, engine temp, 12v start and 12v run, and the 12v start going to pin 30: Red/Blue gets 12v+ during start, Red/Green gets 12v+ during run The Purple wire gets 12V+ during start (before the NSS), White/Red is oil pressure and Red/Yellow is engine temp (and possibly VSS too)

There may be a fuel pump monitor wire on this circuit as well as the diagnostic.... These will need to be traced and rewired as needed.

4) install/rewire FP relay and inercia

Note: The fuel pump relay will be controlled by pins 19 & 22 on the eec. Make sure you note how the inertia switch is on your harness. I believe it's in series off your actuator circuit to provide switching power to the FP relay.

 

[ransil]

here is the motorsports manual

http://documents.clubexpress.com/do...3I8HbUztpYDYLORFevg+gnQE6Xv5gxu7jEs6s2VLTpAs=

lot of good ideas thrown around here & there but again it comes down to exactly what to do and where.
you will find wire colors vary harness to harness.

here are the basics.

strip down harness, zip tie loosely at all branches to keep shape

Inspect all wires including the factory splices

Inspect all connectors , tabs & locks get broken, the EEC connector plastic get brittle with age and the pin lock will break. learn how to unlock & remove pins, get spars at the junk yard

replace all the ford connectors you need to connect to your vehicle with weather packs, usually just the green one ant the one with the oil & water in it

identify what will not be used ( tab,tad, egr, purge AC wot) either remove completely or trin back to a central location & terminate with resistors so codes are not throw.

remove all fuse links replace with fused relays, share the load probably does not matter what is shared, but think about sharing same type of circuits.

Install harness into vehicle to figure out where your putting stuff & routing ( computer, fuse block, relays)

read and understand how to wire the NNS pin 30
http://classicbroncos.com/forums/showthread.php?t=172541&highlight=pin+auto

salt & pepper connectors, I usually clean & inspect them and put on conductive paste, I have removed them also, both way work IMO

Make a good common ground somewhere and run all you grounds to it.
I use these:
http://www.delcity.net/store/8-Point-Junction-Block/p_801580

when you done test it before warping up the harness
use harness tape and loam to wrap up the harness NOT Electrical tape, RJM sells it 3 rolls will do it get 5 just in case.

RJM harness is a good deal, all new parts buy it and drop it in.
I would not spend any money on paying someone else to rework an old harness figure $300 rework + $100 avg for a used harness you might as well buy an RJM harness.

cost of reworking a harness your self is about $50-75 for parts + free time, weather packs, loom, tape, fuse block, misc wire, ground blocks