My Mustang EFI Stock Harness Rewire diagram

[JohnJohn]

It has been a bit slow at work so I took a Visio file that was sent to me based on a Mustang 88-91 EFI harness and decided to try and adjust it for a Bronco or any other old car for that matter. I am about to rewire one for my trail rig to try and save a few bucks.
I read a lot and will credit people as I remember names but RJM has so much good info.

I do have a couple of questions for the EFI gurus.
1. Can I just remove the EGR EVR, CANP, Air Management 1 and 2 wires and connectors or should I wire in a 73 ohm resistor it the connectors place to keep soft codes from showing up?
I read where I could soder a 73 ohm resistor in to avoid the codes but wanted to ask for advice.

2. Can I just not hook the pin 30 Neutral Drive Switch (NSD) wire up to anything, or do I need to connect it to the pin 46 Signal Return when not in neutral? it looks like pin 30 gets 0 volts when in Neutral and 0.1 when in gear.

Let me know what you think of the diagram and my list of wires to remove.

Link to modified harness diagram PDF

List of EEC wires to remove First color is primary color, second color is stripe color
Wire pin # color/size end point
33 Dark Green 18ga EGR -EVR
31 Gray/Yellow 18ga CANP
38 White/Red 18ga AM1
32 Light Green/Black 18ga AM2
10 Pink/Light Blue 16ga ACCS (AC system)
54 Orange/Light Blue 18ga WAC (AC system)

 

[00gyrhed]

1. The Smog stuff will show an error code if you just disconnect. The EGR position need three resistors in a dleta pattern to fool the computer. Old ford fuel injection has a diagram and the right sizes. $20 at radio shack $3 at frys or over the internet.

If you are going to take it to a tuner anyway dont bother they can alter the ECM to not look for the smog stuff.

2. I wired mine direct to ground. I want to be able to start it when its in gear. But you can put it on a hidden switch as kind of an anti theft detterant.

Its not that tough to rerwire the Mustang harness. You can simply get a pinout diagram off of olf ford fuel injection and make sure everything on that diagram is hooked up. Its pretty much fool proof. Between the length of the iwres and the shape of the plugs you just hook everything up and then take out anything that isnt used. You will be left with a pile of grounds, a hot, a start, and a run wire.

Word of advice gound the hell out of everthing. I ran a 2 ga wire from the batterey to the frame, then looped it to the block, then to the fire wall, and then on in to the dash. All of the grounds from the EFI harness and anything else all terminate at one of these points. Way overkill but you NEVER have to worry about a sensor not reading correctly or a gauge screwing up. When I put in my nordsdog gauge cluster I had several issues that they blamed on grounding. So I emailed them a picture of my grounding system and that shut them up.

 

[Amac70]

pin 30 wirring is dependent on computer whether your running an auto or manual computer. this is one of the wires many people mess up on. do a search on that pin specifically.

http://classicbroncos.com/forums/showthread.php?p=1729822

 

[JohnJohn]

Thanks guys.
I did forget to mention that I have an RJM EGR delete plug for my EGR position connector.

I was quite proud of my diagram after a few fun hours in Visio.

 

[JohnJohn]

Also thanks to Randy Silbaugh for creating the original Visio draft I started with.

 

[ransil]

Jason/Rich helped too

should leave these in there they do more good than bad

33 Dark Green 18ga EGR -EVR
31 Gray/Yellow 18ga CANP

do you need the stencils\shapes for them

 

[allenfahey]

Randy is the man! Him and Steve are the "wiring guys" when we do the MEB Wrend and Roasts.

 

[JohnJohn]

Thanks Randy.
I was trying to replicate the super clean RJM harness that is on my 77 so I pulled those two out.

 

[ransil]

Thanks Randy.
I was trying to replicate the super clean RJM harness that is on my 77 so I pulled those two out.

I was going to use the layers in Visio to show different configurations that way there is one drawing to edit/ store

PIn 30 should be
Manual computer connect to pin 46
Auto Computer connect "I" terminal on starter solenoid or Ignition start wire.

 

[broncosbybart]

Excellent work! Subscribed!

 

[JohnJohn]

I will add in the pin 30 information and update the PDF on Thursday.

 

[JohnJohn]

https://www.dropbox.com/s/h2chfttl8rii6p8/89-92%20Mustang%20EFI%20Wiring%20Diagram%20-JohnJohn-v3.pdf
I updated the Pin 30 info for Manual computers or Auto Computers in the PDF link here and in the link from my first post in this tread.

 

[skerrybronco]

https://www.dropbox.com/s/h2chfttl8rii6p8/89-92%20Mustang%20EFI%20Wiring%20Diagram%20-JohnJohn-v3.pdf
I updated the Pin 30 info for Manual computers or Auto Computers in the PDF link here and in the link from my first post in this tread.

Thanks for this post, very helpful.
I have a couple questions as I am not the wiring genius and I would like to get my harness in this sunday while the wife is away.

1. Pin 30 in the diagram caption says to connect to start wire on I post,
I thought I was hooking up my violet start wire ( centech ) to the S post, do I still connect Pin 30 to the I post.?.

2. Pin 1 , do I just splice and solder off this wire to a fuse block for the four relays.?

3. Ignition Relay…. Ignition Start/Run 12v, confuses me does this come from the start on the ignition, separate from the power that triggers the other three relays.?

thanks in advance for your patience folks

Skerry

 

[skerrybronco]

https://www.dropbox.com/s/h2chfttl8rii6p8/89-92%20Mustang%20EFI%20Wiring%20Diagram%20-JohnJohn-v3.pdf
I updated the Pin 30 info for Manual computers or Auto Computers in the PDF link here and in the link from my first post in this tread.

Bump
Thanks for this post, very helpful.
I have a couple questions as I am not the wiring genius and I would like to get my harness in this sunday while the wife is away.

1. Pin 30 in the diagram caption says to connect to start wire on I post,
I thought I was hooking up my violet start wire ( centech ) to the S post, do I still connect Pin 30 to the I post.?.

2. Pin 1 , do I just splice and solder off this wire to a fuse block for the four relays.?

3. Ignition Relay…. Ignition Start/Run 12v, confuses me does this come from the start on the ignition, separate from the power that triggers the other three relays.?

thanks in advance for your patience folks

Skerry

 

[ransil]

Bump
Thanks for this post, very helpful.
I have a couple questions as I am not the wiring genius and I would like to get my harness in this sunday while the wife is away.

1. Pin 30 in the diagram caption says to connect to start wire on I post,
I thought I was hooking up my violet start wire ( centech ) to the S post, do I still connect Pin 30 to the I post.?.

read the link for pin 30 above, how to hook it up depends on the computer you have.


2. Pin 1 , do I just splice and solder off this wire to a fuse block for the four relays.?

It needs to be fused, pick one, I would do its own fuse

3. Ignition Relay…. Ignition Start/Run 12v, confuses me does this come from the start on the ignition, separate from the power that triggers the other three relays.?

Start wire is its own wire from the centech harness, purple
Run is another wire on the harness hot in run, I don't know the color.


thanks in advance for your patience folks

Skerry

see answers in the quote

 

[skerrybronco]

see answers in the quote

Thanks as usual Ransil
let me reiterate as I am a little dopey on the wiring but I am getting it slooowly.

1. Pin 30 will go to the I terminal on the solenoid, as it only has power at cranking, I have a A9P comp.

2. Pin 1 needs constant power to feed the comp, grab fused power from one of the relays

3. the three relays will get power when ignition key is on, I believe this to be my extra centech blue wire, I will check to make sure it only has power at on.

The ignition relay PLEASE CONFIRM gets power in crank only or Run only or Both

thanks again

 

[OX1]

I'd also extend out the wire for pin 27 (EGR position pin) to somewhere near drivers firewall area. Just in case you ever end up getting a Quarterhorse or other tuning device that uses that pin for input to data-logging for a wideband O2 sensor (assuming you are not going to run EGR of course).

 

[skerrybronco]

I'd also extend out the wire for pin 27 (EGR position pin) to somewhere near drivers firewall area. Just in case you ever end up getting a Quarterhorse or other tuning device that uses that pin for input to data-logging for a wideband O2 sensor (assuming you are not going to run EGR of course).

Thanks, I have the egr eliminator plug for the harness, not sure on the reach yet, but will probably mount in glove box or on fire wall

any comments on my # 3 question

 

[ransil]

Thanks as usual Ransil
let me reiterate as I am a little dopey on the wiring but I am getting it slooowly.

1. Pin 30 will go to the I terminal on the solenoid, as it only has power at cranking, I have a A9P comp.

2. Pin 1 needs constant power to feed the comp, grab fused power from one of the relays

3. the three relays will get power when ignition key is on, I believe this to be my extra centech blue wire, I will check to make sure it only has power at on.

The ignition relay PLEASE CONFIRM gets power in crank only or Run only or Both

thanks again

the ignition relay will need both, something needs to power the coil.

but I don't think you can just tire the purple & a run wire to it as the purple need to go to the pin 3 of the TFI plug and this cannot get any run power motor will run like crap and breakup at 3K rpm.

I have done a few of these I cant remember how I did them.

 

[skerrybronco]

the ignition relay will need both, something needs to power the coil.

but I don't think you can just tire the purple & a run wire to it as the purple need to go to the pin 3 of the TFI plug and this cannot get any run power motor will run like crap and breakup at 3K rpm.

I have done a few of these I cant remember how I did them.

Thanks Ransil
I think I have it figured out I had labelled my red/blue wire ( #3 tfi ) for crank only a while back....

so red/gr for #4 could have run power from the ignition relay and for #3 could I run it from my the I on the solenoid relay, or find another source for crank only.