converting from carb to EFI

[paul78zephyr]

I have plugs that look like they would be the mates to those plugs. What I need to know though is how many pins they each have mine are 4 pins a piece.

Rbuckley any way you can look at the 2 round connectors that are right next to the computer Check connector and count how many pins each one has?


Paul, you have been extremely helpful! Thank you Very MUCH!!!!!! You have really stuck in there to help me figure this out, and also to help me understand what I need to know. If I determine this is not an 86 underdash harness but is indeed an 84 harness I will get the 92-93 EFI harness so it has the brown connector then. I did find a part number on the part of the harness that is in the driver side kick panel and goes to the rear of the car before the plugs that attack it all. It started off with E4 then had 2 more numbers/letters.

I did compare some of the information I found on the other thread with things you have said recently such as what harnesses are the same and what not.

E4 part number can mean it is a 84 harness (and probably is) but it is possible that a 85 harness could still have a 'E4' number. I would look at your harness and try to see if there is any evidence that its been removed/replaced. Many times when harnesses are replaced they arent tied down under the dash the way they are at the factory. Id look for that.

A 92-93 EFI harness is the simplest way to go if you are not going to go 'all 86'. You will need to make connections to two connectors on a 92-93 unit - one brown (they can actually be reddish) circular connector that is on the engine compartment side and one green rectangular connector that is under the dash near the computer connector and EEC relay. Using the 92-93 harness (which is identical to FRPP M-12071-C302) allows you to use the FRPP installation manual which spells out everything you need to do. I have this manual and there used to be a copy of it online (bootleg) - but that link is now dead. Maybe someone else here has a good link to an online copy.

One other thing I meant to ask. On your two black '4 pin' connectors - are they really 4 pin or are they 8 pin connectors with only 4 pins loaded? Look carefully into the connector housings.

Paul

[fordfreak300]

My entire loom has been retaped. It has definately been out of the car.

A 92-93 EFI harness is the simplest way to go if you are not going to go 'all 86'. You will need to make connections to two connectors on a 92-93 unit - one brown (they can actually be reddish) circular connector that is on the engine compartment side and one green rectangular connector that is under the dash near the computer connector and EEC relay.

But what would I connect these too?

[CapriGT]

Heres a pic of the connectors courtesy of FordMuscle.com. This show both sides connected

[fordfreak300]

Ahh I read in the other thread what they connect to. I think I should just go with a 92-93 harness. I am not going to completely rewire my car when I can just splice in those connections.

Thank you again for your help Paul. You helped me to figure out what I need to do.

And also thank you Jeremy for spending so much time on the phone with me last night and taking all those pics for me.

[fordfreak300]

CapriGT, I was referring to where they were at in the picture that Rbuckley linked us too. Thank you for proving the picture though.

I really appreciate everyone's help here. I feel confident I can do this.

My next step will be to figure out how to wire in my MSD6a box as it is what I use for my ignition. I will be reusing it on my EFI conversion until I get an MSD 6al box. Which won't be until after I have completed the conversion and the car runs good.

[paul78zephyr]

My entire loom has been retaped. It has definately been out of the car.



But what would I connect these too?

OK, now we are finally at the heart of the matter. This is where alot of guys (me included before I learned about all this) find themselves lost. The wires at these connectors must be 'hard wired' into your car.

Assuming you are using a 92-93 EFI harness it will have two connectors that must be hard wired to - a brown circular with 8 pins (engine compartment) and a green rectangular with 8 pins (under dash near computer):

Brown
RED/LBLU to 12V crank only
WHT/PPL to 12V crank only
RED/LGRN to 12V crank and run
WHT/RED to oil press dash gauge
RED/WHT to water temp dash gauge
TAN/YEL tach 'trigger' wire
GRY/RED and PPL/YEL to manual trans neutral gear sw (NGS)

Green
WHT/PNK to low oil sender
GRY/YEL to 12V run only
DGRN/YEL to inertial sw then to fuel pump pos+
PNK/ORG to VSS neg and GND
GRY/BLK to VSS pos
PNK/LGRN to CEL. Other side of CEL to 12V crank and run

This is all from the FRPP manual. Too bad that online copy is gone.

And if you were to use another year EFI harness you would have similar (not exact) connectors with similar wiring requirements. Like I said, Im using a 90 EFI harness that I heavily modified primarily to eliminate the connectors on the engine comp side (the 90 has two connectors there) and take all those wires and combine them with the single green rectangular connector's wires (same conn as 91-93 but different wires) into one large new connector that is under the dash. I then made my own 'mini harness' to connect this new connector into the required points in my existing 78 Zephyr underdash harness. I also needed to add the fuel pump relay and circuitry.

Paul

Paul

[paul78zephyr]

MSD 6A or 6AL on Ford EFI system:

http://www.msdignition.com/pdf/6%20series/pdf18.pdf

or

http://www.msdignition.com/pdf/6%20series/pdf19.pdf

Paul

[CapriGT]

CapriGT, I was referring to where they were at in the picture that Rbuckley linked us too. Thank you for proving the picture though.

I know but that pic wasn't the best at showing what the plugs looked like.

[fordfreak300]

Yeah it is too bad it is gone. I think with the info from the other thread and the info you just gave me I should be just fine. It will be about 2 weeks before I can start getting all of the parts together but I expect to gather them fast. I am supposed to be working on my suspension right now and here I go converting to EFI. But for I am doing it for smog reasons. I will want to finish this as fast as I can so I can get back on track with my suspension plans.

[fordfreak300]

I know but that pic wasn't the best at showing what the plugs looked like.

Ahh I get ya, I was wondering where they were on that pic. I a going to use a 92 or 93 harness anyway now so that pic will not be of much help to me anymore.

[CapriGT]

Paul given that info it almost seems silly to completely rewire the car when all you need to hook up are a handful (or two) of wires to the existing car. Are the other years similar colors? What is the overall advantage to the 92-93?

[fordfreak300]

MSD 6A or 6AL on Ford EFI system:

http://www.msdignition.com/pdf/6%20series/pdf18.pdf

or

http://www.msdignition.com/pdf/6%20series/pdf19.pdf

Paul

That looks very easy, thanx again Paul. Man I wish I had all the parts right now I would be out in the garage starting already.

[fordfreak300]

Paul given that info it almost seems silly to completely rewire the car when all you need to hook up are a handful (or two) of wires to the existing car. Are the other years similar colors? What is the overall advantage to the 92-93?

I agree, I'm not rewiring my whole car for little amount of wires needing connected. I may even get the opposite side connecters from a slavage yard and splice the wires in so the connectors still work.

[paul78zephyr]

Paul given that info it almost seems silly to completely rewire the car when all you need to hook up are a handful (or two) of wires to the existing car. Are the other years similar colors? What is the overall advantage to the 92-93?

The two advantages of the 92-93 EFI harness are:
1. The fuel pump relay and circuitry is built into the harness.
2. It is the same as the FRPP harness and allows use of that harnesses installation manual which walks you by the hand through the entire installation process - wire by wire. You can still buy the manual for around $5-10

One last thing. I would recommend - if at all possible - to try to find a 92-93 harness set (EFI, engine, O2) from ONE car. That way you are certain it matches up. Dont forget that the O2 sensor harness is trans specific.

Paul

[paul78zephyr]

I may even get the opposite side connecters from a slavage yard and splice the wires in so the connectors still work.

Thats essentially what I did - except I combined them all into one connector (with more pins) that I located on the harness so it was under the dash.

Paul

[CapriGT]

Sorry for all the questions, but it's nice to have someone who has done this to explain it in terms we understand. And Foprd freak I don't mean to hijack

1. The fuel pump relay and circuitry is built into the harness.

So in this harness the relay which is usually under the driver's seat in part of the main Engine harness? I can see where that would be a definite advantage

[paul78zephyr]

Sorry for all the questions, but it's nice to have someone who has done this to explain it in terms we understand. And Foprd freak I don't mean to hijack



So in this harness the relay which is usually under the driver's seat in part of the main Engine harness? I can see where that would be a definite advantage

NO. Its located on the EFI harness. Engine harness is different. See my overview near the beginning of this thread.

Paul

[CapriGT]

sorry, I knew what you meant, but said the wrong one.


Is this the manual you were referring to?

http://static.summitracing.com/globa...m12071f302.pdf

[paul78zephyr]

sorry, I knew what you meant, but said the wrong one.


Is this the manual you were referring to?

http://static.summitracing.com/globa...m12071f302.pdf

Thats it! Good call on Summit!

If your doing a 92-93 harness thats your bible.

Paul

[CapriGT]

I downloaded that to my collection of diagrams so I should be set.

[fordfreak300]

CapriGT there is no hijack here, your asking questions about the same things i am. You may ask something I do not. No reason why we can't both learn at the same time. Good call on the manual I downloaded it as well. Free is very nice

[fordfreak300]

Where do the computer mount anywa? Passanger side kick panel?

[v8only]

that's the factory location, with that short harness it won't go too many other places.

[fordfreak300]

ok then that's where I'll put it when I get it. I was thinking if it went somewhere else it might just end up there anyway. Easy to get to.

[Dean_T]

May I also recommend the book "How to Undestand, Sevice and Modify Ford Fuel Injection & Electronic Control" by Charles O. Probst. (for '88-'93 Ford, Lincoln, Mercury and light trucks).

It has the wiring diagram for each year of Mustangs but unfortunately, you'll have to sift through Mazda and other crap to get to the specific parts regarding the Mustang EEC-IV system.

I like it because it has drawings and explanations of all the sensors and connectors.

ISBN 0-8376-0301-3

By the way, the '84 Mustang has the "well" in the passenger door jamb to mount the computer. It's not exactly the same configuration of the '89 Mustang but I think it's big enough to mount the computer and avoid a wire harness in that area.

Unlike my '83 Fairmont which has no well and a narrower door jamb structure. I'm going to have to slice and weld in a section from a donor Mustang.

Dean T