EEC IV Wiring Help Needed.
 

Ok, yes… another post with EFI Wiring questions. I have 4 areas I need some guidance with. I‘m about to install a 5.0 EFI in a 67 Mustang. I have a 88 speed density computer & wire harness, but I also have a 93 5.0 computer and plan on doing the mass air upgrade.
For now, I want to get things running with the 88 harness before I install the MAF upgrade.

AREA 1 EEC Relay
Some wires were cut at what I believe to be the EEC relay and they just tied wires together to get it to run (the BLK\ORN wire to pin 1 was left off).
These are the wires:
a) Orange \ Black….To unknown
b) Red….To pin 57 in the EEC (diagram says pin 37, is this ok?)
c) (2)Black \ Orang..One to Fuse link “always hot” and the other to pin 1 in the EEC (unused port??)
d) Black \ Lt. Green….To unknown
e) Red \ Lt. Green…….To unknown

If someone could shed some light on how the relay should be wired and where the wires I marked “unknown” go to, it would be a big help.


AREA 2 Wire Color Codes
Based on Haynes and Autozone wire diagrams, I have 10 wires going to the EEC that have different colors than the diagrams show. Some are similar and some are not, but they do appear to be from the factory. I couldn’t find an earlier or later wire diagram that matched my harness. Is this normal?

AREA 3 fuel pump relay
The relay on the 88 harness was placed under the hood on the pass. side inner fender. I remember when I built my Factory Five Cobra, it was under the seat. Are there two relays or did they change this location from year to year?

AREA 4 Green connector by the EEC
Gray Yellow…………….Hot on accessory
Black \ White……………Neutral Sensing
Tan \ Lt. Green………….Fuel pump relay
Red (I think)……………Inertia switch
Can you tell me if these are feed wires or source wires? (going into the EEC harness or headed out) I know that I have to tap into the oil pressure, temp sensor and alt charg circuits to the car. I have no problem chasing those down (for now anyway)

The following is in here for cut \ paste to help with your reply:
AREA 1 EEC Relay Wires:
Orange \ Black…...To
Red……………….To pin 57 in the EEC (diagram says pin 37, is this ok?)
(2)Black \ Orang..One to Fuse link “always hot” and the other to pin 1 in the EEC (unused port??)
Black \ Lt. Green….To
Red \ Lt. Green…….To

AREA 2 Wire Color Codes

AREA 3 fuel pump relay:

AREA 4
Gray Yellow…………….Hot on accessory
Black \ White……………Neutral Sensing
Tan \ Lt. Green………….Fuel pump relay
Red (I think)……………Inertia switch

I tried searching threads before posting this.:confused:
Thanks a million

Re: EEC IV Wiring Help Needed.
 

probably all the diagrams you need that are in color are here:

Mustang FAQ - Engine Information

Re: EEC IV Wiring Help Needed.
 

AREA 4
Gray Yellow…………….Hot on accessory
Black \ White……………Neutral Sensing
Tan \ Lt. Green………….Fuel pump relay
Red (I think)……………Inertia switch

Area 1
EEC Power Relay
Orange and Black wire splice into Red wire from pin 57
Red wire from relay to EEC is pin 37 and is correct
Black/Orange goes to pin 1 and too fuse link to starter relay!!!! NOT BATTERY
Black/Lt. Green go to battery ground terminal, also pin 40 on the EEC
Red/Lt. Green tap into your ignition coil wire, TFI Module, and to a fuseable link.

AREA 2 I heard that the wire color codes can very a little depending on supply at the time the harnesses were made.

AREA 3 The fuel pump relay did change locations

AREA 4 Green connector by the EEC From what I can tell is that they are going into the computer.

I hope the info helps, I had a friend at a drafting company blow the wiring diagrams up onto 3 foot by 4 foot drawings. Much easier to read. Good luck.

Re: EEC IV Wiring Help Needed.
 

They vary by year too..........