I turned my EEC in for a re-manufactured one over a year ago and have been unable to retrieve codes from it. This is not a wiring or vehicle problem.

I had replaced the EEC and now unable to pull any KOEO or power on codes. Yes before you ask I have tries many methods and tracked out the wires, fuses, relays. I think its the incorrect EEC.
I need to determine the definitions on the EEC sticker.

Replacement
EEC-IV EFI-SD42F program code ZAK0
F4TF-12A650-AXA G
64ESF42R50 9749 -12 3G01

Here's the question--the third line is different from the original EEC I had? What does this third line state specifically?

Original EEC
EEC-IV EFI-SD42F program code ZAK0
F4TF-12A650-AXA G
64ESF42R50 8481 -27 3M07

What is the difference from the the two? I'm betting new one (-12) is MAF and (-27) is Air Density.....

Can anyone confirm or deny this?
Would this difference be be cause of the communication problem?
i have found many pinouts that say so for the EEC
here is oneFord Fuel Injection

let me know your ideas?

 

I don't know if this will be much help, but found this the other day when looking for some info.

Fuel Injection Technical Library » EEC Program Codes

 

No they're both SD computers, if the replacement was MAF it would have the letters SFI where you have SD and the motor would run like crap because the injectors wouldn't be firing most of the time... all Ford MAF V8 computers also use sequential injection.

Both of the computers you listed are '94 vintage is the truck also a '94?

 

yes it is a 1994 5.0 (HO) manual transmission F-150 XL stock truck no mods. I just cant see why the new computer just wont run the KOEO codes.

what are the last line of numbers on the label mean and why are they so different?

This is the third ( first replaced with the -27 and the second was sent back to get repaired same one returned) I have put in but since I replaced it I have been unable to pull codes.

The last box only lasted just about a year before issues arose. It started to buck when driving and then finally just died when it got to operating temperature till it cooled.

 

I don't know but the only part that matters is the program code and they're identical.

Your problem could simply be a displaced pin in the EEC connector, it would be worth it to disconnect the harness and have a look, just be sure to disconnect the battery first.
Pin 17 is for the MIL or check engine light
Pin 48 is the STI or Self Test Input.

Also verify that the bulb isn't burned out for the CE light.. it should illuminate when the ignition is first switched on.

If it turns out there is something wrong with the wiring between the EEC and dash light you could probe the MIL wire with a multimeter or test light and count the pulses that way.

 

All Ford Computers in trucks from 1985-1995 use the same pins for the MIL (17), STI (48) & SIG RET (46) at the computer plug. These are the three pins used during the self-test to flash the MIL light in the cluster and give information to the code reader.
Some computer applications do also have data pins (Data - #915 & Data + #28) to give information for a scanner if you have one of those.

There is also a fuel pump relay coil computer pin #22 at the self test plug pin #6.

 

yes the bulb works see it when I turn the key and have tried a multimeter off the STO Connection. NADA... I have a simple Actron CP9015 reader that beeps and flashed off the code. But when I hook it into the EEC connector it beeps even before I switch the unit on or the truck Key on. really strange.

I have ran the KOEO wires used in the test with these results.

Ignition OFF and ON
STO(17) to Sig Return(46)
=OFF= 15.9 ohm & 0.003VDC =ON= 2.378ohm & 0.208VDC
Sig RTN(46) to STI(48)
=OFF= 2.95 ohm & 0.034 VDC =ON= 2.789K & 4.78 VDC
STI(48) to STO(17)
=OFF= cont tested at 0.181 and Ohm just flashed open (OL) and 0.333
& 0.36 VDC
=ON= cont was open (OL) and 2.869K ohm & 4.99 VDC

Looking over my wiring diagrams I do see there really in no difference from the wiring of 4.9, 5.0, 7.5 except one or two things. But the KOEO are the same. So why is the KOEO not working?
Only thing different it the EEC from when it worked before. I just cant understand why.

I just dont want to burn another 200 on a comp when this is under warranty. especially if its their screw-up.

As a last resort I think Im just gonna take the beast to FORD and see if they will work on it. Im betting they will laugh at me and tell me the same as before. Get a replacement computer from the junkyard they cant work on my old truck.

 

Hope you aren't ohm'ing out those circuits with any of those going directly into the EEC...that's a sure fire way to burn a 'puter up...

Pop open the EEC and see if it is failing...or send that one back...junkyard isn't a better bet.

I opted to buy the Equus code reader, for simplicity. It might be time for new/remaned 'puter judging from your problem.

 

This one was supposed to be a re-manufactured unit nut have had issues since owning it. Just got it returned from being fixed. "FIXED" but it still remains unable to communicate. Well I guess my only option left is dealership and see what they say. Thanks for Ya'lls help.