5sp EEC in an AOD car (EEC gurus needed)

[jwzg]

Alright: I've had the Cobra EEC and injectors for a while and was ready to put them in, when I got the idea that I'd better check out something before I went ahead with my big plans for Christmas.

I understand that the X3Z EEC is not supposed to be run in an AOD car. Why is this, and is there a way around it, as I am trying to retain factory drivablility with the 24lb'ers.? I know of a few people on another forum who've done this, but all of them have cars older than mine, and the wiring harnesses may be different. I've heard that the wire to pin 30 has to be cut in order to keep the EEC from frying and that codes cannot be pulled, but others have said it works with no problem.

Please save the lines about this processor being junk because it pulls timing on shifts (untrue) and using a different MAF. I'm simply wanting to know what needs to happen for it to work.

 

[jwzg]

Bump

 

[88 Fox GT]

The transmission should do okay, but the computer is the part I wonder about. The computer needs to know what kind of transmission you are using. I have a special wiring harness for my Mustang, which came with transmission ID plugs. You would connect a hot lead (either Manual or Automatic) to a ground. It would tell the computer what kind of transmission you are using. I don't know how you would do this on a stock Fox wiring harness. So, I'm not sure if the engine would even run until the computer knows what tranny your using, if you know what I'm trying to say.

 

[tmoss]

There is a hardware difference between an auto processor & a manual processor. The difference is because of the way the NDS [neutral drive switch,manual trans] & the NSS [neutral safety switch, auto trans] are wired. They are both wired to the same pin#30 but the auto trans wiring grounds the pin to the starter solonoid & the manual grounds to signal return, during crank mode there is a voltage spike sent to pin-30 so the auto trans processor has a diode on pin 30 where as the manual processor doesn't, most of the time this won't cause a problem unless you get into a prolonged crank condition. If your using a manual EEC in a auto harness, cutting the wire to pin 30 will keep the “signal return” pin 46 trace on the EEC board from frying, but you won’t be able to pull codes after that.

 

[wht93gtEd]

wait, I don't mean to hijack your thread, but I just did a 5spd swap and I left the auto computer in. So I have the auto computer on a 5spd car. Is there any problem with that? Or should I change the computers? I've heard about not being able to use a manual computer in a 5spd, but I haven't heard anything bad about using an auto in a 5spd.

If I do need to change the computers, can I just switch the computers, or do I have to change the harnesses and so forth?? THanks in advance for your help!

 

[tmoss]

The problem arises from using a manual EEC in a auto car harness.

 

[wht93gtEd]

The problem arises from using a manual EEC in a auto car harness.

oh man, you had me worried there for a moment. I'll just leave the auto computer in. You had me thinking that I was going to have to cram my 6'6" self under the dash again. Now I can relax. THANKS

 

[jwzg]

Whoa Tom. You're pretty sharp. Is there a way to keep this from being a problem by putting in a very low amp fuse or something? I'd like to be able to still pull codes. Perhaps a switch is in order.

 

[tmoss]

Whoa Tom. You're pretty sharp. Is there a way to keep this from being a problem by putting in a very low amp fuse or something? I'd like to be able to still pull codes. Perhaps a switch is in order.

I'd suggest taking the time to wire it up like the factory did. You can add wire without changing out a harness.

 

[jwzg]

Since I'm limited on time, can you give me help on getting started. I'm new to messing with the EEC and don't need any mini-disasters screwing up the holidays with the family.

 

[tmoss]

You can find my wiring diagrams at
www.veryuseful.com/mustang/tech/engine

the "88-91 EEC pinout" and "start circuit diagram" should be helpful.

 

[jwzg]

Tom, what would substitute for the neutral gear switch. Isn't there an similar switch on the AOD?

 

[tmoss]

Yep, like I indicated in my above response, the auto trans has a "neutral safety switch" that performs the same function as the manual trans "nuetral drive switch".