EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Topic: EEC-V cougar to EEC-IV 5.0 HO, can it be done? (Read 2430 times) previous topic - next topic

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

March 20, 2006, 09:04:35 PM

I'm skeptical because I'm a newbie. I have done a lot of research on this and since I am good w/ electronics(my biggest woory), I have hope and determination, and this should get me through w/ a little advice from guys like you.
O.K. to the point, here is my situation, I have a 1996 3.8 V6 cougar. I love this car, so much that I could afford to buy a new car, but don't want one. I want this one! However, a V6 is just unnacceptable for a toy car.
My biggest concern w/ this project is what I stand to lose by pulling out the EEC-V(if that is what's in it) wiring harness and replacing it w/ the EEC-IV harness from 87 cougar 5.0 w/ SD & computer from the 92 mustang. I have already addressed the MAF conversion, but I'm concerned about the gauges (check engine light, speedometer, etc..), the ignition wiring, and what will not work afterwards (AOD-E?, airbag[not too worried about this], etc..).
These things seemed to have thwarted my plans, and I'm not ready to give up on this. I am willing to rewire the pins on the EEC-IV to mate w/ my system, no direct plugins necessary, as long as I know they are all going to the right places and I know what I stand to lose ahead of time.
Any advice you guys can give would be immensely appreciated.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #1 – March 20, 2006, 09:06:42 PM

Hey, I like this guy, you should help him out!

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #2 – March 20, 2006, 09:16:04 PM

what you are suggesting is possible, but you'll be much better off using a 1991-1993 5.0L cougar/tbird engine and harness. In fact, what would be ideal is to use a 1991-1993 cougar t-bird engine and harness, keep your current tranny (4R70W) and use a 1994-1995 5.0L mustang auto processor. You'll only have to do minor re-pinning to integrate the harness and processor, it will fit your car because the harness will be from the same chassis, and best of all you'll retain the computer controlled tranny.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #3 – March 20, 2006, 10:10:14 PM

OK, great!
i was just wondering about moving in this direction!
So how does the newer harness, or computer accomodate the tranny? Is this system EEC-V based or are there just different pinouts and programming on this model EEC-IV?

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #4 – March 20, 2006, 10:39:01 PM

It's still an EEC IV, but with only slightly different pinouts and programming. The 1991-1993 cougar/bird harness does not have any wiring for the tranny. However, that harness is what is what eventually evolved into the 1994-95 5.0L mustang harness. So in order to accomodate the tranny you only need to do minimal re-wiring. It has more similarities to that harness than the 87 cougar one. Plus the intakes will fit under your hood. The '87 one won't.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #5 – March 20, 2006, 10:43:34 PM

OK I understand now that the 94-95 had an eec-IV, but with some serious issues, like retarded engine timing at wide open throttle, different pinouts, not accepting cam changes well, etc..
So, is there another year model eec-IV that could be used? are ther any mustangs from 87-93 that had 4R70W tranny's?
If not anybody have any ideas about how I can make working w/ the 94-95 EEC a smoother process?

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #6 – March 20, 2006, 10:45:35 PM

That's a myth. The only thing valid in that statement is the pinouts are different (only slightly). An EEC with the right tuning can do whatever you want to do.

http://forums.tccoa.com/showthread.php?t=69247

I stand corrected actually, the 94-95 auto processor does retard timing before shifts. But as stated a tune can always eliminate that.

make sure you read the whole thing, specifically the post by "lonnie". He runs the probably the most reputable EEC tuning business in the ford world right now.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #7 – March 20, 2006, 10:47:49 PM

If I found that aquiring a 91-93 harness was difficult, other than wire lengths, how much work would go into converting this 87 harness (post MAF conversion) to accomodate the 94-95 EEC and E transmission?

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #8 – March 20, 2006, 10:50:11 PM

I can't tell you exactly, because I've never tried it or heard of anyone trying it. Obviously if you're good enough, you can make anything possible. I would guess that the major complications would be more of adapting the fox harness to operate in an MN-12.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #9 – March 20, 2006, 11:19:14 PM

So lets say I go w/ a wiring ahrness from a 91-93 cougar/t-bird.
What changes are necessary to accomodate the harnees as far as guages, ignition, the 4R70W, and which 94-95 ECM am I looking for?

and on the 4r70w what pins are directed to the tranny?

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #10 – March 20, 2006, 11:27:07 PM

That diagram is for a manual tranny processor so there are no pins for the tranny. You'd have to get a diagram for an auto tranny (I believe UP-40 is the catch code). Since you'll be starting with a T-bird cougar harness, there will probably be little to no modifications necessary for the gauges and what-not. As far as the tranny there is a bit of modification necessary. The EEC-IV cars use a plug and play harness for the tranny. The EEC V's use a motherboard. You can interchange the two (use a EEC IV to control a EEC V tranny) but you need to know how to re-wire it. There is also an article on that site on how to go about that procedure. To put it plainly, you're asking this question on the wrong site;)

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #11 – March 21, 2006, 12:24:49 AM

Just throwin this out there....why not use a harness and what not from a 5.0 HO Explorer? They were EEC-V and used a 4R70W auto.

Re-wrapping a harness so it fits seems to be much easier to me than repinning and figuring out how to make an EEC-IV shift a 4R70W in an EEC-V car.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #12 – March 21, 2006, 12:30:04 AM

that sounds like an outstanding idea!
any downsides to this?
And which EEC-V cshould i use? Could I get the explorer ECM and just reprogram?

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #13 – March 21, 2006, 03:21:01 PM

The Explorers do use the DIS setup, but I doubt location of the EEC and such is in the same location as the MN12. I'm with Bill on bettin the '94-'95 Mustang setup is going to be the easiest.

EEC-V cougar to EEC-IV 5.0 HO, can it be done?

Reply #14 – March 21, 2006, 04:44:03 PM

Thanks for the input guys, I really appreciate your advice on this.
What I'd like to know more about is repinning the 91-93 cougar/t-bird harness to work w/ the 94-95 mustang and control the 4r70w trans.
This would be a big part of my installation.
Also, I have heard a lot of not so good things about the 94-95 5.0's.
are these complaints based onthe engine itself or the ECM and its programming. Because I planned to build a 5.0 w/ a used block and just slap some aftermarket heads, intake, distributor etc. Will this 94-95 setup work w/ just basic aftermarket hardware or will I need the special more expensive 94-95 parts?