ATX --> MTX Conversion Information

[Joe_SHO]

Thanks for the pic. Would it be plug-and-play for same year cars?

(Apologize for all the n00b questions, and appreciate all the answers.)

 

[rubydist]

No, the connector is populated differently between the atx and mtx, even for the same year.

 

[Joe_SHO]

I plan on using the MTX computer. How did you know which wires to switch? I have the Chilton's manual, and on pages 6-142 and 6-143 it shows the wiring diagram for each computer. Is it a safe bet to pull out ALL the wires from the connector, and re-insert them into the positions they're supposed to be on the MTX computer? How are the positions numbered on the connector? What happens to LT GRN/PPL? (I don't see it on the MTX diagram anywhere.) Thanks again. -Joe

 

[rubydist]

You actually need the right connector, or will need to modify the keys on the connector - even though they are the same size and number of pins, they are keyed differently, so the mtx and atx harnesses don't physically plug together - I suppose you could grind off the tab that's in the wrong place.

I don't know if the Chilton's diagrams are correct or not.

 

[Joe_SHO]

Phoenix - any answers? Did you use the Chilton diagrams to redo your wiring? How did YOU know which wires go where?

 

[gmail]

Yup it works with the D4U1 (atx) but on my part with the poor Tweecer support with the ATX ECU I decided to put MTX wirerings and ECU. You will need both EVTM manuals (if both harnesses are diff years) and match all the wires , but most of them are the same colors (94 atx with 92 mtx) Except the DRL (canada) this was more of a pain. C100 , C101 connectors are the ones you need to look out for. This is the result BEFORE re-looming it.

i cant believe that maf dont give you problems...
usually when you clock the maf differently it makes it upset.


personally i thought the atx computer made the car feel so much better then a 3.2 running x2j

also for post # 7
i never had that problem at all... kinda makes me wonder if you got something else going on.
i was actually suprised how well the car performed also considering i just threw the egr crap away.

 

[the4biddendonut]

I'm wanting to do this swap with a 93 atx and a 91 mtx. Would the swap be a lot easier if I were to use a 93 mtx engine harness with an mtx computer? Or are there going to be problems that would make it not worth it?

 

[Shoaz]

I'm wanting to do this swap with a 93 atx and a 91 mtx. Would the swap be a lot easier if I were to use a 93 mtx engine harness with an mtx computer? Or are there going to be problems that would make it not worth it?

The easiest way is to leave the existing engine harness and computer in place, IMHO.

If you do want to swap the engine harness and computer you also need to swap oxygen sensors (with an MTX), and take care of a few other things (e.g., clutch interlock switch, etc.). It won't make much difference what year of harness you use as long as it's GenII.

 

[rubydist]

Its not the engine harness that will be the challenge, it is the front body wiring harness.

I would recommend keeping the 93 harnesses and just doing the few mods that I described above - your plan is virtually like mine where I put a 92 engine into a 95.

 

[the4biddendonut]

That makes sense, thanks a lot.

I don't want CELs and I still want to be able to pull codes if needed. Have you been able to work that out?

 

[rubydist]

Yes, I removed the cel from the dash, so I don't have to stare at it. When you want to pull codes, you do the shorting loop like normal and then you put a 12V light on the "test out" pin on the large connector (its the one down and one to the left of the one that you short) and connect the other light lead to the + side of the battery. The test light flashes just like the one on the dash, so you don't need the dash one. The only downside is that you have to pull the codes to know if the cel should be illuminated on the dash....

 

[the4biddendonut]

I'm sure I'll resurrect this thread from the dead if I ever get the project off the ground. Thanks for the info.

 

[firebat45]

Phoenix, can we get updated links to your documents on this? Both the .doc and the .pdf no longer work.

 

[rubydist]

The current link to Phoenix' conversion article is:
http://www.shospeed.com/pics/ATXtoMTX.pdf

 

[firebat45]

Thanks. I tried changing quebecspeed to shospeed for the .doc and it didn't work, so I assumed the pdf didn't either.

 

[rubydist]

bump to keep on first page of search listings for 'atx mtx swap'

 

[fast4door]

Sorry for bumping this thread but I have considered a manual swap for my 93 ATX and have found a complete 92 donor car with 45k miles. Since the donor car is complete and the miles are low i would plan on just swapping the entire subframe,engine,trans as one and of course changing the ac lines etc. would doing that make the swap a little easier?

 

[lowc]

that is all intailed in the swap as far as the motor i would use the 3.2

 

[Shoaz]

Sorry for bumping this thread but I have considered a manual swap for my 93 ATX and have found a complete 92 donor car with 45k miles. Since the donor car is complete and the miles are low i would plan on just swapping the entire subframe,engine,trans as one and of course changing the ac lines etc. would doing that make the swap a little easier?

Some things get easier that way. You'll have to do some rewiring to match the engine harness to the dash harness, as those connections differ a bit between the ATX and MTX, but that's possible and has been done before.

Depending on how much work you want to do, consider swapping blocks while you have everything out, i.e., take the 3.2 block and everything else from the 3.0, put it all together with the MTX on the MTX subframe, stick it in the chassis you want to keep. With low mileage like that, though, I don't think anyone would blame you for keeping the 3.0 intact.

 

[lowc]

ive done the rewirering thing and it was a pain in the ass its much easier to use the 3.2 harness and "trick" the ecm