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Ok I need help. I am swaping a 94 mx3 i am putting a 91 escort gt motor in it. But i was told i have to change some of the wires on my harness to make it run with the bp ecu. I have been searching on here about a week now and cant find anyone that talks about what wires they are. So if anyone can help out show me a pic of the wire i need to change that would be great. And i am swap over the whole engine harness from the egt as well.

If its a 94' then you will need the wire harness from the ECU to the engine bay from either a 92-93 mx3 or protege, 323, its all one piece. you will also need the VAF instead of the MAF the 94' has. also you will need the external coil relay. that should be about all the wiring things you will need if you already have the ECU.

Hope that helps some

EDIT: you will also need a MAZDA valve cover

That does help how about the harness from the escort gt i have a whole car with all the stuff i need to swap it over.

I made this for the wiring when I did my swap

Now i could be wrong, someone correct me if I am. but from what i remember is that Ford used its own wiring system. so I am unsure of the compatibility of the two. If you have a complete car then i would try it. Do the plugs on the ECU's look similar?

you might want to search club protege forum as well LOTS of info there.

Ok just so i got this down i only have to swap out those two wires and the motor will work fine in the car. Right Mi|<E. And from what i see just to make sure i am right we are swaping the wire from the fuse box under the hood to make it work right. And i dont see y the escort gt harness wont work its the same motor pretty just a drifferent body. But it would be great Mi|<E if u could let me know if i am right i am not all that great with wiring and i want to get this car going good.

Fuse box? No no those are the black and white plug ends that connect
near the ECU

hey mazda guy its pretty simple with the wiring splicing, at first i thought it was rocket science lol but just connect the black and yellow wire from the escort gt harness to the black and white wire thats already on the mx3. My swap is from a 95 escort gt to a 95 mx3. It took me about 5 hours to do the whole swap thanks to Mikes worklog, which i suggest you study first. Follow the wiring schematic he showed you and your new bp engine will start right up when your finished.


The only thing Mike is that I never got my rear window defrost to work and charging sytem light has been on for about half a year now any suggestions???

Ok guys that u for the update i am going to start my swap over on saturday. I will keep u guys update on how it goes if i need anymore help as well.

Nlp303 is that the only wire u swaped and the car ran fine or did u have to swap more to make it work.

It actually ran without the wire swap but it ran crappy. but yea its just that one wire. its hard to get to but its easy. The wires are located right under the ECU behind where the stereo goes. Just remember the B/Y needs to be connected to the B/white wire. I just taped em together and it worked fine but a good soldering job will be better.

Your lucky like me that you have a complete escort gt donor car. everry thing drops right in to the mazda from the escort.

Another tip is that if your using escort gt tranny mounts your shifter linkages to the tranny will not connect because their is a bolt on the tranny mount that is in the way but its not a big deal just cut about half an inch off the bolt. I used a sawzall.

Last one is that the fuel line return hose will be different on both cars. I just bought 4 feet of fuel hose and customized my own. you only need about 2 ft but youll see for yourself when your at that point.

Like I said this swap can be done in one day. If both cars ran correctly before the swap their is absolutely no reason why you cant cruise your new MX3 BP after your done. so goodluck mazdaguy.

Ok thanks NLP303 now one more question doesn't everything work right in your car like cool fan and like turn signals and stuff I know your rear defrost doesn't but that's no big deal this is going to be my turbo summer car. But want everything to work when I drive it.

Yeah everything works, its weird to me how the escort computer knows what to do with all the mazda lights and cooling fans and all other accesories lol. but its just plug and play with this swap. just the dam defrost is giving me trouble.

oh and the escort gt only has one fan and the mx3 has 2 fans but one of them is for when you have the AC on full blast in the summer. if your turboing your bp then your probably going to remove the AC anyways. But yeah the left hand side fan on my mx3 works great and my bp never overheats not even on 4 hour drives. I heard it gives cars like 5 HP when the ac is removed.

One more thing I WOULD replace the thermostat on the bp ASAP its only 5 bucks. I ran my car 2 weeks and my water pump broke I later seen that the stupid thermostat was busted causing my water pump failure.

Just because its an escort versus a mazda, its the exact same PCM, designed for the same harness/engine. Mazda built it for Ford.

For the defrost, look under the dash at the relays, you'll see one that is burnt around the plug... replace it and its pigtail/clip with a 30A relay and you should be fine.

The second fan is for A/C and runs exactly with the compressor.

removing A/C does not gain you any horsepower. Just don't have your A/C on when you're racing, then its an idler.

broken thermostat won't cause W/P failure, just overheat or overcool. Not sure where you got that idea.

Yeah your right an escort gt is pretty much a mazda protege LX with a different body.

Im thinking if you remove your AC compressor and power steering thats a big strain taken off the crankshaft. thats two less pullys it has to move... Maybe thats like 1/2 a hp gain I really dont know, All that matters is that the crankshaft is happier thats for sure. And in my opinion the engine bay looks way sweeter with no P/S fluid reservoir and less AC crap that I dont even use.

Im pretty sure its not that relay because the day before my swap the defrost was working and now not even the led on the defrost button turns on, its probably the wiring or something. I have the black and blue wire connected to the yellow wire. Isnt that what mike says in his wiring diagram?

You know what would help, an online ford escort gt manual like the one we have for our mx3. I could just buy a hard copy but im really really broke right now lol. If anyone knows of an online manual please let me know.

And sorry mazda guy for misleading you, first find out if your thermostat works if it doesnt replace it lol there you go Ryan.