7mge-7mgte Swap Computer Questions

[Emeraldage]

Hey all, the work is going decent so far on my first swap. Engine ready to be pulled out tomorrow. The only question we have right now is computers and harness...

My car which will be getting the whole engine is an 89 7mge 5spd. THe parts car is a 90 7mgte which came with a auto. The problem is the parts car was coverted to an auto we can tell as it was a crap job. It's missing brackets and bolts on the underbody and trans mount and all. You can see where the slave cylinder was pulled out and all. So anyways we're wondering if we'll have an issues here? When I get the ECU box open there were two plugs that were just hanging. I read that an auto ecu on a manual car will have an old idle when you push the clutch down. But otherwise is there anything different? Should we get a 90' 5spd ECU? Or does year matter? Were there any differences in the harness that we should be worried about? Sorry it's late and I apologize if I didn't explain this well. I also can upload a pic or two of the compartment and the ECU tag if it helps.

 

[chrisisg77]

The main difference between the A/T and M/T is idle speed management. Auto engine is also tuned different to account for keeping RPMs while shifting. A/T ecu will idle lower. You can use the A/T harness but you have to bypass the NSW.

 

[chrisisg77]

Im guessing you're going to be keeping the w58 . If so the stock clutch will last about 3 weeks at elevated boost levels. You should replace it while you have it out.

 

[Smashey]

i would stick the ecu for the 90 car in place of the 89 ge one and make sure your not in need of a yellow pre 89 ecu

 

[Emeraldage]

Not sure I really understand these responses. Yes going to keep the w58. We have a better ACT stage 3 clutch for it to hold the extra power. Going to upload a pic now of the computer's area. There was a few things unplugged so I don't know how toyota did it. If they had the auto and manual plugins on the same harness and different ones plug into diifferent computers?

So you guys are saying this ECU will be fine everything will be plug and play? Only with the idle jumping a little when I push in clutch? What do you mean bypassing NSW I've got really no idea when it comes to wiring. THe only thing I"m conerned with is backup lights if those will still work correctly.

 

[chrisisg77]

Correct.
The year 89 is a bit weird. The ECU had it own special case. I believe the plugs are grey but were really early yellow plug. I suggest buying everything the same year 89 to avoid any problems.
My bad i'm so used to looking at these diagrams. The Neutral Start Switch needs to be bypassed in order for you to use it on a manual transmission. Or else it wont turn over.
Heres what the previous owner of my car did .

he basically cut the plug off connected and looped it back in. Thats all you have to do to bypass it, loop it.
Here it is on the TEWD.
www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=038
www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=39
The Neutral start switch is connector D the first plug in the second cygnus link. You have to loop terminals 2 and 3
The circuit is closed when the shift lever is on P or Parking. So when you loop them together youre actually closing the circuit. As if your shift lever was on P.

 

[Emeraldage]

Thanks that's very helpful. Where is that A/T starter located? We're about to lift the engine.

But other than that if I use the harness and computer from the 90 car as well as the ingition assy and stuff I'll be fine? I could probably post to see if anyone wants to trade an A/t computer for M/T one.

 

[chrisisg77]

As for the back-up lights heres what you need to do lookey here

www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=078

you will use connectors A,B, and C. You
should have A and B on the harness(B is the same one you looped above)
connector C is on your transmission. You will want to run 2 wires, one from connector A pin 5
to connector C pin 1, and the other wire from connector B pin 1 to connector C pin 2. It doesn't matter which wire goes to which pin.

 

[chrisisg77]

The starter should be under the intake manifold. Youll be fine if your 89 is NOT early yellow plug and is ACTUALLY grey plug style. I dont know how to tell because i have a 88

 

[Emeraldage]

Well mine is the late 89 with the nicer bumpers and all that.

 

[Dan_Gyoba]

I'm going to second the opinion to get all the '89 wiring and ECU.

I'll also second the opinion about the stock clutch's lifespan.

 

[Emeraldage]

Dangit I'm not going to know how to do all this. From all my reading it was an easy swap. Now once I get to it I find out all these little things I haven't seen before. I'm going to have to buy a whole harness too? This is basically going to take away all the money to get a downpipe and intercooler and such. Why would I need another harness? Little small things I could try to change the wiring myself like looping that one switch.

And what are you talking about stock clutch's lifespan? I already got a new clutch for it just sitting in the garage. Just today some reason though my clutch pedal is different and it fully engages like 3" off the floor and sometimes sticks... Who knows for now.

 

[chrisisg77]

Haha dan i just said that so it will be easier on him lol you know same year everything most likely wont run into any problems. But you know people learn when the fail which is good.

And how long will the stock clutch last then and thats what i read off someone so i just said it lol.

Emerald
its easy pretty and straight forward i just did a gte swap myself and it all went well. Literally drop in. No you wont need a new harness you said yours is late 89 it will work.
Go 3" exhaust, downpipe to muffler!

dont forget the pilot bearing and to swap in the turbo cluster(;

 

[Emeraldage]

Well I'm using the harness that was iwth the 90 parts car. I don't know if that's original engin ein that car btw it runs amazing. The harness is still attached I pulled it with the harness. And thought I need to harness for GTE electronics?

What's going to happen for sure before I put it in is a 57 trim turbo rebuild from drift motion, Divorced downpipe. I want a intercooler but for the cost they don't really do all that much for low boost applications but look much nicer. Also I already have full 3" exhaust and no cat.

 

[Dan_Gyoba]

It IS an easy swap. It's about as easy as any engine swap will ever get, but you do have to pick what you swap in carefully.

I have an '89, and chose to swap in an '87 drivetrain. it went very smoothly, because the '87 drivetrain was very much compatible with my '89 chassis. Had I used a '90 donor vehicle, it wouldn't have gone nearly as well, without a lot more work. (I probably would have taken some of the chassis wiring harness from the '90 to make it work, but that only works if you have a complete parts car as a donor.)

 

[Emeraldage]

Well it's just irritating there's all these little things once you get started. Because I can't stand having things not working it bothers me. This is my first serious car work I've done, and made me realize I never ever want to be a mechanic. Lol. In one day by myself, I replaced all the shocks on my car with other ones. Had a carpel tunnel attack that night and couldn't use my arm the next day it sucked badly.

 

[peytoncoyote]

True it isn't for every one but I have been a mechanic for 6 years now and I wourk on more complex motors then the common street car. But not once I've asked for something better.

 

[Emeraldage]

Besides the part of my back always hurting, I'm working in good weather but I can't imagine when it's like 95 out. Sick of having dirty fingernails and like 50 cuts on my hands at a time haha. And worst would be having to meet a deadline. But as a home hobby to have a project car would be fun.

 

[chrisisg77]

I forgot who has that sig that says nothing is more rewarding when you see a open stretch of road and just letting loose knowing its because of you that your car drives the way it does cuts and bruises as proof. Ehh i know its completely wrong, but it goes something like that lol. But you get the idea

 

[IJ.]

Well it's just irritating there's all these little things once you get started. Because I can't stand having things not working it bothers me. This is my first serious car work I've done, and made me realize I never ever want to be a mechanic. Lol. In one day by myself, I replaced all the shocks on my car with other ones. Had a carpel tunnel attack that night and couldn't use my arm the next day it sucked badly.

Unless you're a Trust Fund Baby you picked the wrong car