Rev 2 3sgte swap, wiring help needed

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James159
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Rev 2 3sgte swap, wiring help needed

Post by James159 »

Hi, sorry if this has been covered before, I have been researching but cannot find a clear answer to my particular situation. I have a rev 2 turbo mr2 that I'm planning to swap into my rev 4 n/a, using the turbo engine harness and ecu. Now my question is to do with the body harness. Can I keep the rev 4 body harness in the car and repin it to work on the rev 2 turbo ecu? Or will I need to pull it all out and use the body harness from the rev 2?
Basically, which route would be easiest?
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Ryan S
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Re: Rev 2 3sgte swap, wiring help needed

Post by Ryan S »

Just swap engine harness and it will work fine.
James159
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Re: Rev 2 3sgte swap, wiring help needed

Post by James159 »

But aren't the rev 2 and rev 4 body harness pins different at the ecu connector? Surely just plugging thr rev 4 body harness into the rev 2 ecu wouldn't work??
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Re: Rev 2 3sgte swap, wiring help needed

Post by Ryan S »

James159 wrote:But aren't the rev 2 and rev 4 body harness pins different at the ecu connector? Surely just plugging thr rev 4 body harness into the rev 2 ecu wouldn't work??


I've seen this swap done and all that was required was changing the engine loom. You unplug from in the cabin and replace the loom from there back. Admittedly I didn't see the connectors but my friend who did it (scuba ellis on mr2oc) said it was just a case of swapping the harness over. He mentioned no cutting etc.
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Re: Rev 2 3sgte swap, wiring help needed

Post by James159 »

Ahh, I get you. So just use the rev 2 wiring from the cabin back. Is that just the connection down at the kick panel? Or are there other connections in the cabin I need to get to, such as anything behind the dash or center console? Thanks for the info btw!
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Re: Rev 2 3sgte swap, wiring help needed

Post by Ryan S »

James159 wrote:Ahh, I get you. So just use the rev 2 wiring from the cabin back. Is that just the connection down at the kick panel? Or are there other connections in the cabin I need to get to, such as anything behind the dash or center console? Thanks for the info btw!


It's been a long time from I've rooted around in there but I think it's from the passenger footwell. It's deffo the passenger side seat area, Either footwell or behind the seat somewhere. But yeah your turbo loom should plug straight in.
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Re: Rev 2 3sgte swap, wiring help needed

Post by Ryan S »

also, if you're going to have to do all that wioring, Put the engine bay fuse box in the boot for a much cleaner look. Check out JimGTS' posts on wire tuck. Very clean looking. I pulled mine out and run it behind the space where the strut is into the boot (no pics as it isn't complete yet)
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Re: Rev 2 3sgte swap, wiring help needed

Post by James159 »

That's a great idea, I'll have a look at that post! If it's that easy then I'll definitely be going down that route! Thanks a lot!
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Re: Rev 2 3sgte swap, wiring help needed

Post by Ryan S »

James159 wrote:That's a great idea, I'll have a look at that post! If it's that easy then I'll definitely be going down that route! Thanks a lot!


It's an easy mod if you're fitting another loom anyway. Keeps the fusebox protected a bit more from the elements too. I had issues with mine and had to trace a short in it. The cars are getting on now so every little helps!
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Re: Rev 2 3sgte swap, wiring help needed

Post by pbmr2 »

agreed, use the rev2 loom from the ecu all the way to the front passenger footwell. I have a feeling there is still the odd pin you have to swap at the front there.
It's way easier than trying to do anything with the rev4 loom, just use the rev2 loom.

will try to find an old swap how-to for you.
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toxo
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Re: Rev 2 3sgte swap, wiring help needed

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Speed signals will be pins to watch out for.
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Re: Rev 2 3sgte swap, wiring help needed

Post by PW@Woodsport »

I actually find it much easier not changing the kickwell loom and just repin the engine harness at the rear to run properly in the car, that way there are no chassis related faults to chase afterwards (of which there can be many)

I've converted dozens to turbo and never changed a kickwell harness yet, I prefer to keep the cars chassis loom correct to the vehicle, others may disagree.
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toxo
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Re: Rev 2 3sgte swap, wiring help needed

Post by toxo »

I'm with you on that one. I've not done many but the changes I've made have all either happened in the fusebox or at the ECU
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Re: Rev 2 3sgte swap, wiring help needed

Post by PW@Woodsport »

I just don't get the whole "change the kickwell loom" thing, even other specialists do that, sure if it comes from exactly the same revision/month and you're lucky enough everything works afterwards then I suppose it's ok, but the number of people that ring or email me with kickwell change issues is scary..... I guess people just want the engine to run and worry about the other issues later.

It's never taken me more than 2 or 3 pins to move at the rear to get it all working properly and within 10 minutes or so, it takes a lot of effort to swap that kickwell loom out.


Each to their own I suppose.
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PW@Woodsport
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Re: Rev 2 3sgte swap, wiring help needed

Post by PW@Woodsport »

I just don't get the whole "change the kickwell loom" thing, even other specialists do that, sure if it comes from exactly the same revision/month and you're lucky enough everything works afterwards then I suppose it's ok, but the number of people that ring or email me with kickwell change issues is scary..... I guess people just want the engine to run and worry about the other issues later.

It's never taken me more than 2 or 3 pins to move at the rear to get it all working properly and within 10 minutes or so, it takes a lot of effort to swap that kickwell loom out.


Each to their own I suppose.
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SonicSW20
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Re: Rev 2 3sgte swap, wiring help needed

Post by SonicSW20 »

PW@Woodsport wrote:I actually find it much easier not changing the kickwell loom and just repin the engine harness at the rear to run properly in the car, that way there are no chassis related faults to chase afterwards (of which there can be many)

I've converted dozens to turbo and never changed a kickwell harness yet, I prefer to keep the cars chassis loom correct to the vehicle, others may disagree.


Exactly what I did for my Rev5/Gen3 conversion. Wasn't even that many pins to swap and the Toyota ECU connectors are pretty easy to work with. I wrote it all down somewhere with the intention of putting a pin swap guide on here and MR2OC, haven't got round to it yet!

If you swap the whole body loom you're going to have to do some pin swaps anyway.
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toxo
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Re: Rev 2 3sgte swap, wiring help needed

Post by toxo »

I did a very late GE engine into a very old FE shell recently, that was fairly entertaining. Funny how much of the wiring Toyota realised they got wrong early on and revised!
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