Deco
Thanks Rob. Ill give it a look. What i dont understand is that the NA ECU didnt have an ABS wire. So in theory nothing has changed by not having it hooked up to this ECU.

Ah yeah my bad. What I said is probably not relevant then, unless there was another wire from the ECU to the ABS (but not labelled as an ABS wire).
Have a look at the BGB anyway, try to find where the signal to the ABS light on the dash comes from.

Did you check the ABS fuse?

robk
Did you check the ABS fuse?

Sure did and its all fine. I also check for codes and its just producing a solid ABS light which means there is a malfunction at the ECU which i find very hard to believe. I might try running this wire to the ECU and see if it makes a difference. 

jessyeo
hey,
if you dont mind me asking, how much is the swap costing?
i also have a na mr2
cheers.

The final cost is dependent on the condition of the half cut and whether or not you can do the work yourself and where you can get it from. I know when i did a rebuilt NA motor; toyota quoted me 2k in labour for the engine drop/replace. So far for the halfcut it self was 4.2k delivered from WA. Then in parts which has included a rebuilt turbo, boost controller etc has equaled 2.4k. Since then i have stopped counting but im around the 7k point at the moment. I still have a tune up and blue slip/change of details bill to come yet. 
 
Im sure it can be done for a lot less but that is assuming the halfcut is pretty much in A1 condition or really you could just sell up and buy a good condition MR2 Turbo for the same price. Though the reason I stuck with my MR2 is because i know where mine is mechanically and i didnt want to buy into more problems. 

I just found this for you.
http://stephenmason.com/cars/mr2abscode.html
 
It's a how to guide for pulling the ABS fault codes and what they mean. Should get you out of trouble.

I was at MRC for most of today, while they worked on my car.
I also saw yours while I was there:

 
As Mark told you on the phone, I think your car made something like 153rwkw at 11.5psi, which is almost exactly what it should be making :-) I heard him talking about the boost control issues though.
Mark told me about the problem with the rear ABS ring which explained the ABS issues hahaha.

That 153RWKW at stock boost is pretty good man. You should be up around 190-200 at 17psi with your tuned ecu.
 
Another thing, I think that lean spot just as you come onto boost is a gen 3 ecu trait. They all do it from the factory.
Have a search on MR2OC about it?

If it helps I have a stock gen 3 ecu here that I borrowed off Darius on the forum to see if my own gen3 ecu had any problems. Maybe send him a PM and see if you can borrow it to try it out?