[Dsmith1484]

SCCA will allow us to do anything we want to the internals of the ecu. The housing and the stock wiring harness must remain unchanged. We are not allowed to add any wires or sensors that are used by the ecu. Basically what SCCA is saying is that you can chip your car.

The problem is that I can not find anyone that can chip / reprogram the early ecu's everyone seems to only be able to work with the 88 and up. So I was thinking. Could I get my SCCA IT car to run on an 88 ECU? I would just have to get it to fit in to the 85 ECU housing and make up some sort of jumper cable / ribbon cable inside the housing that would adapt the 88 ecu to the 85 wiring. I have been looking at the wiring diagrams for the two and it looks like it may be do able.

I am wondering has anyone done this? I am also looking for an ECU from and 88 with a "ge" motor.

I am also looking for a good clear wiring diagram for the 88 ecu. I have the one off this side but it is a bit blurry and hard to read. (Ya I am over 40 and the eyes are not what they once were) If anyone had a clear copy or could scan there manual and send me one I would appreciate It. I have the 85 factory shop manual so I have the wiring for the 85 ecu.

My plan would be to see if I could get the 88 ecu to work with the 85 car then I can get the 88 ecu reprogrammed / re flashed / chipped. I have been told that it is good for 10 hp on cars with free flowing intake and exhaust. Who knows if I get this to work we may be able to keep up with the Honda's

 

[ITA-MR2]

You can update / backdate complete assemblies from the same spec line in the GCR. '85-'89 are all on the same spec line. An ECU is considered an assembly. Therefore you may legally put an '88 ECU in an '85, and you don't have to change the case.

 

[Dsmith1484]

So I would then only need to get the 88 ecu and the 88 wiring harness. Since I have the harness virtually out of the car at the moment (motor rebuild in progress) now would be the time to try this. I need to find an 88 parts car

 

[Dsmith1484]

I have been working on this problem for a while now and this is where we are.

I have acquired ECUs from

85MR2 - Canadian Car not sure if it is a JDM ECU or American.
86MR2 - Our parts car that we stripped to a shell (still have wiring harness)
89MR2 -
89Celiac Twin cam

I have always been told that the 88 and 89 computers are different than the ones up to 87.

Things of note that 85 computer is significantly smaller. Other than that the 86 and the 89 MR2 computers appear to be the exact same with slight differences in the numbers on the chips. The pin outs in the three MR2 units appear to be the same. I was comparing the three and visual inspection did not find any labeling differences on the boards. I will document the three and see for sure.


Here is a photo of the four units together

here are the four labels up close

The end game here is to figure out how these things work and see it there is a way to make them programmable. I am going to see If JET can work with the 89 ECU (as they told me they could a while back)

I would also like to See if there is a way to access the maps and change them. I read somewhere that you can adapt a daughter card to the ecu but there was not much more to it than that. Can anyone steer me to more information about these ECU's. Since these appear to be made by Nippondenso may be they could help.

The other option that I see to get control of the ecu us to put a mega-squirt unit in the ecu housing and adapting it to the wiring harness in side the housing of the ecu. I have seen a writeup of this except they made an adaptor cable from the mega-squirt to the stock harness using the plugs from a junkyard ECU. They also ran a vacuum line from the ECU to the intake so the MAP sensor on the mega-squirt will work. I would then run the mega-squirt using Alpha-N because the mega-squirt can not use the AFM and adding a MAP and the associated vacuum line is against the rules of ITA. Anyone got any ideas?

Other things planed

The AFM trick - again. Old AFM got wet and rusted.
Put a "pot" in the temp sensor circuit to be able to rich-en it up manually if needed.
wide-band o2 for tuning. I am not sure that I can legally change from the stock O2 to a Wide-band. I could however use the stock one for the ECU and the wide-band for tuning and making the maps and run the stock one while racing once the maps are set up.

Ok Now that I have babbled on anyone else got any ideas or information on the stock ECU. I have an electrical engineer working for me may be I will let him have a go at deciphering the code or see if he knows how to reprogram a stock ECU.

 

[Papo J]

I've heard that El Prototypes can modify the maps and re-program those.