converting from 86 computer to 89

[cmason07]

First of all, I just joined and am happy to be a part of the group!

I race an 86 RX7 in Houston with an 89 motor. I just got my hands on an ECU from an 89 vert. I have the engine harness from the pass. side, the injectors, and the AFM.

Do I need any more harnesses? ...the under dash one?

Also, I don't have an electronic oil metering pump and I am told by Mazda Comp that I either need to get one or there is some trick to putting some resistor in the circuit to get around having to have one. Anyone got any ideas?

Any experiences you wish to share would be greatly appreciated and needed.

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Colin Mason
Houston, TX
ITS RX-7 #07

[C. Ludwig]

You'll need the harness that runs under the dash and connects to the ignition coils. Don't do like I did and spend two days looking for the CAS connection on that harness! It was moved to the emissions harness on the passenger side. You will need the OMP. There's probably a trick to make the ECU think it's there but I have never seen it mentioned. Without the OMP the ECU goes into limp mode. I spent a couple weeks figuring that one out! OK, I'm not much for asking for help. Think that's it. The atmospheric pressure sensor was re-located inside the ECU on the later cars so don't spend too much time looking for that either. I actually figured that one out pretty quickly.

Chris

[Silkworm]

See, my 88 has the CAS plug on the pass side harness. So I don't know when the CAS plug was moved.. Anyway, you'll need the 89 throttle body with TPS and 89 OMP if you don't already, but other than that, I think you're set.

PaulC


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[cmason07]

I do not have the 89 throttle body. My TPS is still the 86 and it just hangs there. It isn't hooked up at all to the mechanicals. If I remove it from the wiring harness, bad things happen, but if I just unbolt it and let hang, then the car is happy. I hope I can get away with the same stuff with the 89 ECU.

Surely, there is a way to bypass the OMP.

[Silkworm]

- I don't think the 89 ECU will be happy without both TPS's working, others can say for sure

- If you find a way, you be sure to let us know Ask Chris Ludwig about how irritating it is to try and get your engine running without the OMP hooked up with the 89-91 ECU.

PaulC

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[C. Ludwig]

Originally posted by Silkworm:
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- If you find a way, you be sure to let us know Ask Chris Ludwig about how irritating it is to try and get your engine running without the OMP hooked up with the 89-91 ECU.

PaulC

UUUGGGGGHHHH!!!!

Chris