using Japanese ECU in US spec car

Dpine · Post by **Dpine** » Sat Nov 13, 2021 8:37 pm

What are the requirements for using a Japanese market ITR ECU (00 year in 00 US car) for the US ITR? They are cheap on Ebay vs A chipped obd1 ECU with adapter harness.
This is hypothetical based on if one had to replace the factory ECU and the OEM US part wasn't available.

aklackner · Post by **aklackner** » Sun Nov 14, 2021 9:35 am

From what I remember, I think you’ll need a jumper harness, and probably won’t run optimally.

The JDM motor has higher compression and I believe expects higher octane. Without the ability to reprogram the tune, it will probably run ok but probably not as well as a US p73.

You may also have issues with the evap system. Not sure if the JDM unit will control either the can vent sol. or the evap sol.

I know 00-01 have an issue with the obd1 and not having a tach signal from the distributor, not sure if JDM units would need the same workaround to get tach back at the cluster.

If you do run an obd1 ecu have it tuned, do not run a generic baseline map supplied on a “chip” for any length of time. It really is necessary to get a proper tune for motor longevity.

Post by **coolhandluke** » Sun Nov 14, 2021 10:36 am

If tracking, the speed limitation in a JDM ECU is a factor. If the ECU and and chassis are matching ODBIIx, I don't see the need for a jumper harness, ie ODBIIb ECU from a 99+ chassis for your 00-01' chassis.

I can't speak for EVAP, but I hope others with first hand experience chime in, as I agree that is a valid concern (re: CEL.)

If emissions isn't an requirement, I like the idea of an ODBI ECU + Hondata.

I'm particular on tunes. I've had both poor experiences with off the shelf "base maps" and tunes that were subpar. Nothing is worse than a car with idle issues, jumpy acceleration, or bogging at WOT shifts on track. We have Hondata as a Type R Expo sponsor and Innovative Motorworks (IMW) is a very experienced Honda/more tuner for golden era and newer FK8 Civic Type R's.

Stin1 · Post by **Stin1** » Sun Nov 14, 2021 10:46 am

It won’t communicate if you require emissions. The feel exactly the same in personal opinion. My car has a high idle with all accessories turned on , ac fog lights using the Usdm ecu . It doesn’t do that with the jdm ecu . That is the only thing I noticed and I am not going fast enough to notice the speed governor .

touringteg · Post by **touringteg** » Sun Nov 14, 2021 11:57 am

I tried a 95-97 JDM ITR ecu and jumper harness on my 2001 CDM ITR. I found it didn't idle smooth and I couldn't bring the the idle down from 1100rpm. It drove ok but the idle bothered me. No check engine or other warning lights.

I ended up selling the ECU and harness. I tried it because I had a CEL for evap issues on my original 2001 ITR. One of the capacitors leaked/failed.

Dpine · Post by **Dpine** » Sun Nov 14, 2021 1:05 pm

Based on responses I think if I had to Id go one way the other a chipped obd1 ecu (Neptune probably) would be the way to go since that's what I have used in the past on other cars and they are still readily available. I have access to a really good tuner in Richmond if I had to.
I think I would almost do this now and pack away the OEM ecu so that I don't have to worry about it failing and finding another.
If the car isn't going to run like factory with the JDM ecu then the best bet would be something tunable.
I'm mostly stock except for my hitech header and CT Ice Box. Id imagine there is some HP to be made on a tune even with minor bolt ons.

Stin1 · Post by **Stin1** » Sun Nov 14, 2021 3:01 pm

touringteg wrote: ↑Sun Nov 14, 2021 11:57 am I tried a 95-97 JDM ITR ecu and jumper harness on my 2001 CDM ITR. I found it didn't idle smooth and I couldn't bring the the idle down from 1100rpm. It drove ok but the idle bothered me. No check engine or other warning lights.

I ended up selling the ECU and harness. I tried it because I had a CEL for evap issues on my original 2001 ITR. One of the capacitors leaked/failed.

The Canadian ecu excludes an eld which will result in a high idle using other countries.

Post by **jayhaire** » Sun Nov 14, 2021 4:12 pm

We had used JDM ECUs a lot in the past without much issue, but today, I haven't had good luck with the 97R. However, it could be another issue. It won't idle well at all and stalls for me. The ECU might be bad and will pull the JDM ECU from the DB8R someday to compare.
In the DB8R, I did find the soft speed limiter on track a couple of times.
In both cars, I prefer to use a P72 OBD1 with Hondata.

AndyD · Post by **AndyD** » Sun Nov 14, 2021 6:21 pm

If you use the JDM 2000 ECU you will have the speed limiter, no security immobilizer, and no emissions support.

More than likely the emissions support could be an issue. If so, the JDM ECU won't fit your needs. But the JDM ECU can at least be used temporarily of needed. No modifications needed to work with your setup.

Post by **coolhandluke** » Sun Nov 14, 2021 6:42 pm

Dpine wrote:Based on responses I think if I had to Id go one way the other a chipped obd1 ecu (Neptune probably) would be the way to go since that's what I have used in the past on other cars and they are still readily available. I have access to a really good tuner in Richmond if I had to.
I think I would almost do this now and pack away the OEM ecu so that I don't have to worry about it failing and finding another.
If the car isn't going to run like factory with the JDM ecu then the best bet would be something tunable.
I'm mostly stock except for my hitech header and CT Ice Box. Id imagine there is some HP to be made on a tune even with minor bolt ons.

What leads you to Neptune?

Type R Club of America