1.5Slowmatic

So ive read around and searched around and i keep hearing yes and now. Can you convert an OBDII auto to OBD1? Im staying auto becasue of all the traffic i drive in dont feel like shifting. Im doing a mild turbo setup on my 97EX auto and am trying to figure out what im going to use to tune it. If i cant convert im probably going to go with an F/IC

Blown90hatcH

I have built a ton of auto to auto conversion harnesses and I will tell you from first hand experience what I have found. The OBD2 auto civic uses the ecu to control the automatic sensors on the tranny. The OBD1 auto civic uses only two of those sensors and the other changes are made via cable linkages. The OBD1 auto civic ecu will not control the remaining sensors that are on the OBD2 civic auto transmission. I have yet to have a successful OBD2-1 CIVIC automatic conversion that has worked for tuning. This is only for D-series civics that I speak of. The OBD1 automatic B16 ecu is a different story.

As far as OBD2 to OBD1 automatic Integras, preludes.....different story. I have been able to convert to OBD1 with harnesses that I have built and run an external TCU to control the auto tranny. I have been able to tune cars using Hondata and Crome with minimal issues. All of those issues are shifting relating and are consistant so that tuning is not all over the place.

My .02

1.5Slowmatic

hmmm kinda what i was expecting to hear, not what i wanted to hear though. im trying to find my best solution to tune with

dwmartin92

I attempted a similar conversion. I put an OBD1 engine and trans from a '95 Accord into a '96 Accord. It runs and drives, however, it is on an OBD2a ecu. The only code that has been thrown is the Crankshaft Position sensor. I was told that I needed to swap ecu's, however the 96 ecu has the trans built in, where the obd1 ecu's had a separate tcm. Will the jumper harness correct this issue?

Blown90hatcH

You can run the conversion harness and get the OBD1 ecu and OBD1 tcm and you will be set man. Here is the harness.

http://www.rywire.com/catalog/automa...-obd1-p-7.html

mosesayegun

what is the A10 pin on the prelude OBD1 TCM for and where would I connect it on my OBD2 conversion harness I'm building

mosesayegun

[QUOTE=Blown90hatcH;48254439]You can run the conversion harness and get the OBD1 ecu and OBD1 tcm and you will be set man. Here is the harness.

Rywire Motorsports Electronics : Home] have built my own conversion harness putting OBD1 engine and auto tranny into my 98 OBD2 prelude but not sure as to what to do with the OBD1 TCM A10 pin (yellow wire).
I know it has something to do with the D4 light on the dash but need to know where to connect it to on OBD2.

Nelson Serpas

hey whats up im trying to the a similar thing but the car is already 5 speed how did you wire up the distributor? thats where me and my friend are stuck on did you use the external coil? or the obd1 distributor?

mosesayegun

I used my 5th gen engine wiring harness so just put my obd2 distributor on.
no need for me to rewire.

mosesayegun

internal coil

mosesayegun

does anyone know what the difference is between P13 N50 and P13 N51 ecu.
I know they are both from 93 JDM prelude auto.
can anyone help.