B16A ECU Problem

Inseino

Junior Member
I picked up a 90 CRX Si with a B16A2 swap. The main problem here is that I don't know the whole history of the car. Everything looks alright, but I've been having problems setting up the timing. Me and my buddy switched the timing belt, but we can't seem to jump the service connector to set the timing. I noticed the the car's got a B16A PR3 ECU. Now is it even possible for a B16A2 to run properly with such an old ECU? And if so, is it possible the wiring wasn't hooked up correctly? Please help me out. Thanks!
 

Inseino

Junior Member
Yeah, it should be OBD2, but in this case its OBD1. I started ripping up the wire harness just to check it out, and it looks like the harness is the stock harness that came with the CRX. I went to look at some wiring diagrams and I noticed that there is a lot more stuff cross connected with the service connector in the 99 Civic than in the 90 CRX. So my question now is, can the OBD1 PR3 really work properly with this engine? And if so, then back to my main question, how the hell do I setup up the timing on this car? We tried it again, and it seems to do the job for the first hour or so of driving, and then it goes all out of whack again. And I'm positive the tension and everything on the belt is perfect.
 

posol

RETIRED
Staff member
pr3 is NOT obd1. it is obd0.

it is the first gen b16a ecu. it will run any b16 just fine.
BUT, your electronics on the motor need to match.

you will need an obd0 distributor, peak/hold injectors w/resistor box, obd0 VSS to match the obd0 ecu. obd1/2 parts use a different pulse width
 

Inseino

Junior Member
Oooooooohh, now that makes sense. Well, I want it to be OBD1. So could I get any OBD1 ECU and just connect it using an OBD0 to OBD1 conversion harness?
 

posol

RETIRED
Staff member
yup- pick up a p30 or p28 if you plan to chip it, with the 0->1 conversion harness, and keep your obd1 electronics.

VSS? speed sensor? or what is it? cant i use the obd0 on a obd1 ecu?


yes, vss = vehicle speed sensor on the tranny.
no, you can't use obd0 on oa obd1 ecu... they transmit a different pulse width.

basically, its a rod that spins for every revloution of the tranny. each rotation it spends out a voltage to the computer. the obd1/2 voltage is different than the obd0 voltage. thus, they don't match each other and shit gets wack.
 

Inseino

Junior Member
I guess I'd better go with a P28. From what I was reading, the P28 and P72 are the best ones to use with Uberdata. Also, how do I go about checking if my distributor is OBD1 or 2? Also, what are peak/hold injectors w/resistor box? And I also read that I need an O2 sensor with 4 wires coming out of it instead of just 1? I just want to double check all this so I can get everything I need asap.
 

^crx^

Senior Member
wow. so could the vss make my car go crazy at a given rpm? or would it just give a false mph?
 
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