i got a 91 civic si with a B18b engine. i just found out that i have been running my stock PM6 ecu with the ls engine for 2 years. ever since i had the swap i've had this weird o2 problem, so what ecu's do you run a b18a/b in a 88-91 civic? also how do you tell the diffrance between the obd0 pr4 and the obd1 pr4? thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S13 slide &raquo;</TD></TR><TR><TD CLASS="quote"> i got a 91 civic si with a B18b engine. i just found out that i have been running my stock PM6 ecu with the ls engine for 2 years. ever since i had the swap i've had this weird o2 problem, so what ecu's do you run a b18a/b in a 88-91 civic? also how do you tell the diffrance between the obd0 pr4 and the obd1 pr4? thanks</TD></TR></TABLE>

The easiest is to use a 90-91 Integra OBD0 PR4 ECU. The difference between the 90-91 OBD0 PR4 and the 92-93 OBD1 PR4 is the plug styles. The OBD0 will look exactly like the connectors on your PM6 but the OBD1 will have the gray connectors, same as the 92-95 Civic's.

 

now how would the PM6 ecu even run the Ls? i have bogging, surging problems, havent been able to keep a stable idle for the past 3 years also. and after driving a bit my cel comes on, but then i turn the key off it goes away for a while. the ecu just flashes code one. these would be symptoms of running the pm6 ecu correct? thanks

 

The PM6 will run the motor because it controls the same setup of sensors and the pinouts are the same as the 90-91 PR4. I would say that the reason you are throwing a code 1 is that the car is running very lean and it's fouling the O2 sensor. My friend had the same problem doing a DPFI to MPFI and trying to use OBD2 injectors. It could also just be a bad O2 or the wiring also. Either way you need to get a PR4 OBD0 ECU and check the O2 problem after that.
I have a 91 CRX DX with a 96 B18B1 and I'm using the OBD0 PR4 ECU, distributor, and injectors with DPFI converted to MPFI. I have ran the car that way since the swap about 2 years ago and I haven't had any problems.