Daniel Hong

Hello,
Recently I have decided to finally replace the D16Y7 in my year 2000 ek hatch (OBD2B) with a B18B1 from a 1998 Integra (OBD2A).
I've done most of the wiring but a problem I can't seem to overcome is the IACV wiring. I have already done the 3-pin to 2-pin conversion on the plug side but
can't for the life of me find out how to repin on the ecu side. Katman's guide shows what seems to be the pin swap for switching to OBD1.
I am currently using a OBD2B to OBD2A adapter harness.
The car does run but when I used my OBD scanner to check, the code P1508 appears which is a IACV Circuit Malfunction.
To keep it idling at around 800 RPM I had to manually adjust the idler screw all the way open. Clearly this is not how it's supposed to be.


Another question that I have been wondering about is where I would connect the IAT sensor. The civic harness has a 3 pin plug while the integra is a 2 pin. Which wires to I connect to get that working?


Thanks,

mk378

Find a schematic of the OBDIIa car and see which pin goes to the IACV.

OBDII Civic has a 2 wire IAT with a square plug, mounted on the rubber intake pipe instead of the manifold. You will need to extend wires and change the plug. The 3 wire plug you are looking at must be something else, there is no such thing as a 3 wire IAT.

JRCivic1

OP, you have inadvertently used an OBD-2A wiring diagram to wire a OBD-2B engine harness... that is the wrong "Katman" information. If you moved a wire at A14 to A12 in your OBD-2B engine harness... move it back (and re install the wire you removed at A13 if you did so). If you moved it in the ECU side of your adapter harness (OBD-2A plug "A"), you will need to follow the wire you have moved to A12 back to the other end of the adapter harness. It should terminate at either B6 or B23 on the OBD-2B side. The 2-wire IACV black/blue wire belongs in the B23 location, so you may have to move that wire as well. The orange wire that needs to be removed is at B16 in the OBD-2B plug. In the end, the pathway for continuity between the black/blue wire at the IACV plug = IACV -> B23 (OBD-2B) -> A12 (OBD-2A)... and obviously make sure you have 12v+ on the yellow/black wire at the IACV with the key on.

As for your IAT sensor... ALL of them are two wire sensors, so you must be confused as to which plug should be used. The Integra IAT sensor has a round grey plug whereas the '96-00 Civic IAT sensor has a square black plug... both have two wires in them and the wire colors are red/yellow and green/white (or green/black). You will simply swap the plug style from black to grey and lengthen the wires to reach the IAT sensor mounted on the intake manifold instead of the air inlet tube.

dwellz80