1999 civic original engine d16y8 vtec american version. reoplacement engine d15b vtec jap version.

Engine runs fine but the idle is about 1600 rpm. Any ideas of what the problem is?
Thanks
KMD

 

...KMD posted for me originally, but got my registration up and running...thanks KMD!

Additional info:
-engine idle cycles from about 1500 to 1700 @ about 1 Hz
-Check Engine light on with NOK sensor listed as root cause

I've read various similar forums/threads suggesting I need an "OBD1 P08 ECU", and/or an "obd2a to obd1 ecu wiring harness conversion", but I when I bought this engine from "Tigerautoparts.com" there was never any mention of having to change the ECU or what year and/or type (obd1 vs 2) ecu that it was made with originally.

Any help would be greatly appreciated!

 

Did you change just the engine itself (block and head)? That's what should have been done; keep all of your USDM EX's manifolds and controls.

Unplug the IACV and see if idle speed drops. If not, high out of control idling on these MAP controlled engines is caused by excessive air getting into the intake manifold somehow. I think the small injector air holes found on OBDIIb intake manifolds could be the problem. If there aren't corresponding ports in the JDM head, you'll need to weld up the holes in the manifold.

 

Thanks MK378,

It was an entire engine swap with tranny (both original and swap-out with 5 sp manual), i.e., all manifolds/controls were swapped as well. I'll try unplugging the IACV tonight. Manifold/Head came together, so I'm thinking there are no mismatched holes.

I did not personally swap the engine out...had a local (reputable) auto shop do it, so I'll have to talk with them about it.

With continued research, it's sounding more and more like I need a new (P2J) ECU, which as I understand is hard to come by for a manual tranny?!?!