OK here's the deal. I recently ran across a clean 2000 Civic EX for a price I couldnt pass up. Now that I have the car i have learned some stuff about it such as,,,, it's a 2000 with a '95 D16Z6 engine. Not sure if the tranny was swapped (has a 5 speed MT) but i'm pretty sure neither the ECU or wiring harness were swapped. The problem I am having is an idling issue.

When I start the car it hits around 1.5 to 2k RPM with no load and then will drop to 750 to 1k. When i drive down the road and come to a stop it will hang around 2.5k RPM for several seconds (5 to 15) and then drop back down to around 1k or less.

I am guessing this is not normal for the car and not sure where to start to try and fix the issue.

Is the 2000 ECU for the D16Y8 compatible with the D16Z6 and would resetting the ECU possibly help the issue. Im gonna clean the FITV and see if that helps. Not gonna mess with the IAC for now as the engine temp doesnt seem to be an affecting issue. It does the same thing hot or cold.

Anyways I would really appreciate any advice offered as I am new to the Honda World. Thanks In Advance

Ps: the engine runs very smooth, no missing or hesitation, just the slow idle drop down.

 

What ECU is in the car?

 

To the best of my knowledge it is the factory ECU for the D16Y8 engine.
So it should be the P2P.

 

Might want to check to be sure. I thouhgt the P28 was supposed to be the ECU for that engine.

 

D16z6, is that OBD1?

Those symptoms sound textbook for EACV (also known as IACV on some engines). Also, check the TPS voltage (if present) and make sure the throttle cable is not too tight.

 

yeah the P28 is the ecu for the 95 engine but previous owner blew up D16Y8 and stuck the D16Z6 in the 2000 Civic which should have had the P2P from the factory and I am guessing the P28 wasnt added when the engine was installed. I would be willing to bet the factory ECU (P2P) wasn't swapped for the P28.

P28 is OBD1,,,, P2P is OBD2.