b18c swap high idle

[silvermitsu10]

I just acquired a 1992 civic hatch with a b18c swapped in. It is using a p28 ecu that looks stock to me, although the previous owner said that the car had been tuned. It is idling around 2000 rpm. I'm new to hondas, but not new to the auto world in general, and I'm looking for a few suggestions on where to start looking for the high idle problem. Thanks for any advice.

 

[Briansol]

p28 is most likely chipped. Short of writing a new rom for it that can control idle rpm, you may be able to adjust it doen a bit with the IACV screw on the TB.
also, it coul dbe running the wrong throttle cable. if using the gsr manifold, it may have the wrong throttle cable which pulls on it a bit to keep it open more than it should be. It may also just need the cable physically adjusted.

 

[silvermitsu10]

I'll check the cables this evening and play around with the IACV a bit as well. There is a small bug on the intake tubing that has nothing in it, and a plug that is hanging very close there, it there supposed to be an IAT sensor or a MAP sensor that goes there? Thanks for the quick reply. I appreciate the help.

 

[Briansol]

you'll have to take a pic of it.
map should have its own vac line on the top of the TB. IAT doens't have a vac source IRRC.