Recently swapped a B16 into my wagon. Guy who owned the engine before had a bad mechanic work on it, and the swap had some butchered wiring/broken sensors/mechanical issues. Anyways, it's all fixed and running good. Pulls good, no CEL other then passive code 20 (I hear it's a ground sensor?). VTEC works great.

Engine idles at 1500rpm, regardless of idle screw adjustment. If I bring it lower then 1500 rpm with idle screw it bogs then bounces from 1500 to whatever it's set at. I checked my timing, it's good, but it appears to be a little sporadic at times when the engine lags. It will usually slowly lower when idling then bounce and hold 1500 rpm for a bit, slowly going back down and repeating.

Check TPS output, 0.4VDC at idle. IACV is getting coolant (lines are nice and warm) and it is getting it's 12VDC supply. What is output voltage so I can verify or compare?

I did tuneup also. Running OBD1 with 4-wire O2. What could be causing my terrible idle?

 

IACV. There is alot of threads about cleaning it, try that first. I had this same problem. Try cleaning it and then try to just unplug it, if the idle drops then it's probably the cause.

 

All actuators run off of a 12V supply and get the ground through a transistor in the ECU so you're IACV is reading normal, good!

 

It can still get 12V and ground, but still be bad. It probably just needs to be cleaned. If it's dirty or stuck it won't give you a code and will act like this.

 

^dayum. Go clean it sir, CRX guy sounds like he has some experience with this. Nice EE in your avatar by the way.

 

if thats not the problem, then maybe your throttle cable stopping screw is
holding the throttle open a tiny bit giving you the extra "umph" in your RPM's.