91 Civic Si D16A6 stock. Rebuilt engine.

for some reason it just idles at 1000 rpm (according to the dash tach)

cleaned iavc, fis, throttle body. Bleed the coolant system correctly. Probably adjusted timing, and idle according to manuals. Brake booster tested fine. Valve lash completed and in spec.

I guess it has a built in fitv or tv to the intake manifold that runs coolant to the bottom of throttle body from the thermostat housing, but no tsb on that.

Didn’t want to mess with the idle screw but tried it out to just turn a quarter turn and have it bottom out.

The engine idles great. Just at 1000 rpm.

What an I missing? Recommendations please. Thanks!

 

high idle can be caused by a vacuum leak - check all vacuum lines - could also be the PCV valve

 

A lot of my idle problems were finally solved by just buying a new (not used) idle control valve. I had also cleaned mine a few times, but I think it was internally sticking. Also you want to check your TPS voltage at idle (at idle stop on TB).

 

I have same problem but mine idles at 1100 rpm, I replaced my IAC adjusted the fast idle valve, replaced map sensor on throttle body. Now I going to check my vacuum hoses and the PCV valve. Please let me know if you fix issue with yours.