I bought a 93 civic ex with a d16 z6 swap with a y8 head and high compression pistons. I knew the car had a bad head gasket and I fixed that problem. New gasket head studs also new injectors plugs and wires. So after all that the car started right up but idles at 3000 rpm's. that's the problem. The tps is good and the throttle is not cracked or anything. Once the car warms up a little it will idle around 15-1600. The idle doesn't fluctuate it's just too high. Could this be caused by a dirty iacv, andnwhat else should I check?

 

Does the throttle cable have play or is it tight? try removing the throttle cable and see if it idles normal.


grab a bottle of brake cleaner,carb cleaner and spray around all vaccum lines,throttle body to manifold surface and head to manifold surface if the idle changes you have a vaccum leak.

also did you reconnect the 2 little coolant hoses on the IACV? if you didnt and coolant isnt flowing to the VALVE it will cause the vehicle too idle high.

 

The throttle cable is tight. I will have to try the carb/ brake cleaner trick. And I haven't cleaned the iacv yet, I was just wondering if that was dirty it could cause the car to idle this high even though its not fluctuating.

 

the throttle cable should NOT be tight!
It should have about a half inch of play (up and down)


Go remove your throttle cable from your throttle body and start it with out the cable see how it idles.