jwsutto4340

I have a 93 Prelude 4WS with the factory H23 engine in it. Originally my car would rev from about 1500 to 2500 rpm when the engine was cold. Once it reached about 150 degrees operating temperature, it would idle normally at about 750. I thought the problem was the idle air control valve and I bought a brand new one from a dealership. It didn't fix the problem. The next thing i did was "reassemble" the fast idle valve by stretching the spring on the inside and putting it back on. I also adjusted the idle screw located on the top of the throttle body. After playing with the fast idle valve and the idle screw, it stopped the revving. I was pretty convinced that maybe just the idle screw needed to be tightened because i tightened it right after i "reassembled" the fast idle and it immediately stopped. I recently changed my brakes on my own and it started revving at idle again but now it does it at full operating temperature. Any time i take it out of gear it will rev from between 1100 and 2100 rpm, even when rolling in neutral at 70 mph. I was thinking maybe a vacuum leak or something i did when i changed my breaks. Can anyone help me?

G_Loc

Check the voltage on the TPS sensor. It might be showing a higher voltage at closed throttle.

Also, have you tried bleeding the cooling system?

__________________

jwsutto4340

Could you run me through how to check the voltage on the tps? And what should it read if the tps is the problem or not the problem? I will try bleeding the cooling system, but just so i remember correctly...the engine needs to be warmed up and running while i bleed it using the valve right? Thanks for the help.

jwsutto4340

I was leaning toward the fast idle valve, but im not sure...and i already spent 200 dollars on the iac valve (which i thought was the problem) and i couldn't return it or find a buyer. But i don't think there is any way to test the fast idle valve. It's not electronic as far as i know, and it just has a spring inside it that contracts and expands.

Shovhed1

I had a similar problem. Intake manifold gasket bad. suckin air.

ChicagoRSX

its not a spring, it's called a thermo wax plunger, and I've never heard of streching the spring to make one thats going bad go good. the way to test the fast idle valve is to bypass it. if you do that and the problems stops, there you go.