95 prelude ides at 1300 rpm when warm?

Question

I have a 95 Honda Prelude and just had the radiator replaced. Immediately after that, I had to saw off a hose because it was leaking at the clamp. It was not idling right after that so I bled the coolant (many times). Ideally, when I start it cold (even though it's 70 degrees) it should idle around 1100, and after warming up, drop down to 700-800rpm's. Cold, it idles between 1500 and 2000. When warm it varies between 1000-1300. About a year ago I had to replace my Fast Idle Thermal Valve since the idle was surging from 1000-2500 non-stop. It is not leaking coolant, has been bled using the bleeder valve by the thermostat, and has a fairly new FITV. I know it could possibly be a vacuum leak, but I also read about resetting the idle by unplugged the FITV, adjusting the screw and resetting the ECU. Do you have any other suggestions? Thanks.

Answer 1

The first thing to do is to do the idle re-learn procedure below.
You will want to check for vacuum leaks as you mention. The other item is the power steering load switch that could be causing the idle to raise up if it is giving an erroneous signal that you're under high steering load. Its a slim possibility, but one none-the-less. The other thing is to have the valves adjusted if they haven't been adjusted in a while. The valve adjustment affects the idle quality but I don't think it will cause the rise in rpm that you're reporting.
Hope this helps:

Here's the idle relearn procedure. You'll want to disconnect the battery and leave the cables off for about 5 minutes, then reconnect the battery before you do this.
The idle learn procedure should be done
whenever you do any of these actions:
• Reset, replace, unplug, or reprogram the ECM/
PCM
• Disconnect or replace the battery
• Do engine work that requires R&R of the
intake manifold or the throttle body
To allow the ECM/PCM adaptive idle speed
system to learn and adjust the engine idle speed,
here’s what you do:
• Make sure all electrical items (A/C, audio unit,
defogger, lights, etc.) are turned off, then start
the engine.
• Let the engine reach its normal operating
temperature (the cooling fans cycle twice; the
coolant temperature is about 194° F).
• Let the engine idle for at least 5 minutes with
the throttle fully closed and with all electrical
items turned off.
• If the cooling fans cycle on while doing an
adaptive idle learn, add the time the cooling
fans are on to the 5 minute adaptive idle learn

Answer 2

you have to disconnect the FITV or IACV to correctly set the idle.. your problem should clear up after that..