Meroveus

Hi all,
1994 Civic SI 1.6 L 5-speed
This started a few months ago.
I removed the air intake and determined that the IACV was open, passing air. If I blocked the passage, the idle smoothed out, but fast (2K RPM).
There is no evidence of gunk in the throttle body.

I replaced the IACV, but the symptoms are identical.
The old one looked pretty clean. How does a person test this part?

I have done the idle learn procedure, but no joy.

Coolant level seems good, but temp gauge is low -- about 1/4 of max on the gauge.

I've purchased a thermostat, but haven't installed it yet.

Distrib cap, plugs and wires were new in Jan, and the car ran fine for a few months afterwards.

No evidence of vacuum leaks using a propane torch w/ the flame off.
(Man o man I hate doing that!)

No check engine light.

Suggestions about what to try next would be helpful.
A solid reference to the *true* idle learn procedure might be helpful -- there is a wide variety of them out there.

What symptoms would I see if the ECU was faulty?

Throttle position sensor seems OK (according to the mechanic who confirmed the IACV diagnosis)

Thanks in advance!
--Meroveus

ezone

Replaced it with what? Used or new?


Does it have good coolant flow through the valve? It has to get HOT. If coolant circulation is blocked anywhere in any of those small hoses, the valve won't heat up and it will stay on cold fast idle.

Radiator stop leak and rust can clog the steel hose nipples on the engine and cause poor liquid flow through those hoses.


One symptom might be screaming high idle LOL