IAC Valve Question

Hello all,

To my previous posting on a rough idle on my 95 Integra LS (90k).
I'm following the guidelines on adjusting the Idle Speed. The factory
manual suggests that with the IAC disconnected that the Idle speed
should be adjusted to 480 +- 50 Rpm. If I adjust it I can't get below
750 without closing the adjusting screw completely. I had adjusted the
screw about a 1/2 turn from the closed position, reset the battery and
started the car up and the RPMs showed about 500 and the car was
stuttering almost ready to shut off. When I adjusted it to a calm
level, and disconnected the IAC again, the RPMs showed close to 1k
RPMs. Some previous posted had suggested that I investigate the valve
timing but the factor manual doesn't suggest that I even look at that.
Could I have a malfunctioning IAC Valve even though the check engine
light is not on? I also heard a hissing sound so I may have a cracked
hose which is leaking air but I'll check that tomorrow. Although I
have done a lot of repairs to my car, this is new territory to me so
any help would be greatly appreciated.

Thanks,
Nick

 

How clean is the throttle body? Clean it up and try again. Carbon buildup
may be holding the throttle plate slightly open.

Does your manual say anything about a throttle dashpot? In the previous
generation, a defective dashpot could affect idle speed. If you have one,
try disconnecting it from the the throttle linkage (or even just from
vacuum) and see if you can then adjust the idle correctly.

And yes, definitely make sure the air intake tube is not split or loose at
the throttle body and that all vacuum hoses are intact.