The function of the IACV a.k.a. Idle Air Control Valve is to adjust the idle based upon the amount of air entering the engine, then the computer reacts to this information by adjusting the cars rpm.
Why should I clean my IACV?
If you that have an erratic, fluctuating, or lumpy idle or if you have high idle after your car warms up. Or if the problem has been present for a long time, the car may stall sporadically at idle.
Small 1/4” ratchet socket wrench
Needle nose pliers
New IACV gasket (Honda part# 36461-PAA-A01)
Old rag to absorb over flow from removing the coolant hoses
Misc tools (to remove intake hose)
Step One: The idle air control valve (IACV) is mounted on the rear of the intake manifold (IM) near the throttle body (TB). You’ll have to remove the intake hose at the throttle body to gain clearance to the rear of the IM.
Step Two: There are two 10mm screws attaching the IACV to the IM, one at the top that is partially visible and the other is lower and out of view. You’ll have to feel your way back there and remove that bolt. Remove the gray plug on the right side of the IACV.
Step Three: Remove the blue plug on the TB. With the needle nose pliers,at the TB end, pull back the clamp and remove the coolant hose attaching the IACV to the TB. At this point the IACV has enough slack to pull out from behind the IM & TB. Now pull the IACV out into the void left by the intake piping. Remove the last two hoses, there is one with a clamp and one without. Viola the IACV is free.
Step Four: With the IACV in hand remove the gasket and toss it. Look at all the schmootz in the valve. Spray the IACV vigorously with the carb cleaner, cause as you can see it’s very clogged and probably has tons of carbon buildup.
Step Five: Let it dry completely, then put the new gasket on and connect the two hoses, install the two bolts, connect the coolant line to the TB, reattach the blue plug at the TB, and the plug on the IACV. Re attach your intake pipe/hose and Booooyah!….you’re done.
Now you can enjoy a smooth idle sputter free.
You should not start the car with the IAC out. The PCM (or ECM as Honda calls it) will have no reference for idle and the engine will over rev. The IAC valve actually works a lot like the stepper motor in a printer. It even does a rail check before start up (just like a printer) to check IAC movement and so that the PCM can gain a reference point to adjust idle from.
Cleaned my IACV today. Here are some pictures.
Put everything back in reverse order and that is it.