Rep Power: 0

Hi,
I'm suspecting the IACV to be occasionally stuck open on a Civic VII 2004 1.4iS / EP1 and would like to check it electrically.
Does someone know the correct values of resistance between the pins?
Is one of the pins a feed-back channel or so?
Should it close completely when not operated?

I have removed the valve now. It is a Denso 136800-1912. It is only lightly dirty. It is open when not operated.
I can measure about 60 Ohms between one of the outer pins to the center pin. When I apply power here the
valve opens shortly (with + on center). Otherwise, I measure some diodes or similar between each outer pin to center pin.
The other outer pin to center has high resistance (not stable, looks like a capacitance).

Regards,
vbar

 
Rep Power: 224

Assuming the IACV is similar to what we have here in the US you should be able to take the motor assembly off the valve. You can then verify the valve spins freely by hand.

 
Rep Power: 0

Thanks for your hint. I decided not to take off the motor assembly; I'm not sure if I'd get the stuff back together with the spring etc.
Also, the screws are too tight and have some uncommon socket.

Using an arduino board I was able to test the valve though, connected approx. like this:



I'm not sure I got the pinout correctly, but the valve follows nicely the potentiometer. If I went below 10% duty cycle or above 90%, the valve went back to the default position.
Exchanging GND and the PWM signal also worked, but the usable range was smaller and it was not possible to close it completely.
So I just cleaned the IAC valve and put it back.

Somehow the engine occasionally gets too much air. The idle rpm is too high then (ca. 1200) and pressing the brake a few times brings it up to ~2000.
The car is then also not running smoothly when driving in 2nd gear at lower RPM for example.

Once I tested it was again driving really well, very little RPM change when pressing the brake at idle, also and normal idle rpm.
The service did not find a problem, said the tubes and so on looks good. Brake amplifier keeps the pressure. No indication of a vacuum problem. Hmm...