ICV goes to full closed position after turning key to ignition :/

[Jazz_89]

Hey you all

my car has a slightly high (but stable) idle speed, around 1000-1100 RPM. I measured the resistance across the pins and it is within spec. The valve hums when I turn the key to ignition.
But according to the Bentley Manual, if you close the valve manually and then turn the key, the valve should return to half open. In my case, it returns to fully closed...any ideas?

Thank you

[Coyote_ar]

i think i have the same problem, when you remove the valve and shake it, do you hear it move back and forth?

on a cold engine my idle is stable and high as yours at 1000rpm, when the engine is hot it goes down to 700rpm. the thing is in order to achieve this the accelerator cable is quite tense and i dont think the accelerator is fully closed. causing the engine to never go into fuel cutout when coasting. if i losen the accelerator cable, the car still idles but at 400rpm. the tach is still stable, but you can hear the engine strugling to keep idle (specially if the trans is in R or D the car will rock back and forth).

if i remove the valve cable, the engine wont idle, so the valve is doing something, but it may not be working at 100%.

have you tried to clean your valve with carb cleaner or WD40? i did that with mine when i initially bought the car, idle was a mess back then, and improved quite a bit. it was REALLY dirty inside.

[Jazz_89]

i think i have the same problem, when you remove the valve and shake it, do you hear it move back and forth?

on a cold engine my idle is stable and high as yours at 1000rpm, when the engine is hot it goes down to 700rpm. the thing is in order to achieve this the accelerator cable is quite tense and i dont think the accelerator is fully closed. causing the engine to never go into fuel cutout when coasting. if i losen the accelerator cable, the car still idles but at 400rpm. the tach is still stable, but you can hear the engine strugling to keep idle (specially if the trans is in R or D the car will rock back and forth).

if i remove the valve cable, the engine wont idle, so the valve is doing something, but it may not be working at 100%.

have you tried to clean your valve with carb cleaner or WD40? i did that with mine when i initially bought the car, idle was a mess back then, and improved quite a bit. it was REALLY dirty inside.

Interesting. In the Bentley's Manual there is a description on how to set the accelerator cable, by the way. I also heard that the throttle plate itself can get clogged and not fully close.

I cleaned the ICV with carburetor cleaner. Before I put it back in I want to measure the injectors resistance and the valve lash however, so I can tell you for sure tomorrow :)

[Coyote_ar]

when you remove the ICV and move it along the axis of the motor, does it make a sound like clank clank? like there is no resistance or anything stopping the valve from free movement? mine does that, and im not sure if its supposed to be that way.

[632 Regal]

Clean the valve out with carb cleaner, brake cleaner works but dries out all the seals. Until it moves freely you will have problems. Simple but real.

[Jazz_89]

If I remove the ICV from power, I can easily turn the valve with a screwdriver.

Now I cleaned it with carb cleaner, let it dry. The idle speed still is about 1000 stable, even if I turn all the electrical components on. I will try to disconnect it while in idle, to see where the last valve position was.
Why does it have 3 pins, by the way? Two motors and one ground?


Have a nice weekend

[Coyote_ar]

as per the wiring information i got for the megasquirt.

the ICV has a +12v coming from the fuel pump relay.
and 2 ISV leads.
ISV1 open
ISV2 close

I guessing the function is to move and hold the vale in an open position, then the other one for a closed position. there doesnt seem to be any kind of mechanical return mechanism. so its not an on-off valve. the last state you activate, is the last one that the valve will hold. this is why you can easily move it with the screwdriver when there is no power.

[shogun]

Bentley manual says:
with engine running, check that idle speed control valve is buzzing.
turn on AC or shift car into drive. idle speed should remain steady or increase slightly.
if valve is not buzzing or if idle decreases, stop engine and disconnect harness connector from valve.
check resistance of valve accross the terminals. Test values for M30 are listed below:
terminals 1 and 2 20 +/- 2 ohms
terminals 2 and 3 20 +/- 2 ohms
terminals 1 and 3 40 +/- 4 ohms.
note: if you suspect an intermittent fault, lightly tap the valve while testing resistance.

with the valve harness connector disconnected, check for the battery voltage at red/white wire in connector wityh ignition on.
if there is no voltage, check wiring between connector and main DME relay.
the idle speed control valve receives positive + battery voltage from the main DME relay.
if voltage is present as described, check wiring between ECM and valve. If no wiring faults are found, check ECM output signal valve.

note: there are some additional inputs to the control moduls that affect idle speed, such as throttle psotion, AC on signal, or automatic drive position. check these signals if idle problems persist.

[Jazz_89]

Alright, thanks for the responses!