Subaru and IAC

[GS guy]

Another neub here, first post. I will be installing a MS-II on a JDM EJ Subaru engine.

My first question: has anyone figure out the operation of the Subaru IAC valve? It's a 3-wire hook up, so at this point I'm guessing it's some kind of PWM valve? It also appears to be a type of rotary valve, as opposed to poppet operation. Is there any way to perform a simple bench test of the valve to see how it operates - without the Megasquirt?

I'm trying to decide whether to keep the OEM valve, which looks pretty sophisticated even having a water line hook-up - though it's bulky and ugly and uses a huge air line - like 3/4" or so(!), or switching to a "known quantity" in terms of MS use, like the Jeep stepper valve. The main intent of the vehicle is a Sunny day driver, but I want the engine to operate down to about 45-50F. The water heated IAC valve seems a bit overkill for this purpose. My thinking is if I use the Jeep valve instead and mount it to the engine block, that should provide enough heat to prevent icing?

Any advise appreciated!

Jeff

[GS guy]

Well, after thinking this through a bit more I think I will just adapt the Jeep stepper motor. Should be easier to hook up and get operational than the OEM valve.

On a good note I did some temperature/resistance testing of the OEM water temp sensor - the readings are identical to the Bosch sensors, so this saves from trying to adapt the much larger GM sensor to the 12 x 1.5mm opening. Just have to come up with an additional sensor mount for the dash gauge. Not sure what sensor mounting is used by Autometer?

Jeff

[kay95]

i have a EJ20g that i plan on puting into my impreza and my plan was to just get a solenoid valve and use the fidle to open fully but use a restrictor to control the idel speed

[KGB]

Looking at my wiring diagram, my stock idle valve (MY00 2.5RS) only needs 2 wire - I'm thinking it's a PWM setup?

[fiid]

I have the JDM idle valve working with one side (closed side) going through a 20ohm resistor to ground and the other side going to the FIDLE pin. The MS-Extra code is able to keep a fairly solid idle with closed loop control.