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3-wire, 6-wire idle solenoid


Matt Howe

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Hi I have recently purchased a LinkPlus G3. Im planning on wiring it up to my version 3 subaru sti. The factory idle control valve on the v3 is a 3 wire. However I want to switch to a 6 wire solenoid from a later model subaru as the valve is integrated into the throttle body and it nice and neat. I have seen the v5/6 base maps that come with the link and i'm aware i could use another 3 or so link outputs to control the new solenoid. However, I would like to know if there is a way of controlling the 6 wire solenoid as if it were a 3-wire. Would it be possible to find out which wire on the 6-wire solenoid completely opens the valve and which closes it? Or simply wire up one side of the motor?

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The 6 wire stepper motor MUST be wired to Aux 5,6,7 and 8.  Personally I would not recommend using it.  It can be controlled perfectly in closed loop mode, but is a dog for startup.  With a LEM G3 the stepper must be reset at key on which means it is moved fully open then back to the startup position.  V5-6 stepper is slow moving and opens a very long way.  It means that if the engine starts during this process it will do a big over-rev.  The solution is to lock the engine from starting until after this process is complete which causes it to  crank for about three seconds before firing (this is all configurable).  the three wire solenoid will give better idle speed control without this problem occuring as it can be moved to its starting position almost immediately...

I thought all subaru's used a three wire solenoid anyways. A round gold one with two cast pipes at right angles and bent steel pipe coming out the other end.  Anyways, a three port solenoid would provide more stable boost control.

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Thanks for the info Ashley Up until 99 the subaru idle control was a seperate unit and had the pipes as you've described, from then on they were integrated into the throttlebody. Maybe there is a 3 wire version that is integrated into the throttle body? I will have to hunt around to see what i find. With the seperate 3-wire version I currently have, will I need to connect the supply of coolant to it for temperature dependence? If the system can be tuned without the supply of coolant that would be preferable. As another option, I have seen some people scrap the idle valve altogether and open the butterfly a little bit to set the idle speed. As the car warms up the timing is adjusted to keep the engine running smoothly.. It seems to work for them, but I am not sure of the pros/cons of doing this. Can you advise? Thanks very much

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The pipes I was describing were the boost solenoid.  I know exactly what valves were fitted to what subaru motors, and can confidently tell you that they all have three wire solenoids except v5-6 which have 6 wire stepper.  Like I said, my recommendation is to use the three wire.  Coolant is plumbed through ISC devices to prevent them from freezing on very cold mornings.  If you live somewhere that doesn't get overly cold then it wont be a problem.  I wouldn't advise just jamming the throttle open and altering timing.  Firstly you cant have nice repeatable closed loop idle and secondly you have to alter the timing over the whole range which is not desirable.  I dont remember seeing coolant hoses running to subaru three wire solenoids, just a big pipe and a bolt on flange to the manifold, but it has been a while since I looked.  If you can run the plumbing, then do so.  Subaru didn't spend millions developing that valve for nothing!  Anyways, in short... definitely run ISC control (you will hate it idling inconsistently and stalling), preferably use a three wire solenoid and if you can, leave the plumbing there.

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  • 2 months later...

Thanks for the info Ashley. Just another question, does the idle control valve play a role in antilag? Or will antilag run seperatly without using the idle valve or any other type of valve that would need to be retrofitted? Also, a friend and I and building an old audi quattro. At the moment we have an S6 engine (AAN) running with the factory motronic ecu. We would liek to fit an aftermarket EMS to it. Can you advise whether you have done much testing with audi inline 5 cylinder engines? An LEM G3 looks like it has all the features we need, we are just not sure whether the extra cyliner makes things difficult for the EMS or not.. The AAN engine uses a coil on plug setup. Cheers!

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Anti-lag will not run using the idle control solenoid.  The ISC valve can not deliver enough air for anti-lag, an external valve or throttle opening device is required. 

The 5 cylinder engine should not be a problem, we have done Audi 5 cyl and Honda 5 cyl engines in the past with no issues...

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There is no simple way around that.  You will have to use a LinkPlus G3 or convert the motor to distributed...

I think the best devices to increase idle are ones that move the throttle mechanically such as an EA Falcon idle motor, or a mechanical linkage.  There are same large 2 wire ISC solenoids used on european stuff that also do the job.  I think we also sell the big ISC solenoid.  Contact sales...

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  • 11 years later...

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