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ICV - Idle problems - Subaru STI V7


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Hi Guys

Please assist. We have installed a brand new G4+ Unit on a Subaru STi V7.

The idle control is non existent, and we noticed that the ICV does not even move when car is on or started.

In the configuration for the ICV stepper motor, it only has an option for a 4 wire and 6 wire ICV. The Subaru comes standard with a 3 wire ICV ??

 

What are we missing ? Whether I plug out the ICV or not, idle stays high.

ICV = Idle Control Valve

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How do you have the IACV wired up?  It will just be a power, ground, and a signal from the ecu in most of the ver7-9 motors. 

If its an older idle valve it will be a power and 2 signals from ecu.  One to open, one to close.

I would take the idle valve off and test it on the bench.  I have seen a ton of those get all gummed up and not work correctly.

 

As for the 4 or 6 wire idle valve, that only pertains to stepper motor idle valves, which you should not be dealing with on this application.

 

As for idle staying high, is the idle rpm higher than the target idle speed + the rpm lockout?  If so then the ecu will not try to do anything about the idle speed due to the rpm being above its control range.

 

I would disconnect the idle valve and get the vehicle to idle nicely with out it.  Maybe have it idle a touch lower than what you would want.  Then get the idle valve working for the fine adjustment.

Good luck,

Brad

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We did not wire it, it is a straight plug into the subaru loom. We can't unplug it, because default setting is open on the icv, it revs almost 2000rpm. Under the link ecu idle settings, it only gives us 4 or 6 wire to choose from. We purchased the straight plug in stand alone ecu made for the harness on this subaru sti v7.
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I've got the same ECU/ISCV on my car.  For me the ISCV is on Aux 3, setup  as "ISC Solenoid" with a frequency of 200hz.

In the Idle Speed Control page, I'm just running open loop control, so the idle speed mode is "Open Loop Sol/Stepper".  Stepper Motor Type is "Unipolar (6 Terminal)"

For my setup in the ISC Base Position Table, I've got 49.5% at 0degC and 36% at 90degC.

Have you done a solenoid test to make sure your assigned AUX runs through to the ISCV?

While you're troubleshooting I'd also zero out the idle up step tables

Edited by JMP
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Under the link ecu idle settings, it only gives us 4 or 6 wire to choose from. 

Your idle control is done by a solenoid - so you can ignore the "stepper motor type" setting.

As Brad mentioned earlier its most likely the RPM lock out thats preventing the idle control from working.  I suggest you post a log of the engine idling and also a copy of your map so one of us here can take a look.  Follow this video on how to do a PC log if you dont know your way around yet: https://www.youtube.com/watch?v=_P1LRANeO4A

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First check the idle speed with the solenoid unplugged.

If the idle is excessive with the solenoid unplugged then this indicates there is too much throttle opening or there is an air leak into the engine.

Get the idle nice but slightly low with solenoid unplugged then connect solenoid and start to adjust the idle control in open loop mode.

Once happy in open loop you can go to closed loop if you wish.

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First check the idle speed with the solenoid unplugged.

If the idle is excessive with the solenoid unplugged then this indicates there is too much throttle opening or there is an air leak into the engine.

Get the idle nice but slightly low with solenoid unplugged then connect solenoid and start to adjust the idle control in open loop mode.

Once happy in open loop you can go to closed loop if you wish.

Whether I unplug it or leave it in, idler is the same, almost like it does not connect to it. We even removed the icv and switched the car on and started it, but no movement on the icv, even with a second sensor we had

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Next step is to check the power and ground supplies to the solenoid. You can also check the output of the ECU with a test light. If you put the ISC output to test on the light should turn on.

Hi there !

We just tested, we have 8V on the connector, so wiring all good. Does the 8V power not create an issue?

Under auxiliary 3 is my ISC Solenoid

How do you have the IACV wired up?  It will just be a power, ground, and a signal from the ecu in most of the ver7-9 motors. 

If its an older idle valve it will be a power and 2 signals from ecu.  One to open, one to close.

I would take the idle valve off and test it on the bench.  I have seen a ton of those get all gummed up and not work correctly.

 

As for the 4 or 6 wire idle valve, that only pertains to stepper motor idle valves, which you should not be dealing with on this application.

 

As for idle staying high, is the idle rpm higher than the target idle speed + the rpm lockout?  If so then the ecu will not try to do anything about the idle speed due to the rpm being above its control range.

 

I would disconnect the idle valve and get the vehicle to idle nicely with out it.  Maybe have it idle a touch lower than what you would want.  Then get the idle valve working for the fine adjustment.

Good luck,

Brad

Confirm please where the "rpm lockout " is you referring to ?

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Hi there !

We just tested, we have 8V on the connector, so wiring all good. Does the 8V power not create an issue?

Under auxiliary 3 is my ISC Solenoid

Confirm please where the "rpm lockout " is you referring to ?

I looked at your cal file.  The rpm lockout is only pertinent to closed loop ISC.

 

 

Edited by Brad Burnett
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idle_air_1.thumb.PNG.e8ddfafa997a23da064

idle_air_2.thumb.PNG.441d2fb2dcfdd7ae4dc

Pin 1 should go to ECU pin C10 (Aux 3)

Pin 2 should be +12V from Main relay. This is the same supply as the injectors.

Pin 3 should be GND.

Check between pins 2 and 3 and see what voltage you have, I would expect +12V. Try this with the solenoid disconnected and connected.

Scott

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