1991 IACV

[Blu Bug]

I have a 2.2 non-turbo motor out of a 1991 Legacy with a manual transmission. The solenoid (two pin) is bad. I have tried multiple sources to buy a new idle air control valve, but no one has them anymore. Does anyone know of an obsolete supplier or a lead to someone that can rebuild the solenoid?

 

Thanks in advance,

 

Blu Bug

[Fairtax4me]

This is a common problem on the 90-91 years. The common fix is to swap the wire harness to run the 3 wire IAC. I don't recall specifics on this off the top of my head. Lots of info on the swap at LegacyCentral.org though.

[Blu Bug]

I have this motor in a baja bug and I am currently using an aftermarket computer that only sends out a PWM signal for the solenoid. I will do some searching on LegacyCentral, thanks for the lead.

[Blu Bug]

No luck on finding info related to my needs. Does anyone know if I could remove the spring from the solenoid to make it closed all of the time and just use the thermal spring that is heated by the coolant, so I have at least cold start air vacuum?

[upnorthguy]

Seems like this part would be a perfect candidate for a salvage yard find.  Have you looked near you?  

Not as many of the gen 1 (90-94) Legacy cars left in the yards here in VA.  I looked at list for the yard near me and there is only a 1993 listed.

[Fairtax4me]

Seems like an aftermarket ECM should be able to do either. If nothing else you could gut the stock one and put a Bosch 2 wire IAC in line in the IAC tube.

Lots of cars european used them so they're generally easy to find and don't often fail.

[Blu Bug]

The Bosch 2 wire IAC installed in line sounded like a great idea so I did some searching for Bosch IAC valves and ran across a post where a fellow who had a similar aftermarket ECM to mine (only one PWM output for idle control) and he was hooking up a three wire Bosch IAC valve. He connected the center pin to 12v, connected one of side pins through a resister to ground and connected the other side pin to the EMC idle control output. He said the resistor ground would act like the spring of a two wire solenoid valve. The three wire IAC (automatic transmission) valves for my motor are still available and easier to find used than the two wire (manual transmission) valves. If they work like the Bosch (one power and two grounds) the resistor ground idea sounds interesting. Any thoughts?

[Blu Bug]

Does anyone know if the subaru valve works like the fore mentioned Bosch valve?

[Fairtax4me]

I'm not sure, but the older Subaru FSMs tend to have decent descriptions of how the fuel/ignition system parts work.

 

You can also look up the ECU pinout and wire diagrams to help figure out how it works.

 

Check here: http://www.main.experiencetherave.com/subaru_manual_scans/

 

95,96,97 all use the same IAC. IIRC 92 does as well.

[Gloyale]

You can install a 3 wire and hack it.

 

I did this on my wheeler for an idle up switch for winch/jumpstarting.....

 

So this is how.

 

1. run 12v+ Ig. switched to the center pin of 3 wire IAC

 

2.  Connect the center pin of a SP-DT Switch to ground.

 

3.  Connect the other 2 pins to the IAC pins 1 and 3.

 

Now this is for the basic idle/up idle down.....When the switch is flipped one way.....the  "OPEN" side(pin 1of IAC) is connected to ground so the gate swings open increasing idle.  Flip the switch the other way, and the "closed" side is grounded (pin 3 of IAC).

 

Now this is the weird part.......The ECU will not like having no idle control...and will throw a code.......here's the hack for that

 

MT:   Connect a small incadesant bulb...(turn signal or marker) between the Original 2 wires from the ECU to the IAC........this will keep the ECU happy mostly that it sees a load it thinks is the IAC vavle.

 

AT: Connect 2 small bulbs, (or a Dual filament bulb)  Each bulb (or filament) shall be connected to a power source on one side.....and 1 each grounded by the 2 original IAC wires that come from pins 1 + 2 of the ECU....so the ECU sees 2 coil circuits it thinks are the IAC.

 

*NOte*    When using the idle up function.......after a certain amount of time.....or whenever fully warm already......the ECU will CUT FUEL to the #1 cylinder at idle.......since it senses the idle RPMS are higher than it should be....but can't control it (it'll try....fun to watch bulb light and dim)

So this will result in a slight "loping" or "miss" with the throttle closed at idle.....but the switch flipped to "open" for idle up.......Will throw CEL during this time too but goes out after driving with switch "closed" for normal, warmed up, low idle.

 

 

Oh yeah and also you could just block off the ports for IAC and spend 30-secs with your foot on the gas till it warms up to idle and forget about it.

Edited August 13, 2014 by Gloyale

[Blu Bug]

Thanks for all of the input. As usual I am over thinking my situation. Blocking off the port and warming up the car by working the throttle is what I should probably do.