My 1997 Legacy GT (with '95 EJ22 engine) has been idling poorly lately- fluctuating, lower and rougher idle and a resonating noise coming through the intake. It has also thrown a couple of P0505 codes which makes the IACV suspect, but the IACV valve opens and closes smoothly.

 

Then today I pulled the alternator belt as I've been hearing a bit od whine from the engine and was trying to isolate it. When I started the car, the idle was normal and smooth. I restarted it several times (until the battery died) and the same result.

So maybe a grounding issue, or maybe the alternator is overcharging (voltage too high), maybe ECU is heading south?

 

I did check battery voltage and it was right around 12 volts with the engine off and around 13.5 volts with it running (I have an old dial type voltmeter so it's a bit hard to read) 

I know the alternator is doing its job because 3 starts without it hooked up killed the battery pretty quickly.

Here's a video clip- first with it running well with the belt off, then running poorly with the belt back on: 

Edited December 22, 20178 yr by Stevo F

The belt also drive the Power Steering Pump.  How's it?

 

Also check all if the battery connections.  Clean and tight?

good idea ^^^^ power steering frequenly makes a whining noise = look for bubbles in the PS fluid tank. do a search. common issue. I've had to replace o-rings on bith my soobs' ps suction hose adapters.

 

check the IACV hose that connects under the intake tubing, maybe it's cracked.

The power steering pump spun freely with the belt off. I think the whine could be coming from either the alternator or power steering. but not very load, and I doubt either would throw off the idle.

 

The IACV hose is in good shape and connected with clamps. I also checked the operation of the vale in the IACV and it moves smoothly.

Removing the engine load doesn't prove anything. It just means the IACV was at a point where it could supply enough air for a decent idle when not loaded, but couldn't compensate when loaded.

 

If you have codes for the IACV then try a used one or get a new one from the dealer while you still can.

 

The other possibility for idle control codes is a bad inhibitor switch on the automatic models.

 

GD

+1 swap in another IAC, you want to track the known issue.

Thinking of picking up an IACV but $230 new- Rock Auto, or $65 used- Ebay.

 

I removed the solenoid portion from the top of the IACV, and the shaft for the valve moved smoothly back and forth, so it doesn't seem dirty, which makes me think maybe the solenoid itself is bad. I could take that part off my wagon and try it on the GT IACV, but hate pulling parts from a perfectly good running car to experiment on another car.

3 engine starts killed the battery seems to me the battery is on the way out. Alternators in good shape will pump out 14.7 volts. 

$65 is high. You can get one cheaper they’re not worth much, but demand is so low few people bother trying to sell them. I’ve got a few lying around by I don’t think for an EJ22, just one on a complete manifold that’s for an engine build so not gonna remove it.

 

Post in parts wanted section someone may have one. I’ve got a bunch but 90s stuff is all rusted away and not worth holding onto around here for me.

Not sure if you can get sensors but maybe find the cheapest intake manifold or core engine and ask.

 

Www.car-part.com

Battery is only 3 or 4 months old.

 

I removed the solenoid portion from the top of the IACV, and the shaft for the valve moved smoothly back and forth, so it doesn't seem dirty, which makes me think maybe the solenoid itself is bad. I could take that part off my wagon and try it on the GT IACV, but hate pulling parts from a perfectly good running car to experiment on another car.

The solenoid on top is not meant to be removed, adjusted, or tampered with in any way, or you will have idle problems. The position of the solenoid is set at the factory in a way specific to the valve its on. There's no way to get it back to the factory setting if it's removed, and there's no way to match up a different solenoid to valve combo to the correct setting.

If you have a spare, you can swap the entire assembly, but do not try to swap just the solenoid on top.

As it is now, the one that you removed the solenoid from is basically junk, you might get lucky and get it back to "close enough", but it will never be right. You're better off to oss it and get a new/used valve.

Just reading thru this thread.... To me All points to a failing, not yet failed, Alternator.

 

Battery not fully charging,,,,,, not over 14V when running...... possibly a defective diode in the diode Trio injecting a small amount of AC into the system causing the bad idle.....

 

But those are my observations just reading the symptoms as presented.... remember we can't touch, see, hear or test anything .... just read whats in the thread.

Just reading thru this thread.... To me All points to a failing, not yet failed, Alternator.

 

Battery not fully charging,,,,,, not over 14V when running...... possibly a defective diode in the diode Trio injecting a small amount of AC into the system causing the bad idle.....

 

But those are my observations just reading the symptoms as presented.... remember we can't touch, see, hear or test anything .... just read whats in the thread.

+1

 

ac ripple will cause idle issues and pulsing in lights when it gets bad.

 

although, Subaru voltage at idle should be not more than about 12.8~13v within a few minutes of startup.  they should not "sit" at 14+ volts at idle.....they aren't GMs.

 

GM does this because their wiring setups are long and overly complicated so to have 12v at an accesory they have to have 14+ at the battery to account for the line loss/volt drop.

Being a GT, if it still has the hood with the scoop, check the engine to bulkhead wire harness connections. My sister's 97 LGT had a bunch of weird issues and it turned out to be corrosion in one of the connectors.  The one with all four ground wires specifically.  Hers has 250k+ on the clock, and the rubber terminal insulators have dried out and don't seal well any more. To make matters worse, the hood scoop block off plate has a drain hole that allows water to drip right on the connectors.

I rechecked battery voltage on my old voltmeter. It read 12.2 volts not running, 13.2 volts running. I checked AC voltage it was 25 volts not running and 30 volts running. That seemed crazy (maybe the old voltmeter is FUBAR).

 

Also, as a comparison I checked the same on my '98 Legacy wagon- It read 12.5 volts not running, 13.7 volts running. I checked AC voltage it was 25 volts not running and 30 volts running- definitely suspect an issue with the voltmeter with those AC readings.

I have plenty of spare IAC's.  $10 and $15 for shipping.

I have plenty of spare IAC's.  $10 and $15 for shipping.

If they're known to be in working condition I might take you up on that.

Working when pulled.

I can send a couple of them if you want.

I also have the gaskets.

 

You have to be careful with the coolant lines or replace them when you remove the IAC.  As long as you break them free before removing.

Working when pulled.

I can send a couple of them if you want.

I also have the gaskets.

 

You have to be careful with the coolant lines or replace them when you remove the IAC.  As long as you break them free before removing.

I PM'd you

The only thing I noticed that sent me down the right path was the battery voltage parameter on the scanner.  The ecm was reporting voltage around 2v less than what was at the battery, while the tcm was within .2v. 

IAC's sent.

Larry

IAC's sent.

Larry

Thank you sir! Hopefully once we get out of the deep freeze here, I can work on loosening the 23 year old coolant lines and see if I can remove the old unit.

Hats off to Imdew! I received the IACV's today. I went ahead and installed one of them (I already had a new gasket) and the idle is now fine. The idle did spike up for a second a couple of times when first starting the car, but didn't repeat when I ran it again (maybe the ECU and the new IACV had to get acquainted). 

 

At first I was a little intimidated by the job as the IACV had a lot of stuff in the way. Once I removed the PCV hose (which split due to age, but I got a new piece of hose for it) removed the two coolant lines, and was able to get a socket on the 3 mounting bolts, the rest was easy.

Sweet another Subaru back on the road!

Glad it all worked out.