Idle Problem please help!

[subleg69]

okay so i have a 03 legacy 2.5, a few months ago i had an issue were sometimes i would start my car and the motor would stumble and die. this happened for a few days then the check engine light came on. it was for the air idle control valve. i took it out. cleaned it cleaned inside as much as i can. and the car ran awesome after. started right up idled perfect and even felt like it ran through the rpms better. i also put a new battery and alternator on. but since yesterday its started to stumble and stall, but not everytime. id like to say only when its cold yet it happened a few times if i turned the car off for a minute then started it again after being hot. i havent had the chance to look at it yet due to the holiday but can anyone tell me what they think is going on here? electric choke? im clueless right now. and no check engine light. Thanks Mack


p.s happy thanks giving to all

[chuckthefuk]

sounds like your IACV is going again. Get a new one and some peace of mind.
-Chuck

[subleg69]

ya think thats what it is? even though no check engine light has come on?

[chuckthefuk]

its very common that the CEL does not come on. I've swapped out several IACV's on N/A - Turbo subarus and the majority of them showed no signs of failing besides the lumpy idle or idle surges.

-Chuck

[subleg69]

really? is this a commen problem?

[chuckthefuk]

pretty common. just clean it again if your cheap or just buy a new one. You could try replacing the gasket. IACV's are just stepper motors. turn left / turn right.. they get fed a signal telling them how far to turn/move. the entire system works on vacuum so any leak in the system can cause lump idle issues.

Search on google "Subaru IACV problem" and do some research
-Chuck

[subleg69]

hmm yea for now im short on cash ill try cleaning it again but either way i think next week ima buy a new one. thanks.

[chuckthefuk]

look into that gasket.. honestly i'v changed so many from impreza to legacy new and old I cant remember what style or what gasket you may need.

Cheers and good luck
-Chuck

[subleg69]

i took it out a little while ago, i cleaned it again and there was a rubber o ring. which looked to be perfectly fine. i cleaned inside where the valve goes and the valve itself which weren't that dirty. when i put it all back together i got two check engine codes, P1516 and P1510 i cleared them, drove around for a bit and it hasnt come back on yet and is idleing not bad as of now. i think i need a new valve anyways.

[chuckthefuk]

Come on! You cleaned it and got CEL codes! Doesn't that raise some questions if the unit is really working.

P1510 *Idle Air Control Solenoid Signal 1 Circuit Low Input
P1516 *Idle Air Control Solenoid Signal 4 Circuit Low Input

Change it and go on with your life.
-Chuck

[subleg69]

yea i know, im buying one as soon as i have the extra 200 bucks lol

[chuckthefuk]

you could take a chance and get a used one for $60 off ebay.
-Chuck

[ShadowGT]

Thirty bucks is how much I paid for my IACV off of eBay. Here's the deal: Clean it the inside of it. If the valve door turns freely with no resistance and moves completely from open to close, the valve itself is OK, the electric motor on top has gone bad.
If the valve is seized up and it won't budge after cleaning it then yeah the valve is bad and probably by now that magnetic contact system in the electric motor is bad now.

So I bought this salvaged IACV from eBay. Mine, the valve turns fine it was just the electric motor going bad. So I took the motor unit off the one I bought and stuck it on mine. Used RTV gasket maker, reinstalled it and after 2 years I have never had a problem with it again. Now I also have a spare IACV valve body too.

Inspecting the old electric / magnetic motor, the magnet ring was broken and fragmented.

[subleg69]

im contemplaing buying one off ebay used, yet i don't know if i want to take that chance. if i was only rich haha