legacycentral bbs

I have a '91 Legacy EJ22 installed in my VW vanagon. Idle has been fluctuating and sometimes stalling. My thoughts are the IAC valve, solely because there is a funny fan like sound coming from it. When it is silent, then engine's idle fluctuates. Idle will smooth out when the funny noise is present (which happens after 5-6 fluctuations) I pinch the intake hose to the IAC and the sound goes away.

Is this IAC noise telling me the IAC valve is on its way out or can cleaning it make any difference?

Whats the best way of cleaning the IAC? Preferably with out having to remove it.

FYI - I have no codes indicating the IAC is bad. My Vehicle speed sensor is not operational at the moment. The engine has run fine with out the VSS for thousands of miles.

Any help to solve my cyclical idle will be much appreciated.

Mine is a turbo but recently I fixed a very similar problem by cleaning the PCV and lines running to it. It solved the problem, although mine is the ej22t. so it may be un related. Never the less, I would recommend you start by cleaning both the PCV and IAC with Brake cleaner. carb cleaner etc...Also do a quick check for vacuum leaks!

What is the PCV and where is it on a '91 EJ22 NA?

i think your best bet is to pour carb cleaner down that iac hose. Do this running but you need to hold the throttle. Add bit by bit taping the throttle to cycle the valve. Then hook it up and see how it runs.

Pcv valve is on the intake manifold just behind the Throttle body, on the Passenger side, and it takes a 19mm closed wrench to pull it off. It has a hose leading nearly straight down into the block. Heres a random pic of one I found online, I would have taken one myself but My car was recently ransacked and they got my camera. heres the link--- http://subaru.fmgreen.net/PCV.jpg

The IAC valve should be make some sort of noise....like a humming sound. It shouldn't go away.

Like mentioned, check all the hoses and what not. I'd also suggest checking the wiring to the IAC valve.

Are you running the stock ECU?

The noise was definitely not normal. I said "was" as I think I solved the problem. I took off the solenoid on top of the IAC valve housing. Pushed the shaft (that goes into the housing) up and down while shooting carb cleaner into the air intake of the IAC.

This seems to have fixed the noise and cyclical idle. Though now, it idles high. Maybe when I slightly stretched the spring between the solenoid and IAC housing is causing the high idle. Otherwise I have no idea about why it is idling high and can't figure out how to adjust it manually with out touching the throttle stop screw.

Engine was recently rebuilt and vacuum hoses are new. I am addressing this high idle via a separate thread, but if you have ideas let me know.

Everything is stock, minus that fact the EJ22 engine is in a VW vanagon.