Quote:
Originally Posted by PanzerSD
Semi-hypothetical questions.
In which position is an auxiliary air valve most prone to failure?
In the open position, or closed position?
Also, is it possible for said valve to fail to a point where it will function, that is the valve moves, but doesn't fully close? My cold idle is consistent with it's operation, but when it's warm, to achieve a decent idle speed, I need to choke the idle screw almost closed.
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Panzer - the AAV can stick in any position. It may move but not enough. The one on my car never seems to close when it should. But when I take it out and check it on the bench, it closes at 150F as it should. Only solution appears to be to give it a good cleaning - I have soaked mine in solvents, then in detergents, cycled it open and closed (using heat gun or hot water), then cleaned again. Have also crimped the bulb a little to get valve to fully close.
One of these days, I am going to replace the AAV with an electric one that I can operate from dash. gurunutkins posted a while back about such an upgrade. - Here is what he said:
Quote:
Originally Posted by Gurunutkins View Post
I like having a pressure gauge, not only can you check your pressure but if a rubber fuel hose breaks it lets you know if there is a sudden loss of pressure
The AAV or cold start air valve always remains open a tiny little bit as I remember but maybe a half a mm or so. I have 2 spares and am selling a 3rd on ebay right now so I just checked them in boiling water and the lip on the slider can only close up to the very last notch then it physically has to stop with maybe a 16th of an inch open at most. One of the functions of the megasquirt controller is that I can run a bosch 3 wire electric fast idle/ auxiliary air valve/ cold start air valve (so many names for the same thing) so I am running that conversion this winter along with my probable conversion to edis. I believe you can manually control a 3 wire bosch AAV ( I bought mine off a saab in the local scrap yard for $3.50) with a rheostat on the dash (I have seen it mentioned on some forums and will keep an eye open and copy you if I find it again) so that you can manually control the revs on cold start. Thats of course the other thing you could do is wire in a bosch 3 wire aav prior to the AAV on the car and set it to either on or off with a toggle switch, that way you could use your existing AAV for cold start and then once warm close the electric AAV which would seal the air flow to your existing AAV. cheaper than using a new solenoid valve
cheers
barri
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Graham
85 300D
,72 350SL, 98 E320, Outback 2.5