Aux Air Control Question

[billb]

When the car is cold, should I be able to easily blow through the inlet tube to the aux air control valve? Of course the outlet tube that goes into the top of the throttle body is disconnected when I do this. Should I be able to feel a lot of air going through it and feel it coming out on the outlet side? Mine seems very restricted.

Also, when I pull the inlet tube off of the main air intake (when cold of course), the engine keeps running. I expected the car to stall because the MAF would not be measuring the air when the inlet is disconnected. Again, it seems to be sucking very little air. Very restricted. Could this valve be bad?

I hope you guys can understand this question. Hopefully I'll get some serious responses.

[oab_au]

Yes you should be able to blow through the Aux Air valve, as long as you don't turn on the key on. If you start blowing with the engine cold, then turn the key on(don't start just the key on) you will find that the valve will heat up and close the valve.If the key has been on befor you start, the valve will still be closed till it cools down.

I don't think the MAF is used at idle, I think it just uses the map settings. Should die if the throttle is opened.

Harvey.

[billb]

Thanks for the reply. With the car cold and key off, I have to blow really hard to get any air through this valve. Could it be bad?

I'm kind of focused on this valve right now as the culprit for my intermittent stalling problem. (The car will usually want to stall if you drive it til warm, turn it off for 1 or 2 hours, then restart it. It will restart fine but have difficulty running/idling). I've tried spraying cleaner through it. When I spray into the outlet tube, very little comes out the inlet side. I think it's plugged.

[comp_jas]

I'm not real familiar with the SVX AAV but most AAV's I've seen are open when cold to provide additional air during "cold" starts since the ECU is richening the air /fuel mixture.

They usually are either controlled by the ecu or have a bi-metallic spring which is heated (sometimes by the block). As the the engine warms the valve closes.

[billb]

That's about how I thought it worked. On the SVX, I believe it's a bimetal spring. After sitting for 2 hours, should it be wide open? Maybe partially open? And how wide open is wide open? I expected to be able to easily blow through it and feel lots of air coming through to the outlet.

[comp_jas]

I'd be a little surprised if the SVX only used a bi-metallic spring. I've only had my '97 for a year (knock on wood) w/o any problems.

My AAV experience is with BMW and Audi (lots of problems). Both used 12v (either direct or modulated) to a coil to move the AAV (the BMW used the block also).

Does the AAV have an electrical connector? If so the ECU or an Idle control module probably drives a solenoid in the AAV. You might be able rig up a 9v transistor battery to see if that moves it. I imagine its just a two pin connector.

[billb]

Yes. It has an electrical connector. I don't remember how many wires it has.
I'm pretty sure there's an ECU error code for it too. But, of course, I have no error codes, just a intermittent stall after startup.

[oab_au]

Originally Posted by billb

Yes. It has an electrical connector. I don't remember how many wires it has.
I'm pretty sure there's an ECU error code for it too. But, of course, I have no error codes, just a intermittent stall after startup.

This valve is operated by an electrically heated bi-metal strip, and by the conducted heat from the engine block. It would only take 60 sec. at the most for it to heat up and open.
When you start the engine, the Aux Air valve will will bring the engine speed to about 1500 rpms, this then stages down to 600 rpms as it closes and the By-pass air valve takes over. so if you have stalling after this time, it is not the Aux Air valve. More likely the By-pass Air Control valve, that sets the idle speed, is sticking.
There is no code for the Aux Air Valve, the Bi-pass Air Valve sets a code 24.

Harvey.

[billb]

Originally Posted by oab_au

This valve is operated by an electrically heated bi-metal strip, and by the conducted heat from the engine block. It would only take 60 sec. at the most for it to heat up and open.


Harvey.

You mean heat up and close, right?

After the car sits for two hours, would you expect the valve to be open? Yesterday, it wouldn't run at all after sitting two hours. It would start and die, restart and die....until after about 2 minutes of this, its fine.

No codes.

If the car warms up, the idle speed settles at 610rpm and the car will run perfectly. This problem (if its going to occur) will only occur during the warmup period.

[oab_au]

Originally Posted by billb

You mean heat up and close, right?

After the car sits for two hours, would you expect the valve to be open? Yesterday, it wouldn't run at all after sitting two hours. It would start and die, restart and die....until after about 2 minutes of this, its fine.

No codes.

If the car warms up, the idle speed settles at 610rpm and the car will run perfectly. This problem (if its going to occur) will only occur during the warmup period.

Yes Bill, my bad. I ment close.
The heat is maintained by the engine block, so it will not cool down very quickly. If it is the Aux Air valve, it should start ok if you hold the throttle open a bit. That will do the same job.

Harvey,