AAV Testing?

[Scott R]

I read through the archives and I have the AAV sitting in my freezer right now to see of the gate opens. When I removed it from the car it was all but 10% closed.

Could I also hook this thing up to +12 and see what happens? It should close after a while correct?

Second question, anyone ever drill the rivits and try and repair this thing? Only reason I ask is that I have not seen these on Ebay, or in the for sale section.

[RarlyL8]

Why are you looking at this part (what's the problem)?

If you've seen the schematics you know the AAV is a simple bi-metal strip that opens the air passage when cold and closes when warmed either by ambient heat or electricity.
You can check it for cold start function by simply looking at the "1/4 moon" showing in the air passage.
Connect 12V and the gate should shut within a few minutes (time depending on ambient temperature).

[Scott R]

The gate never really shuts all the way on my AAV, it leave about 15% open at the end, this was after I had it out and hooked to a battery.

I'm looking at just about everything to help cure an inconsistent idle problem that I have. I have had three CO adjustments now, most recently because I did a valve job, and I still can't get the sucker to idle correctly.

First start the idle is low, and then it gets better. Then after driving for a while it sits around 1500RPM and never drops down. I had my wrench check the hot and cold pressures and they were supposedly correct.

All of the o-rings and one injector were replaced in this effort, all new intake runner boots, and new intake gaskets as well. So I am going part by part to figure out what is going on.

I do notice that on my 80 there are two large diaphragms on the passenger side, the very top diaphragm is disconnected, and if I apply vacuum to it the idle jumps to 3000K and stays there. (It was unplugged when I bought the car.) At the time of purchase it ran great no issues, even passed smog with flying colors, and now this issue.

I am down to a leaky injector at this point since everything else has been checked or replaced. Any ideas?

[RarlyL8]

Your AAV should close completely when the engine is warm.
To eliminate this "issue" simply bipass the AAV. If your car idles correctly you have found the problem. If not, leave the AAV blocked off and continue your search one component at a time. You can come back to the AAV after the idle problem is fixed.

Does the diaphragm run a vac line to the distributor? If so you could be advancing the timing under vacuum. Could also be the AAR. There are several different smog bits on the various engines produced that year. Do you have a schematic for your engine that identifies the components?

[Scott R]

With the AAV bypassed it runs like crap, so I guess I can move on from that, I did remove it and clean it however.
As far as identification, I have the factory service manuals, so no issues there.

Vacuum lines, well I have two of them on the distributor, one on the advance diaphram from the throttle body, and one to the back side of the distributor going to ported vacuum. If I remove the rear line (blue) the car starts to die. I can remove the red line (to the front advance diaphram) and it has no vacuum at idle. The FSM lacks detail in this department, is this system working correctly?

[Brother]

Originally posted by Scott R
The gate never really shuts all the way on my AAV, it leave about 15% open at the end, this was after I had it out and hooked to a battery.

I'm looking at just about everything to help cure an inconsistent idle problem that I have. I have had three CO adjustments now, most recently because I did a valve job, and I still can't get the sucker to idle correctly.

First start the idle is low, and then it gets better. Then after driving for a while it sits around 1500RPM and never drops down. I had my wrench check the hot and cold pressures and they were supposedly correct.

I have the same changing idle problem.

If your mixture was set with a valve that never closes fully, then it might be a little rich when you start up. See if it changes to normal when it warms up.

[Mysterytrain]

You guys are talking about the Aux air regulator [AAR] not the AAV, aux air valve. The valve gives you a gulp of air at start up, no electrical hook up, it closes with engine vacuum. The AAR on the other hand is a fancy replacement for the hand throttle. Ck out my old post......... which would have been easier to search for if I could spell!
http://forums.pelicanparts.com/showthread.php?threadid=200906

[RarlyL8]

The AAV described in the initial post does have an electrical connection that speeds closing of the valve after initial start up.
The AAR looks like a vacuum pot and has much smaller vac lines with no elecrical inervation.
Unfortunately I have seen the names of these devices interchanged on a few schematics.

[Mysterytrain]

All right lets set this straight once a for all!! This is the AAR Auxilary Air Regulator [the red guy in the picture]=>
http://www.pelicanparts.com/catalog/images/fuel_injection/new_images/fi_fielsystem_1-7-2g36.jpg

And that flying saucer thang is the AAV.

Come on Rarly you know better then that! a side note..hope you made out ok with the storm.

[Scott R]

Originally posted by Mysterytrain
All right lets set this straight once a for all!! This is the AAR Auxilary Air Regulator [the red guy in the picture]=>
http://www.pelicanparts.com/catalog/images/fuel_injection/new_images/fi_fielsystem_1-7-2g36.jpg

And that flying saucer thang is the AAV.

Come on Rarly you know better then that! a side note..hope you made out ok with the storm.

Why do I have two AAV's on my 80? And why when I add ported vacuum to top AAV do I get and instant 3000k idle?

[Mysterytrain]

Porsche got cute with the CIS system in the 80 sc one of those things is a decel valve. The 78/79 had a decel valve that was bell or pear shaped and sat behind the the throttle body..and was adjustable.

[Brother]

Holy Crap! A new AAR is nearly 700 bucks! When did that happen?

[Scott R]

Originally posted by Mysterytrain
Porsche got cute with the CIS system in the 80 sc one of those things is a decel valve. The 78/79 had a decel valve that was bell or pear shaped and sat behind the the throttle body..and was adjustable.

So what does the upper decel valve do? It was not connected to vacuum when I purchased the car, so I hooked it up and the idle jumped to 3000k and stayed there. So I have it disconnected, but I think it's trying to tell me that something else is wrong.

[ianc]

So what does the upper decel valve do?

There isn't an upper decel, there is only the decel valve. This is the flying saucer shaped thingie with the vacuum connection. It is supposed to slow the engine's mad dash for idle when you lift off the throttle suddenly to prevent a lot of unburnt gas from hitting the exhaust. Disconnecting the vacuum line from it will often make it shift easier, so people do. I did.

Under high manifold vacuum it allows more air to bypass the throttle to create a more combustible mixture until the engine slows to idle. If you're getting an increased idle when you connect it, the diaphragm inside it is probably leaking. Vacuum leak, in other words, and this could be the source of your problem. Remove it and check; it will difficult to set the idle like this.

ianc

Edit: Rarly was right: the AAR (Auxiliary Air Regulator) should be completely closed when warm. Air through it will still be metered by the sensor plate, so it will cause a high idle if still open. To check, if the engine of fully warm, pinch off a hose to it. If the idle drops, it either doesn't have current, or it needs replacing.

[Scott R]

Originally posted by ianc
There isn't an upper decel, there is only the decel valve. This is the flying saucer shaped thingie with the vacuum connection. It is supposed to slow the engine's mad dash for idle when you lift off the throttle suddenly to prevent a lot of unburnt gas from hitting the exhaust. Disconnecting the vacuum line from it will often make it shift easier, so people do. I did.

Under high manifold vacuum it allows more air to bypass the throttle to create a more combustible mixture until the engine slows to idle. If you're getting an increased idle when you connect it, the diaphragm inside it is probably leaking. Vacuum leak, in other words, and this could be the source of your problem. Remove it and check.

ianc

I swear I have two flying saucers, one right above the other, I'll try and get a pic. Each is identicle and each has a vacuum nipple. They are also both part of the same system, I remember this when I had the motor out and had to remove the hard line to replace the breather gasket.

[RarlyL8]

I stand by my comments.
The red guy in your picture is an AAV according to my Porsche factory shop manual. As I said before the names are transposed on many schematics. They are all Auxillary Air "Devices". Physically the two devices are very different so it is not so hard to describe them and make someone understand which part you are refering to.

Your decel valve may not have been functioning and was plugged by the PO. The result of a decel valve failure is that air permanently bipasses the throttle, and you guessed it, causes a high idle. (Although probably not 3,000,000 RPM) Ha!

No storm here in Northern AL. We now have displaced hurricane victims though.

[ianc]

I swear I have two flying saucers, one right above the other, I'll try and get a pic. Each is identicle and each has a vacuum nipple.

Yes, you're right, but the vacuum connection on the AAV (Auxiliary Air Valve is not really a vacuum connection; it is only a vent to the atmosphere, and shouldn't be hooked up to anything. The decel valve is the lower of the two and is easier to access. It is closest to the AAR.

ianc

[Scott R]

Yes, thank you! That has been bothering me since I purchased the car. Well I can now move on then and continue checking other areas.

[ianc]

Make sure the AAR is closing fully as I described above. Pinch off a hose to it when the engine's fully warmed up. If the idle drops to normal, you need to R&R that guy,

ianc

[Scott R]

Yea, it's not closing. I seem to have a host of CIS issues at this point, bad injectors, bad AAR, and who knows what else. I am so discouraged at this point, I mean I just dropped the damn motor to reseal and correct all of this, and of course more issues.