Itinerant Air-Cooled

So lots of us seem to have cold/hot idle issues associated with our axillary air regulators (AAR). I scored one at the Pick-n-Pull recently to trouble shoot the one currently on the bus. Since I had to test it prior to install, I figured I'd document for the community.

The AAR functions, to my novice brain, much like a choke. It provides some extra air to the ignition system when the bus is cold to increase the idle so you don't have to fiddle with the gas pedal while the engine gets up to operating temp. When it's not functioning correctly, you can get either a low idol (the AAR aperture is not opening) or a high idle after things get warmed up (the AAR is not closing).

Location of the AAR is in front of the oil breather and behind the right rear intake shown below. The little rubber elbow on the right is an often overlooked vacuum leak source.
[albumimg]2750[/albumimg]

Here's a side view of a cleaned up AAR (note the yellow crap on the little bolt--that's factory adjusted and also the location of the bolt to adjust your AAR if necessary):
[albumimg]2753[/albumimg]

Here's a photo showing the aperture open in the middle of the AAR. Note part number. The aperture was open at ambient temps this morning of around 55*. Perfect.
[albumimg]2751[/albumimg]

Here's a (bad) photo showing the aperture closed after sitting in a hot (250*) BBQ (flame off) for 10 minutes. There is the smallest needle hole still there but it's acceptable in my book.
[albumimg]2752[/albumimg]

The third test is for resistance. You want around 30 ohms. Hook up your meter thusly:
[albumimg]2748[/albumimg]
Read said meter:
[albumimg]2749[/albumimg]

Install the tested AAR. Run the bus around until it's at operating temp then adjust your idle to spec. Next time you start on a cold morning, your AAR should adjust your idle up and then back down to spec.

Ritter,

Thanks ~ my AAR was not working (diagnosed by IAC master) but we didn't have time to get to it. I mean to pull it this week and see if it's stuck, and if so, whether it's repairable.

Any thoughts on the latter? Does it come apart for cleaning, etc. or does it remain closed the better to protect the thermo switch, or whatever it is that makes the thing work?

Lanval

Thanks Ritter, I'll try that and see what happens.

If it doesn't... next stop, junkyard!

Lanval

I checked that my AAR works correctly (it does), and then gave my engine a little more cold idle speed by loosening the painted nut and adjusting it.

My cold start idle is now quite nice, but I still get a too-low idle after about 4 minutes of gentle driving after a cold start.

I wonder if the lack of a thermostat it keeping the engine cold for too long after the AAR has already closed.

I put on a functioning thermostat last summer while Colin was here. It really does make a big difference in warm up times. Now that my AAR is working correctly (a wiring issue, not the valve) and I have a functioning thermo, my warm ups are sounding pretty good.

It would seem mine was a similar case.

I left the AAR in the back of the van above the engine compartment, and waited till mid-afternoon on a day where the ambient temps were in excess of 100 degrees.

When I pulled it out, there was a tiny little hole that gradually got bigger as I cleaned it with carb cleaner. The hole was fairly large by the time I was done.

Resistance checked out at 30.6 ohms, and so I stuck it in and started things up. Upon start up the AAR was drawing a pretty substantial vacuum, enough to pull my lips to the rubber pipe and seal it.

Since the AAR is clearly working, I will assume it is the connector which is broken nearly exactly as Ritter's is. Zip tie will be the fix until I find out what the situation is with replacing broken connectors....

hints in that department?

Lanval wrote:hints in that department?

http://www.rs-autosport.net/catalog/pro ... cts_id=189

Depending on your skill/comfort level, you can either buy the type that you crimp on the wire yourself or the already-crimped type that you splice into the existing wires.

Here is a photo on adjusting the idle speed (this is in a FI beetle though)....

Randy in Maine wrote:Here is a photo on adjusting the idle speed (this is in a FI beetle though)....

So, clockwise winds the disk towards more open?
Sorry I did not get up to Maine.
Colin

Amskeptic wrote:
So, clockwise winds the disk towards more open?
Sorry I did not get up to Maine.

Colin

I think that is how it works. I am going to try it on my bus here shortly.

That is OK Colin. The leaves are tuning and few things out there really beat fall in New England. Give me a call when you are in the neighborhood. I will be here. I am doing to 25 to life here at the beach, so I am not going anywhere.

Hi Ya'll! Just wanted to revive this somewhat older post for a question to the community. Should the AAR be able to hold a vacuum when closed? I pulled mine off today after running and idling Odyssa (my 82 Westy) for 30 minutes or so. The valve gate was completely closed but when I sucked on the intake air plenum side I was able to pull some air through around the valve gate. Is this acceptable or should closed be like LOCK DOWN, can't get any air through here intake, go through the throttle!!

Tim always trying to learn

I have never cared enough to test one's vacuum-holding ability. The important part is they flow lots of air when cold, and not a lot of air once the bimetallic spring has warmed up. I don't think they're designed to seal 100%.

I was going to make some 'splaining, but I'd rather ask you to draw conclusions instead:
Does this small airflow when warm create a vacuum leak? Why or why not?

Robbie

asiab3 wrote: I was going to make some 'splaining, but I'd rather ask you to draw conclusions instead:
Does this small airflow when warm create a vacuum leak? Why or why not?
Robbie

I know, I know, I know, ask me pleeeeze.

Um, um well this small air flow when warm does not create a vacuum leak, because, um, because it doesn't.
Colin
(already metered air)

Thanks, MountainPrana.

Robbie

Amskeptic wrote:I know, I know, I know, ask me pleeeeze.

Um, um well this small air flow when warm does not create a vacuum leak, because, um, because it doesn't.
Colin
(already metered air)

asiab3 wrote:Thanks, MountainPrana.

Robbie

=D> bhahahahaha, ya'll crack me up. So as long as there is a big enough difference between open and closed so that it will slow the idle when warm and closed is the main concern right? It's basically a mini throttle controlled by it's own little heater instead of my foot, eh?

Tim still hunting for my idle issues