Seems to me I had this replaced maybe 20 years ago and now it’s failing to close completely again. Surely somebody out there has come up with a workaround. There are so many inexpensive electronic temp sensors, timers, solenoid air valves, etc available on eBay, that there must have been someone out there clever enough to have engineered something more elegant than a cable-operated butterfly. Before I embark on that journey myself, I’m hoping that clever someone might share their solution.

As promised, I experimented and think I have found a viable substitute for my AAV. I've done a write-up with photos for anyone who is interested. It can be found on my web site. https://bit.ly/41HMrJq

Hey, nice effort Dave, and a very good writeup with pics. Basically a manually controlled aux air valve operated by a toggle switch under the dash, all ripe and ready for further refinements.

You're reminding me here of how much time I used to spend on my '74 140 fiddling around with its newer AAV design. It seemed every other oil change that I felt the need for an inspection, cleaning and possible readjustment to achieve a more well behaved idle. I recall I replaced it once with a new (not at all cheap then for a a young owner like me and my first new car). I was then comfortable incracking open the old one to see in detail how it worked with the internal compound bar and shutter, now playing with it to make a good spare. I had the spare adjusted high and would occasionally swap it in when the engine was going through one of its rough idle periods trying to challenge my limited auto skills and technical abilities then.

These P1800 ones were quite different in design and operation. I hadn't known about them until now, more likely I forgot what I did know. Retrofitting the later ones to your engine was not overly trivial as I soon realized when spotting that kit on Skandix.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Thanks, as usual, for the clarification. I should have known that. Of course it's D-Jet.


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'79 242, '84 DL 2 door, '80 DL 2 door, '89 DL Wagon, '15 XC70 T6 AWD

Dumb question time.

How did you test the original part? I ask because you mentioned hot water testing a replacement part. Can we assume you used this same method on the original?

Is the AAV getting power? Excuse me for asking but you did not mention it so I have to wonder. You say it won't close completely but if it passed the hot water test then wouldn't the problem be electrical?

If you are wondering what's going on inside there are some pretty good pics of a gutted valve in this query from another DIY site. Please be informed, I am not suggesting this guys problem is your problem. His valve might be open or closed or somewhere in between on cold start. I only put this here for purposes of illustration. In fact, I am saving these pics for my own future reference.

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/522465-auxiliary-air-valve-inner-workngs-questions.html

You sound like a tinkerer. I thought maybe you would like to explore fixing the original before resorting to other methods.


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'79 242, '84 DL 2 door, '80 DL 2 door, '89 DL Wagon, '15 XC70 T6 AWD

The AAV for a D-jet 1800/140/164 is bolted to the side of the cylinder head and it has a bulb that is exposed to coolant and works it like a coolant thermostat, but in reverse as it closes when it get hot. The 164 AAV is different, but works the same.

Starting with the K-jet/CIS 140, Volvo/Bosch used an AAV with an electric heating element.

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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

With memories of those early idle air valves, I got curious.

If this is it, looks like Skandix may have their version of the mechanical air valve still available
https://www.skandix.de/en/spare-parts/engine/fuel-mixture-formation/injection-system/idle-control/idle-control-valve/1022926/

They also had a conversion kit that used the 140 ones I'm more familiar with. It's now listed as out of stock, but may be worth trying to contact them in case they can make up a kit on demand
https://www.skandix.de/en/spare-parts/engine/fuel-mixture-formation/injection-system/idle-control/idle-control-valve/1049063/

I don't imagine either option is as cheap as you had in mind. If someone knew how to fix them, Eric surely would have known.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

You're right, neither of those options is cheap. There was (is?) a guy selling these, rebuilt, on eBay for about $100. I got one and hot-water tested it. Can't remember why, but I sent it back and was graciously refunded. In any case, this is really a low-tech, unreliable device at best.

As Planetman noted, and my own experience with my AAV being completely disconnected has shown, the actual, practical warm-up period is not very long. Yet, should I have to leave the car outside for a protracted period in winter, I would like this option.

So, rooting around in my parts drawers I've found two items, both under $10, that I think I can combine to make a reasonable operational facsimile. One is a readily available 12V programmable digital thermostatic switch (Marlin P Jones P/N 32764-MP), the other an eBay 12V solenoid air/water valve. The T-stat device has a temperature probe that I can affix to the block and the valve would be inserted between the two existing air hoses. Using the temp switch to control the valve and playing around with its off/on temperature set points, I think I'll be able to get a good approximation of the performance of the original, lacking only the ramping function.

Will be playing around with this and report back with diagram and photos if it works. Meantime, keep those alternative suggestions coming. Always more than one way to skin a cat.

There's a NOS 1 on ebay for $525.00.

It's possible to rebuild 1.

We've installed a later AAV for 1974/1975 B20, but it wasn't very pretty.

We've plugged 1 of the AAV hoses and had the customer hold the idle up until it warms up which here in SoCal usually doesn't take very long.


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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com