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tj924 · Posted: Sun Aug 28, 2005 9:13 am Post subject: Yet another AAV question

I have had a cold start/initial rough running problem for a couple of months now & decided to pull & check my AAV yesterday. When "cold" (around 15C I'd guess) it was probably 90+% closed. I put it in the freezer for 6 hours & the hole was still 70+% closed (but it definitely does open up more)

I have seen other posts where people talk about cleaning & adjusting the AAV. I gather the adjustment is the little nut on the front of it, but how can I clean it?

I'm thinking of heating it up (hairdryer) &, assuming it closes all the way, adjusting it until it is just closed to see if I can get the hole any bigger when cold. Does that sound reasonable?
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TJ
Silver '82 924 NA 5-Speed Manual

Smoothie · Posted: Sun Aug 28, 2005 10:48 am Post subject:

My AAV is different, but by my understanding of the NA's AAV that nut isn't a direct adjustment of the opening - instead it locks the adjustment in place. To adjust, with the AAV fresh out of the freezer you'd loosen the nut and reach in with a screwdriver and push the valve open to where you want it, then tighten the nut again. That's how it would go in a perfect world anyway. Count on having to do it more than once. -And if you open it too far and need to close it some, I don't know...maybe drill a little detent in the valve plate so it can be pulled back the other way with a pick.
To clean, just spray some carb cleaner in there, shake it around, let it drain.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Lizard · Posted: Sun Aug 28, 2005 10:53 am Post subject:

I dont think that cold starting would be an issue for you down under
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3 928s,

tj924 · Posted: Sun Aug 28, 2005 11:28 am Post subject:

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

Update on AAV adjustment.

I've tried a couple of times to adjust a spare AAV I've got, like it says in the Alfa GTV website, but it never seems to work.

I loosen off the nut; no problem, move the disc one way or the other ; no sweat, then tighten the nut with the disc in the 'right' place and it always springs back to where it was to start with.

I've tried both AAVs on the car and there is no difference in the way the engine behaves, so I've given up trying.

At around 15°C, you should be able to see about a 2 - 3 mm square hole in the disc, at over 40 - 50 °C (engine running temp.) the hole closes completely. If you cool it down to about 0°C (freezing, so this shouldn't be a problem in your case, tj!), you see a roughtly-triangular opening about 1/3 the area of the disc.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

tj924 · Posted: Tue Aug 30, 2005 5:56 pm Post subject:

timstar92404 · Joined: 22 Sep 2004 Posts: 2075 Location: richmond BC

I have the same cold and hot start problem. idles too lough and less power when starting from cold engine.

my aav also seems to function. opens up about 70 percent or so after one hour in the freezer.
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78 924 sold.
85.5 944

Smoothie · Posted: Wed Aug 31, 2005 2:10 am Post subject:

Two more thoughts on adjusting the NA AAV - If it can be disassembled by removing the black plastic end where the electrical connector is, I think you should find the bi-metal strip attached. Once it's out, it could be bent one way or the other to adjust the valves' opening.
-or-
If the black plastic end can be turned (and again, the bi-metal strip is attached to it), then some adjustment should be possible by simply turning it.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

Good thinking, Smoothie.

I don't think the plastic connector can be turned, because it's retangular in cross-section, but it may be possible, with the right amount of judicious force, to remove it and get at the bi-metallic strip from that end.

I don't think it's worth it in my case. I've come to the same conclusion as tj924, that my AAVs (one on the car and the spare) are both working as intended.

However, I'd still like a few more revs in the colder weather and I think the easiest way to get this is to enlarge the hole in the disc, say with a drill if I can get in there. Now I've got the spare AAV, if I trash it I can still use the car.

Tim and TJ: it sounds to me like you've both got WUR problems.

_________________
1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org