924Board.org

Meneer aard · Joined: 27 Jan 2006 Posts: 73 Location: Netherlands

When i start my car cold, the engine runs arrount 600 rpm. When i drive it for a minute the idle speed is climbing to 1100 rpm and when the engine is hot 1000 rpm. If the car is hot, and i start it, the engine runs 1000 rpm fine. Its only when the engine is cold.

I think the Air Auxilery valve is durty or lack of grease? Because i think the valve is stuck arround some point, when the engine is hot the valve is closed. When the temperature is dropping, the valve open's (bi-metal). So i think its stuck in that position (closed) and when the engine lightly warms up (after 1 minute of driving) the valve warms uo to, and it releasing it self from the closed postition to the open position. (hot metal expand, cold metal schrink).

Could it also be the vauum hoses? Or with wich type of cleaner/ grease or something should i clean the valve. My thought: Clean it with brakecleaner and after cleaner a bit of wd-40?

Thanks in advice:)
_________________
Porsche 924 Euro 1977

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Try a bit of throttle body cleaner, also electrical parts cleaner for the plug.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Ozzie · Posted: Tue Nov 07, 2006 11:17 am Post subject:

The aav is open when the engine is cold and closes when hot.

If it is jammed shut it will work the way you describe.
Easiest way to check is remove it and put it in the freezer.
Or outside if it is real cold.
Another problem could be your WUR or even your vacumm lines.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Tigger937 · Posted: Tue Nov 07, 2006 12:49 pm Post subject:

Greetz, Smoothie has an excellent post regarding the adjustment of the AAV complete with photos if that is your problem. Do a search. BOL.
_________________
1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

Smoothie · Posted: Tue Nov 07, 2006 4:12 pm Post subject:

Here's the link to the 931's AAV adjustment -
http://www.924board.org/viewtopic.php?t=13357&postdays=0&postorder=asc&start=24
-and 2 posts down from that, a link to a procedure for the 924NA's AAV -
http://www.924board.org/viewtopic.php?t=13357&postdays=0&postorder=asc&start=26

_________________
"..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

Meneer aard · Joined: 27 Jan 2006 Posts: 73 Location: Netherlands

The problems with the AAV are back

After cleaning the AAV a couple of times, it worked @ the first 10 seconds. When i start the car, it runs great @ 1000 rpm, but after 10-15 seconds it drops to 600

After driving it (1 minute) its runs again @ 1000 rpm and keeps running fine @ 1000 rpm.

But only when cold the car idle is @ 600, with my foot on the accelerator it keeps running smootly @ 1000 rpm..But when i break or something (no foot on the accelerator) it drops back to 600.

Anybody an idea? Is the idle adjustment the problem?
_________________
Porsche 924 Euro 1977

Smoothie · Posted: Wed Mar 28, 2007 4:38 am Post subject:

Did you try adjusting it [the AAV]?
Apparently your idle is set about right - to the high side, but within spec..
The AAV might have just gone a bit out of adjustment over the years. -But what you have, doesn't sound like a real serious problem. You might try the adjustment procedure if you're adventurous, or just leave it as-is and let it warm-up the minute before driving. A 1.25 minute warm-up to get to a steady 1000 rpm idle isn't bad at all. I think I'd leave it the way it is actually.
_________________
"..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

Meneer aard · Joined: 27 Jan 2006 Posts: 73 Location: Netherlands

Thanks Smoothie!

It`s not a serious problem, but 600 rpm for the engine when cold is a bit bad? (oil cold etc.).
_________________
Porsche 924 Euro 1977

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

Sounds very much like the AAV, but just make sure there isn't a slight vacuum leak.

I tried adjusting the AAV on my car and didn't really get very far. It always seems to return to the old adjustment

. Try a dose of WD-40; failing that, used ones are available on E-bay quite cheap.

Running at 600 rpm idle isn't a problem so long as the engine doesn't stall. It won't do any harm if you blip the throttle once in a while to get the oil and water moving.
_________________
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