924Board.org

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

I have asked this question a couple of months ago but now I am getting serious because it is warm enough to actually investigate the problem. The problem is that my 1978 924 idles at 2000 RPM when the car warms up. I will check the vacuum lines and rubber hose connections. Can I replace the old plastic and cloth covered lines with new lines I bought from Lindsey racing for my 944. Is there anything else I should check for high idle.
Thanks
_________________
1978 924
1987 944

!tom · Posted: Fri Apr 05, 2013 1:13 pm Post subject:

AAV
WUR
_________________
78 924 NA
5-lug

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

Bypass screw
Throttle stop
Throttle linkage
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Ozzie · Posted: Sat Apr 06, 2013 7:12 am Post subject:

Check the timing, too much advance will cause this as well.
Sounds like a vacuum leak or faulty AAV
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

What is the fix for the AAV, take off and clean or replace.
_________________
1978 924
1987 944

Ozzie · Posted: Sat Apr 06, 2013 5:43 pm Post subject:

It usually is full of crud.
give a good wash and clean inside and when dry put in the fridge to test.
it should be open when cold and closed when hot.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

I removed and cleaned the AAV. The Haynes manual says to apply 24 volts to it for 5 minutes to see if it closes. Is there a positive and negative connection or can I rig two wires from a battery into the two terminals on the AAV without regard to polarity.
Question 2, where is the WUR on a 1978 924.
_________________
1978 924
1987 944

!tom · Posted: Wed Apr 10, 2013 3:09 pm Post subject:

Polarity won't matter; it's just a heater element.

The WUR is in a very awkward place, sort of on the firewall side of the intake manifold, kind of under the brake master cylinder.
_________________
78 924 NA
5-lug

staticsan · Joined: 19 Jan 2009 Posts: 450 Location: Sydney, Australia

I would've said the WUR was "under the coil". Difficult to get to but inordinately difficult.

Now the oil-sender - that's in a very awkward place!

Wade.
_________________
'82 British NA - Which I think I've been very lucky with!

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

I started the car and let it warm up. I then removed the hose coming out of the AAV. The car started to die so I immediately plugged the hose with a dowel and the car continued to run but the idle was still too high. So I am assuming the AAV is not the problem. Could the WUR be causing the high idle after warm up. Is there an article somewhere how to remove and clean the WUR. Any assistance will be appreciated.
_________________
1978 924
1987 944

!tom · Posted: Sun Apr 21, 2013 1:50 am Post subject:

Removing either hose from the AAV will introduce a vacuum leak in your system, which will cause poor running. You would have to plug both hoses, one in either end of the AAV in order to remove it from your system.

The AAV does not seal when closed.
_________________
78 924 NA
5-lug

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

tom, I don,t see how removing the hose on the intake side of the AAV would cause a vacuum leak. I am not saying you are wrong, I just don,t see how it could. I will plug both hoses connected to the AAV tomorrow and see if that brings my idle down. Thanks for the help.
_________________
1978 924
1987 944

Mudd · Joined: 27 Aug 2012 Posts: 78 Location: Cincinnati,Ohio

Do I have an Oxygen sensor on my 1978 na. If so could a bad Oxygen sensor cause a high idle after warm up.
_________________
1978 924
1987 944

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Throttle body leaking around the bushings? Try spraying a little carb cleaner or ether around the various vacuum lines and throttle body and see if the engine speeds up. Just be careful of electrical connectors and the exhaust side of the engine.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

!tom · Posted: Mon Apr 22, 2013 5:42 am Post subject: