924Board.org

[pmcaya2]

I just completed a tune-up and timing on my 1982 924NA/US. Checked for vacuum leaks, etc. and it runs great, but it only idles at around 500 rpm.

Haynes shows an idle adjustment on the fuel distributor using a special tool to turn an adjustment on the upper left of the distributor as you face the engine. My fuel distributor has only 3 slotted screws at 12, 3, and 9 o'clock. The one at 12 o'clock has a milled line. I could simply turn it and see what happens, but I though I'd ask the forum first. Thanks in advance for comments. - Peter

[brian19600]

You use a t-handle hex wrench on it. (i think 3 or 4mm). There should be a rubber plug on a wire hook that you pull out to have access to the adjustment.
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78 924

[pmcaya2]

Thanks, but I have no such fixture on my Fuel distributor - only the 3 slotted screws as described.

[Rhubie]

I've seen what your talking about... BUT I think you should adjust your MAF so its a bit more higher. By doing this there will be more fuel given to the system allowing for higher idle. There is a screw that uses an Allen wrench. Make sure you keep track of your turns though so you can back track if need be because the engineering on the MAF can be confusing
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1980 Porsche 924 Weissach Commemorative Edition

[brian19600]

It's recessed below the the surface. So you are sticking the wrench down a hole. It's not actually on the distributor unit, but just behind it (toward windshield) between the distributor and the big rubber air intake hose. You may be missing the rubber plug, but there needs to be one there when you're done.
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78 924

[924-76]

[Eric P]

[Paul]

Same for the throttle stop screw, leave it alone.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[pmcaya2]

[img]https://www.flickr.com/photos/knightscreekphoto/36031905546/in/dateposted-public/[/img] (alt P)

Thanks all for the posts. I really didn't want to mess with the fuel distributor - car is running great. I simply found the set screw on the throttle linkage and turned it in a bit. I had to carefully remove the electrical fixture taking great care to not drop the 2 screws on the bracket. Used a 5/16th wrench to loosen the lock nut, then turned the screw in about 1 turn. Now the car idles at around 900 rpm. I hope the images come through and are useful to others. - Peter

[img]https://www.flickr.com/photos/knightscreekphoto/36072650515/in/dateposted-public/[/img]

[924-76]

That is the throttle stop screw, you should use the idle adjustment screw. It is located on the side of the throttle body and adjust with a flat screw driver.
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1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP

[pmcaya2]

Thanks 924-76 and others - I found the brass adjusting screw and will use it for additional adjustment. Peter

[pierro]

Could this be helpfull.......

Basic idle speed and mixture setting

Throttle stop screw setting; take a thin paper between screw and butterfly lever and position stop screw against the paper. Now turn stop screw ½ turn clockwise and block screw

If the idle speed and mixture adjustments have been totally screwed up. Start from scratch. close the idle speed all the way down, then turn it out two complete turns.

Start the engine, adjust the idle mixture so the car will at least run well enough so it will warm up. Don't leave the Allen wrench in the adjustment hole when you are checking the changes you have made. The weight of the wrench can influence the working of the throttle sensor plate. And don’t push down real hard for the same reason. The hole where the wrench goes in bleeds enough air to throw the mixture adjustment off slightly, so you are going to want to reinstall the plug when you are done, and make a final check.

After the engine is warmed up, check the ignition timing first. Then set the idle speed. Then adjust the idle mixture from rich to lean making note of the range in which the adjustment can be rotated and the engine speed does not fall off, or rise significantly. Then set the mixture adjustment to the centre of the range.

Check the idle speed. Is it correct?

If not, adjust the idle speed, then readjust the idle mixture adjustment to the centre of the range.
Now blip the throttle. Does the engine speed rise smoothly, or bog down? If it bogs down, the mixture is too lean, and you need to adjust the mixture a little richer. Not too much, an 1/8 of a turn at a time can make a difference. I use an axtra long allen wrench, and pay attention to the handle at the top to keep track of how much I have rotated the adjustment.

Now go to the back of the car and look at the exhaust pipe. Can you see the exhaust coming out? What color is it? Blue smoke at idle, sorry, you have a worn engine. Black smoke, still too rich for some reason. Did you wait for the engine to warm up before starting? How does it smell? Like overheated metal? Bad cat, or too lean, maybe a cracked exhaust manifold. Does it smell like gas? Again too rich.
After this check the CO2 level to be between 1 and 2 (1,5 is OK)

success,
Pierro
_________________
Porsche 924 1983restored
MG-Midget 1974 restored
Citroen 2CV 1986 restored
Rover Mini 1275 1992 restored
Mazda MX-5 1.8 for the fun
Toyota Lancruiser Prado daily driver
Merceds Benz W124 230E for the quality

[pmcaya2]

Thanks Pierro - It might be a good idea to repost yours and other comments in the "How to" section of this forum. Haynes was not helpful and I couldn't find any useful posts here on the topic. Thanks for the time you took to respond - my car is running better than ever. - Peter

[pierro]

I am glad it helped you out.
Found this write-up on the internet some time ago and saved it for the restauration project of my Porsche 924
Enjoy driving the Porsche...

Pierro
_________________
Porsche 924 1983restored
MG-Midget 1974 restored
Citroen 2CV 1986 restored
Rover Mini 1275 1992 restored
Mazda MX-5 1.8 for the fun
Toyota Lancruiser Prado daily driver
Merceds Benz W124 230E for the quality