924Board.org

GP924 · Joined: 16 Jan 2006 Posts: 34 Location: Grants Pass, OR

I am having problem wiht my idle. If I hold my intake open slightly at the fuel distribution unit the engine idles great but if I release the plat it closes and the engine begins to run rough due to the rich fuel mixture. It runs great at spead just won't idle. I can't find anything in my manual on how to adjust this (using a 1976-80 Haynes manual).

Anyone know how to adjust this.

Also is the 1976-1982 Haynes manual better for information on the 931? Is the clymer manual better for the 931?

This is frustrating as I cannot drive on the road until this is fixed. I really appreciate everyone's assistance in advance.

Grants Pass 924
Grants Pass, Oregon

Paul · Posted: Mon Mar 05, 2007 12:51 pm Post subject:

The Haynes manual is a good manual for your 80 931.

Most of the time, the issue your car is having is caused by vacuum leaks, check everything.
_________________
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.

GP924 · Joined: 16 Jan 2006 Posts: 34 Location: Grants Pass, OR

Thanks. You know when your close to the issue, you overlook the obvious. It will take me a while to trace each hose but it seems that there are really only two that could cause an issue of this nature (the one to the turbo and the one that comes off and goes for everything else attached for vacuum (passes under the air cleaner).

I will update once I find the problem, or if this is not the issue.

Thanks,

Al

Paul · Posted: Tue Mar 06, 2007 10:41 am Post subject:

Actually any vacuum leak past the air meter will contribute to this problem. If the air is not measured by the air meter, no fuel will be added for the air that's leaking in.
_________________
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.

der uber · Joined: 23 Feb 2007 Posts: 18 Location: Louisville, KY

If I may piggie back a related question...

Would a very small vacuum leak become more noticable under hard accelleration?

Sometimes when I push around 3500-4000rpm I get a small but noticeable power loss but everything fires. Seems like the fuel cuts back some. But it otherwise rides great - it is just when I "get on it." and doesn't always do it.

Everything I have read so far is all about vacuum.
_________________
1980 931 converted to n/a
My first project

924guy · Posted: Wed Mar 14, 2007 5:19 am Post subject:

clymer manuals for the 924 arent very good, though for some reason, they demand a premium..haynes is much, much better....
_________________
Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

Smoothie · Posted: Wed Mar 14, 2007 5:24 am Post subject: Re: vacuum leak or fuel delivery?

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

Malfunctioning wastegate or clogged control line could also cause this.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

der uber · Joined: 23 Feb 2007 Posts: 18 Location: Louisville, KY

The car is all turbo except for one small part - the engine - the PO rebuilt it as an n/a aroun 1989. Does that change anytihng?
_________________
1980 931 converted to n/a
My first project

Smoothie · Posted: Wed Mar 14, 2007 5:59 am Post subject:

Yes of course that changes everything. Repost your question in General Discussions and don't forget to mention whatever else the po changed that might affect the engine. Add to your profile the fact that it's no longer a turbo engine.
_________________
"..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

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

_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

der uber · Joined: 23 Feb 2007 Posts: 18 Location: Louisville, KY

Will do - my bad.
_________________
1980 931 converted to n/a
My first project

Smoothie · Posted: Wed Mar 14, 2007 6:57 am Post subject:

Very well. I was going to also tell you to leave your keys with your mother and go to your room, but you seem to have learned your lesson so there'll be no further punishment.

_________________
"..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

Silverarrow · Joined: 09 Nov 2002 Posts: 23 Location: Ames, IA

GP924 I just got done with a similar issue. Have you looked at the boot under the fuel distrib/flow meter? My water pump pully wore a hole in the boot due to misalignment. I had to take it apart and patch the hole with Shoo Goo. Any other leak on the intake track will do the same thing. Hoses are always going but they are obvious. The boot is hard to see and you have to sight along the waterpump belt track to see it. Just my two cents!
_________________
1977 924 NA no sunroof
1980 931 With a sunroof
I could be crazy, Oh yes I could!

GP924 · Joined: 16 Jan 2006 Posts: 34 Location: Grants Pass, OR

Is it possible to remove the turbo, exhaust and intake and install the intake and exhaust from a 924 on a 931? I have become so frustrated with trying to get my 931 to run correctly I am ready to give up on the turbo and just run it without. I know that probably sounds bad but better a running and driveable 924 than a junked 931.

Your comments appreciated.

Al in Grants Pass, OR