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coldwarvet

Joined: 13 Jun 2014 Posts: 51 Location: near sandy oregon
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Posted: Sat Jun 28, 2014 5:01 am Post subject: 931 stalls when mixture setting hole uncovered... |
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idles normal, good throttle response, goes like a scalded cat...would just like to set the mixture while it is running...can find absolutely no vacuum leaks, throttle plate centered and where it's supposed to be...I guess most who are familiar with these cars would say "leave it alone"...rather puzzling is all...control pressure maybe?
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1980 931 roadster, locking snail shell
forced-air intercooled
crane cams fireball turbo ign
boost control
Tial wastegate
water/alcohol injection
1986 dodge conquest TSI , 14B/12A hybrid turbo, Innovate
1986 E/P 944
!983 Ferrari euro-spec gray mkt 316hp gtsi quattrovalvole |
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Rasta Monsta

Joined: 12 Jul 2006 Posts: 11733 Location: PacNW
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Posted: Sat Jun 28, 2014 5:17 am Post subject: |
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plug out creates vacuum leak. . .
but i am always an advocate of testing pressures _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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Fasteddie313

Joined: 29 Sep 2013 Posts: 2595 Location: MI
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Posted: Sat Jun 28, 2014 10:31 am Post subject: |
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oh... good to know...
my car never had that plug since I bought it.. better make one up _________________ 80 Turbo - Slightly Modified |
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coldwarvet

Joined: 13 Jun 2014 Posts: 51 Location: near sandy oregon
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Posted: Sat Jun 28, 2014 11:33 am Post subject: |
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| I've always been of the impression these engines should run with the plug out...and very close to where they should be mixture-wise... |
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Fasteddie313

Joined: 29 Sep 2013 Posts: 2595 Location: MI
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Posted: Sat Jun 28, 2014 11:55 am Post subject: |
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mine runs.. I don't know how well yet though.. _________________ 80 Turbo - Slightly Modified |
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Carrera RSR

Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK
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Posted: Sat Jun 28, 2014 6:00 pm Post subject: |
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The removeable screw must be in place to allow the car to run without vacuum leak. The plastic bung on top of the screw is just to stop dirt and grime accumulating or screw rusting tight. _________________ 1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252 |
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Fasteddie313

Joined: 29 Sep 2013 Posts: 2595 Location: MI
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Posted: Sun Jun 29, 2014 7:02 am Post subject: |
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so I need a screw and a plug...
I shall examine it _________________ 80 Turbo - Slightly Modified |
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Paul

Joined: 02 Nov 2002 Posts: 9491 Location: Southeast Wisconsin
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Posted: Sun Jun 29, 2014 12:43 pm Post subject: Re: 931 stalls when mixture setting hole uncovered... |
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| coldwarvet wrote: | idles normal, good throttle response, goes like a scalded cat...would just like to set the mixture while it is running...can find absolutely no vacuum leaks, throttle plate centered and where it's supposed to be...I guess most who are familiar with these cars would say "leave it alone"...rather puzzling is all...control pressure maybe?
_______________________
1980 931 roadster, locking snail shell
forced-air intercooled
crane cams fireball turbo ign
boost control
Tial wastegate
water/alcohol injection
1986 dodge conquest TSI , 14B/12A hybrid turbo, Innovate
1986 E/P 944
!983 Ferrari euro-spec gray mkt 316hp gtsi quattrovalvole |
If it's not broke, don't fix it. _________________ 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. |
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Carrera RSR

Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK
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Posted: Sun Jun 29, 2014 6:49 pm Post subject: |
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It will never run right without the screw in the hole. It has a vacuum leak. Put your finger in the hole to hear the difference. If you can't hear the difference your engines not running well in the first place. _________________ 1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252 |
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