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Registered
Join Date: Jan 2003
Posts: 56
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bucking while driving
Hello Folks,
My 911 has been sitting on for a few months while the transmission was being rebuilt, clutch replacement and repairing a few oil leaks. Now that the car is back together, the car is bucking while driving. Mind you I had to lean out the mixture because black smoke was coming out at idle. I stopped leaning it out when the black smoke stopped coming out at idle. Now I can't tell if the mixture is too lean or too rich. Any helpful hints would be appreciated. 79 911sc targa nedzaldivar@yahoo.com |
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11-29-2003, 03:34 PM
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Registered
Join Date: May 2000
Location: Los Alamos, NM, USA
Posts: 6,044
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One can't correctly set the mixture without a CO gas meter. Either borrow a exhaust gas CO analyser or pay a shop to correctly set the mixture. Running too lean of course can eventually burn the valves. Cheers, Jim
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11-29-2003, 03:45 PM
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Guest
Posts: n/a
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It's more difficult with bucket seats........
Oh.....you said bucking......sorry, please disregard. 
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11-29-2003, 03:56 PM
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Senior Member
Join Date: Feb 2000
Location: Lacey, WA. USA
Posts: 25,308
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JW told me the other day that mixture adjustment on CIS cars only affects idle mixture. I thought about that, and the sensor plate, air volume, etc., and I believe John. My guess is you may have an air leak or plugged injector.
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Man of Carbon Fiber (stronger than steel) Mocha 1978 911SC. "Coco" |
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11-29-2003, 07:28 PM
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Registered
Join Date: Jun 2001
Location: Sweden
Posts: 5,911
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What kind of "bucking" are you talking about? If it's only mechanical bucking then it is porbably just worn CV's.
Try to drive straight at low speed, in high gear (so engine turns at only 900 RPM or so) and step and release your accellerator pedal. If it feels like your car is bucking between two hard stops then your CV's are probably worn out.
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Thank you for your time, |
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11-30-2003, 01:00 AM
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Registered
Join Date: Mar 1999
Location: Cornwall-on-Hudson, New York, USA
Posts: 4,499
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Not necesarily. My modified SC does it at low revs, no throttle, and has brand-new CVs.
Stephan
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Stephan Wilkinson '83 911SC Gold-Plated Porsche '04 replacement Boxster |
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11-30-2003, 06:48 AM
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Original Owner
Join Date: Dec 2002
Location: San Antonio, Texas
Posts: 1,907
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The mixture adjustment screw on CIS affects the entire range of operation except possibly WOT if the control plunger is full up.
Its only called "idle mixture adjusting screw" because you set it at idle. Where is Souk when needed?? Low RPM bucking when cold or hot or both?
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tsuter 78 911SC Turbo Targa Thaaaats Right!! Last edited by tsuter; 11-30-2003 at 07:29 AM.. |
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11-30-2003, 07:26 AM
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Registered
Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
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As far as I can tell, all SC's buck to at low r's to some degree. It's called Bonanza syndrome. Still no cure!
Joe |
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11-30-2003, 07:45 AM
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