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Tachometer Bouncing
Yesterday my tachometer starting bouncing around in the 930. It will be fine for a while then suddenly bounce from 2K-6K-1K-4K ect. It then stops for a while and may start again. Any ideas of what may cause this?
Thanks R
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Past: 04 Anniversary 911 #0895, 82 911 SC, 88 Signature Series Carrera, 88 911 Turbo Cab, 73 911T, 63 356B, 06 Cayenne |
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02-14-2006, 10:14 AM
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Join Date: Aug 2004
Location: NYC
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Does this happen while driving or while your sitting at idle? Does any of the lights come on when this happens?
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02-14-2006, 10:15 AM
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I have only noticed it while driving. No lights come on.
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Past: 04 Anniversary 911 #0895, 82 911 SC, 88 Signature Series Carrera, 88 911 Turbo Cab, 73 911T, 63 356B, 06 Cayenne |
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02-14-2006, 10:23 AM
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Slackerous Maximus
Join Date: Apr 2005
Location: Columbus, OH
Posts: 18,169
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Bad voltage regulator. Classic symptom.
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2022 Royal Enfield Interceptor. 2012 Harley Davidson Road King 2014 Triumph Bonneville T100. 2014 Cayman S, PDK. Mercedes E350 family truckster. |
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02-14-2006, 10:24 AM
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Join Date: Mar 2004
Location: North Jersey
Posts: 416
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Don't rule out a bad ground to the tach.
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Howard '76 911S '53 Nash (!) '01 Audi TT '82 GPZ-550 |
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02-14-2006, 10:38 AM
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Join Date: Jun 2002
Location: PNW
Posts: 2,753
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I second voltage regulator and add alternator failing.
I had the same symptoms, replaced the regulator only to have the alternator die two days later.
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gary |
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02-14-2006, 10:51 AM
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Join Date: Jul 2003
Location: Back in B'ham, AL
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Time to change/rebuild the alternator...
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02-14-2006, 11:14 AM
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Join Date: Apr 2005
Location: outta here
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Rig up a voltmeter to some handy place, like the cigarette lighter circuit, and take a drive. Have someone observe the voltage when the tach acts up. If the voltage goes up when the tach acts up, you will have confirmed a voltage regulation problem, as others have observed.
JR Last edited by javadog; 02-14-2006 at 01:31 PM.. |
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02-14-2006, 11:41 AM
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Join Date: Dec 2004
Location: Halifax, NS
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Same problem with my 930 two years ago...bouncy tach. Checked grounding, all OK.
Shop checked voltage regulator, and replaced. No bounces for last two years. |
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02-14-2006, 12:19 PM
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Join Date: Jul 2005
Location: Somerville, New Jersey
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I had this happen after I changed out dash lights...bumped wiring loose while I was in there. I would check those connections first.
edit: those= those on the back of the tach
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02-14-2006, 12:19 PM
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Join Date: Aug 2005
Location: redwood shores Ca.
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Be careful....if the alt is over charging the battery will fry. If you start to smell sulfur or for us bay area folks a bay mud smell then water in the battery is cooking and could explode, or the smell could just make you sick. This happened to my carrera the battery was so hot that a meltdown was in process. Turn your lights on and see if they seem to be brighter another prob. can be radio static noise coming from you speakers when the radio is off.
check your system as soon as possible |
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02-14-2006, 02:19 PM
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voltage regulator..older cars like mine with ignition points will do it too when they get dirty or begin to close..but in your 930? VR..
ditto..get it fixed pronto.. ryan
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To the memory of Warren Hall (Early S Man), 1950 - 2008 www.friendsofwarren.com 1990 964 C4 Cabriolet (current) 1974 911 2.7 Coupe w/sunroof 9114102267 (sold) 1974 914 2.0 (sold) |
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02-14-2006, 02:48 PM
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73, 82, 88 Porsche 911 2.4, 3.0, 3.2
1974 Porsche 911 2.7
