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#1
05-31-2008, 07:13 PM
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Bouncing tach needle
The tach needle on the Z starts to go crazy at 6000 RPM or so... and bounces around from pegged to 3500 then when you get out of it the needle falls back to normal. Is it the points bouncing and causing the tach problem or is it electrical?
__________________
~JAG~ NCRS#65120 68 GTO HO 4 spd Alpine Blue /Parchment 2 owner car #21783 71 Corvette LT1 45k miles Orig paint - Brandshatch Green - National Top Flight - last known 71 LT1 built. 71 Corvette LT1 42k miles Original paint - Black - black leather - only black LT1 known to exist. NUMEROUS Lemans blue Camaros, Monza Red and Daytona Yellow Corvettes & a Chevelle or two... Survivors, restored cars, & other photos https://picasaweb.google.com/lh/myphotos 
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#3
06-01-2008, 02:51 AM
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Re: Bouncing tach needle
I had a similar problem years ago and it was a bad connecting rod.
Good news: the tach needle stopped bouncing.  Bad news: the rod went through the block.  I would say bad ground for the dash/gauge or check the terminal end on the coil to see if it the copper wires are all broken except of a couple strands left. You may want to cut and recrimp the terminal end that mounts on the coil.
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#4
06-01-2008, 04:12 AM
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Re: Bouncing tach needle
[ QUOTE ]
I had a similar problem years ago and it was a bad connecting rod. Good news: the tach needle stopped bouncing. Bad news: the rod went through the block. Remind me to never let you drive one of my cars!   I agree with Steve that it's a connection that's causing the problem. Interrmittent ground or the trigger signal from the coil. As long as the engine runs smooth and strong, it isn't anything in the ignition system. If you re-establish the continuity of all the tach connections and you still have the problem, the tach is broken. Verne 
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#5
06-01-2008, 08:12 PM
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Re: Bouncing tach needle
Thanks... will try it.
__________________
~JAG~ NCRS#65120 68 GTO HO 4 spd Alpine Blue /Parchment 2 owner car #21783 71 Corvette LT1 45k miles Orig paint - Brandshatch Green - National Top Flight - last known 71 LT1 built. 71 Corvette LT1 42k miles Original paint - Black - black leather - only black LT1 known to exist. NUMEROUS Lemans blue Camaros, Monza Red and Daytona Yellow Corvettes & a Chevelle or two... Survivors, restored cars, & other photos https://picasaweb.google.com/lh/myphotos
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