Bouncing tach - Pontiac GTO Forum
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post #1 of 5 (permalink) Old 11-10-2012, 04:28 PM Thread Starter
 
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Bouncing tach

Fired up my 71 lemans for the first time. Had to cut it short due to a bad coolant leak.
The issue is the tachometer isn't reading steady. It'll try and read correctly but bounces around and drops to zero for a bit.
I have the crane cams xr-I conversion installed without the ballast. I also don't have the tach's lighting wire hooked up.
Any one have ideas why it's doing this?
Good news is it fired up easy once it had gas.


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1971 LeMans 350ci 2Barrel Carb

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post #2 of 5 (permalink) Old 11-10-2012, 04:42 PM
 
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Are you using an original tach with an HEI distributor?

1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base
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post #3 of 5 (permalink) Old 11-10-2012, 05:28 PM Thread Starter
 
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It's a repro tach. Points distributor with the crane cam xr-i electronic conversion


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post #4 of 5 (permalink) Old 11-11-2012, 06:53 PM
 
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I know the original tachs won't work properly with the GM HEI distributors, but i can't help you woth your combination.

Any chance you can get answers from the company that supplied the tach? Sounds like it doesn't like the signal from the crane unit...

1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base
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post #5 of 5 (permalink) Old 11-11-2012, 10:45 PM Thread Starter
 
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I read something on needing to put resistors in the tach wire somehow.



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1971 LeMans 350ci 2Barrel Carb

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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring
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