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Author Topic: Factory Tach question  (Read 14751 times)

Offline hatzie

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Re: Factory Tach question
« Reply #15 on: March 07, 2015, 10:28:51 am »
The tachometer signal is a variable  frequency and amplitude pulse.  I looked at the signal on my oscilloscope and it rings in decreasing amplitude waves after the initial pulse.  The frequency of the largest pulse is what the tach uses to determine the RPMs. You will not measure any meaningful output on the tach lead with a basic multimeter.
Fluke 115 and Klein MM200 multimeters measure frequency in hz but the ringing will cause some variability.
An " Automotive" multimeter will be a better test tool.  An automotive multimeter will have tach and dwell functions as well as ohms & volts-DC and maybe diode test and or continuity buzzer.
http://www.google.com/search?q=tach+dwell+digital+multimeter


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« Last Edit: March 07, 2015, 10:39:12 am by hatzie »
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Offline 76K20

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Re: Factory Tach question
« Reply #16 on: March 07, 2015, 08:16:44 pm »
Well got her fixed today.  The problem was the wire from the distributor to the tach, ran a new wire and now she works like new.  Thanks for all the help guys.  Alan
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Offline LTZ C20

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Re: Factory Tach question
« Reply #17 on: March 08, 2015, 01:33:42 am »
Good to hear.
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Offline hatzie

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Re: Factory Tach question
« Reply #18 on: March 10, 2015, 07:59:18 pm »
Good stuff. 

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SVC & wiring mans --> Here http://tinyurl.com/7387BRD-SVCMAN or My Bucket @ http://tinyurl.com/SQ-SVCMAN
Parts & Illustr Books -->http://tinyurl.com/SqParts
GMSTG Textbooks-->http://tinyurl.com/STG-TEXTBK
Radio Manuals-->http://tinyurl.com/DELCORADSVC

Offline Dan75k20

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Re: Factory Tach question
« Reply #19 on: June 08, 2015, 01:21:26 pm »
WhT did you do about the resistor?
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Offline 76K20

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Re: Factory Tach question
« Reply #20 on: June 15, 2015, 07:29:49 pm »
nothing just ran a new wire.
Quote from: Dan75k20 on June 08, 2015, 01:21:26 pm
WhT did you do about the resistor?
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Offline Dan75k20

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Re: Factory Tach question
« Reply #21 on: June 15, 2015, 07:31:33 pm »
Cool thanks!
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