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Tach way off

Started by mjb765, April 30, 2017, 04:30:41 PM

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mjb765

I have been e-mailing Instrument specialties and he said that maybe the tach needs to be updated to modern electronics since it may not work properly with modern ignition. Since they calibrated it already and charged me, it would ONLY be $200 to upgrade the tach completely.

JS29

 Since they calibrated it already and charged me, it would ONLY be $200 to upgrade the tach completely.
[/quote]      :headbang: :pullinghair: :verymad:

blown motor

Quote from: 61K T/A on May 01, 2017, 02:02:05 PM
Here's a shot in the dark. MSD makes a tach adaptor. Basically it's a signal amplifier. Maybe Pertronix makes one too.  Maybe there is a signal issue here rather that a calibration issue. You might be battling a weak or floating input signal. Other than using an oscilloscope to check amplitudes I dont know any other way to accuratly check the input signal to the tach. Also you can see if it's a clean signal or not ie. amplitude  differentiating or attenuating signal patterns. If the signal is dirty you can back track it with in the circuit to the source. This was one of our trouble shooting techiques we  did in my main frame gate chasing days.

I have an Autogage tach on the column and we powered it by splicing into the wire going to the dash tach. I believe it to be accurate so it would seem that the signal is good. Not?
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mjb765

Quote from: blown motor on May 01, 2017, 02:52:35 PM
Quote from: 61K T/A on May 01, 2017, 02:02:05 PM
Here's a shot in the dark. MSD makes a tach adaptor. Basically it's a signal amplifier. Maybe Pertronix makes one too.  Maybe there is a signal issue here rather that a calibration issue. You might be battling a weak or floating input signal. Other than using an oscilloscope to check amplitudes I dont know any other way to accuratly check the input signal to the tach. Also you can see if it's a clean signal or not ie. amplitude  differentiating or attenuating signal patterns. If the signal is dirty you can back track it with in the circuit to the source. This was one of our trouble shooting techiques we  did in my main frame gate chasing days.

I have an Autogage tach on the column and we powered it by splicing into the wire going to the dash tach. I believe it to be accurate so it would seem that the signal is good. Not?

makes sense to me....

Chryco Psycho

you usd to be able to just buy the kit for $70 or so & do it yourself from RTE

Wedg2Go

Quote from: Chryco Psycho on May 01, 2017, 04:02:45 PM
you usd to be able to just buy the kit for $70 or so & do it yourself from RTE

I know this is an "Old Post", but thank you Chryco Psycho for that bit of info. Much appreciated!

Chryco Psycho

Glad to help , I have upgraded a number of tachs using the RTE kit