Autometer diesel tach

Discussion in '6.9L IH & 7.3L IDI Diesels' started by austin92, Dec 8, 2018.

  1. austin92

    austin92 Full Access Member

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    Has anyone used the autometer tach that uses the alternator as its pick up? My 83 doesn’t have a factory tach and I have a gauge fetish or something lol.

    Here’s a link https://www.autometer.com/2-5-8-tach-5-000-rpm-diesel-4437.html

    If enough people are interested and no one has experience with them I might try one out just to be the guinea pig.



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  2. 79jasper

    79jasper Chickenhawk

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    Cant say that I've seen anyone run one here. But they are popular in the gm 6.2/6.5 world.

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  3. jayro88

    jayro88 Full Access Member

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    I believe Genscripter is running an alternator pickup tach on his e250, but I don’t know which specific one. I was looking at adding one for my e250 eventually.


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  4. austin92

    austin92 Full Access Member

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    I’m just worried about accuracy with the alternator pulley being smaller than the crank.


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  5. jayro88

    jayro88 Full Access Member

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    I know you usually have to do some kind of calibration with it. I haven’t looked into them very much since adding one is fairly far down on my list of things to do to my van.


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  6. austin92

    austin92 Full Access Member

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    Their video shows you matching up the tach with engine speed at idle. Would it still be accurate at 3500?


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  7. Booyah45828

    Booyah45828 Registered User

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    Should be close. They count the field pulses at idle from the alternator. With that data point they can extrapolate out the rest of the rpm range. It's accurate as long as the alternator is working and the belt isn't slipping. This kind of alternator tach has been used for a while. Old ones used a stator tap on the alternator but this design includes it's own sensor.
     
  8. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Its pretty accurate, cat uses this kind of tach on the old 3116s. If you have a timing meter you can use that to calibrate the idle rpm and make sure its accurate throughout the rpm range.
     
  9. gfemling

    gfemling Registered User

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    I got fed up w the factory tac in my 87 and several years ago installed one of the Autometer that uses sensor clamped to the alternator case and has been accurate- as far as I can perceive- and reliable. Do recall that needed to adjust/calibrate on installation. Over all I am happy with it.
     
  10. austin92

    austin92 Full Access Member

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    That’s what I planned on doing, just didn’t want to waste my time if a few people had bad luck with them

    This is what I wanted to hear, thank you



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