Tach on 1.6D???

[Tmarkle]

So I tried to wire in an Autometer tach to my VW, I bought a new alternator from NAPA (old one was bad) and it happened to have the W terminal, so I thought, sweet! I can wire in a tach! well I tried to wire it in and for whatever reason the tach goes from 0-4k rpms on startup and doesnt look like its moving properly... Ideas???

[burn_your_money]

Do you have a proper signal from the W terminal? I think you're looking for 8 VAC.

[Tmarkle]

Do you have a proper signal from the W terminal? I think you're looking for 8 VAC.

Honestly didn't check. I'll test it and see.

[libbydiesel]

Is the Autometer tach for a gas engine?  If so, it will not work with the W terminal. 

[vanbcguy]

Is the Autometer tach for a gas engine?  If so, it will not work with the W terminal.

...at least not without an adapter.

As you've noticed the alternator signal is much higher frequency than a gasser ignition signal which is what that tach is expecting.

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[Tmarkle]

Is the Autometer tach for a gas engine?  If so, it will not work with the W terminal.

...at least not without an adapter.

As you've noticed the alternator signal is much higher frequency than a gasser ignition signal which is what that tach is expecting.

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Where would I get such an adapter? Yes it's for a gasser, I bought it for another project and thought I would utilize it for this car.

[vanbcguy]

Dakota Digital make the only adapter I know of that's premade. I've never had to use one.

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[Tmarkle]

Dakota Digital make the only adapter I know of that's premade. I've never had to use one.

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Could one make their own adapter?

[vanbcguy]

There's a few examples around the forum where people have used a magnetic pickup and a magnet or two attached to the IP or cam pulley to trigger a gasser tach.

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[libbydiesel]

There are quite a few tach options available:

Get a stock diesel tach for your model and run it off the W terminal.
Get a stock gasser tach for your model and replace the necessary components to turn it into a diesel tach and run it off the W terminal.
Add an inductive probe and a couple lugs to drive a gasser tach off the crank.
Get a Tinytach and run it off a piezo pickup on an injection line.
Get an optical sensor kit from 4crawler and run a gasser tach off it.
Get the Dakota Digital signal conditioner and run a gasser tach off the W terminal.

I've personally done the first three options and they each can work fine.  I like the stock tach look so tend to go that direction.  There are probably other options that I'm forgetting.

[Tmarkle]

Ok thanks I'll see what I can figure out!