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Author Topic: Passat B3 tach problem  (Read 1056 times)

September 02, 2016, 02:29:38 pm


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Passat B3 tach problem
« on: September 02, 2016, 02:29:38 pm »

First of all here is a video of the problem:

And a little back story, now week ago I bought a 1993 Passat B3 1.9TD (AAZ), it didn't had a tach, so I found one with tach, but only thing is that it's from B4 US or UK model. Basiclly it's jumping all over the place. At current time I have checked my wires by the alternator and they looked good, so I'm thinking is there a problem in car or it's cluster.

Any ideas or advice in this situation would be much appreciated.
« Last Edit: September 02, 2016, 06:44:07 pm by vanbcguy »

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Reply #1September 02, 2016, 06:47:30 pm


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Re: Passat B3 tach problem
« Reply #1 on: September 02, 2016, 06:47:30 pm »
Is the cluster for an AAZ or a TDI? The tach signal from the alternator is a much higher frequency than most tachometers expect. If it's a TDI tach rather than an AAZ tach it's probably expecting a signal from the crank speed sensor which sends 4 pulses per revolution. The alternator sends out probably 10 times that, which would lead to exactly the behaviour  you are seeing.

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Reply #2December 21, 2018, 02:00:03 pm


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Passat B3 tach problem
« Reply #2 on: December 21, 2018, 02:00:03 pm »
I looked at several KUS tachometers listed on eBay.  Your adaptation is innovative.
I assume that you purchased the model for a gasoline engine, rather than those for a boat or a diesel engine. 
Can the number of cylinders be changed with a switch or a wire connection on the tach ?

Charlie T.


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