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Model Specific Questions and Info => MK3 Golf/Jetta and B3/B4 Passat => Topic started by: Pawy on September 02, 2016, 02:29:38 pm

Title: Passat B3 tach problem
Post by: Pawy on September 02, 2016, 02:29:38 pm

Hello!

First of all here is a video of the problem:

http://youtube.com/watch?v=G2I3U_vulKc




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.

Title: Re: Passat B3 tach problem
Post by: vanbcguy 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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