Encoder Driven Tacho

[GoneDiving]

Does any one have instructions or a wiring diagram to install an old encoder/pulse generator driven tacho in a Mercedes OM355?

Thanks

PS. Yes I know it needs a clean. ?

 

[Choices]

How do you know it's an encoder input? You need the encoder ratio to use the correct one. It's a VDO car or truck tach. Post question on Mercedes restoration forum. Post answer here!

My guess is an enoder input would be similar to a spark plug wire, but at a fixed 6-12 voltage.

 

[Bmarler]

Depending on its age it could also be a voltage generator. X amount of volts per hundred rpm. Spin it up with a drill or something and put a meter on it and see it that might be the case. If so, it’s just the two output wires to the two input terminals.

 

[Nick F]

I have recently worked on my own (Stewart Warner) tach senders. This type probably works in a similar way. If so, you should hook it up as follows:

Sender:
Body is the negative connection
Brown wire is the battery (+12V) connection
Blue wire is the signal

Instrument:
Body (case) is the negative connection
Red wire is the battery (+12V) connection
Blue wire is the signal (and should be connected to the blue wire terminal on the sender)

Test it at home with a 9 volt battery to supply power to the sender and to the instrument. Spin the internal rotating part of the sender a bit (by hand? Battery drill?) and you should see the instrument show some reading.

Good luck!
Nick

 

[GoneDiving]

Thanks everyone

"Hi, it is an inductive ( makes its own ac power) generator sender. The two wires should go straight to the tachometer and the tacho should have its own earth and illumination wire. Doesn’t matter which way the wires go."

 

[Nick F]

I have recently worked on my own (Stewart Warner) tach senders. This type probably works in a similar way. If so, you should hook it up as follows:

Sender:
Body is the negative connection
Brown wire is the battery (+12V) connection
Blue wire is the signal

Instrument:
Body (case) is the negative connection
Red wire is the battery (+12V) connection
Blue wire is the signal (and should be connected to the blue wire terminal on the sender)

Test it at home with a 9 volt battery to supply power to the sender and to the instrument. Spin the internal rotating part of the sender a bit (by hand? Battery drill?) and you should see the instrument show some reading.

Good luck!
Nick

Please disregard my post!(repeated above)
Nick