tacho censor details

[aquapore]

I have a d2-55 engine with a dud tacho which is beyond repair.

Does anyone know the electrical character  of the tacho sensor.

Regards

Aquapore

[sy_Anniina]

First I would check the wiring and all the fuses on the wiring diagram.

How do I know? MD22 engine with dead tacho.. bought already a Henric alternator-connected-tacho, but found one loos connection and one tripped fuse.

BR,

Tommi
S/Y Anniina

[SYJetzt]

D2-55 Engine has a magnetic sensor on the flywheel, connected to the MDI, which converts the signal to serial and then to the tacho. See attached document.

[aquapore]

Thanks for your reply.
My engine is a D2-55 presumably "A" version 2002 build. I don't think it has an MDI.
I will look at the tacho input signal with a oscilloscope and try to find a replacement.
My original shows burn marks caused by water ingress.

Does any one have a circuit diagram of these units. I will try to repair it.

Regards

Aquapore.

[SYJetzt]

I think you're right about the missing MDI.
Maybe check this link https://www.manualslib.com/manual/1025286/Volvo-Penta-D2-55.html?page=94#manual
Seems it is a magnetic (hall?) sensor with direct connection to the instrument.