VW Rev Counter Retrofit

[garry247]

I have taken alternator apart and added the cable so I can make the tachometer work. I have tested it and it’s sending a variable current with acceleration.

I tested the rev counter using the method above but connected it to a 12v battery and the alternator cable.

Pin 1 12v battery minus
Pin 2 TCA for 10v connected to 12v battery plus
Pin 3 cable from alternator

I get no movement. Any thoughts?

Am I testing it wrong?
Could I have the wrong wires set up and if so could this brake the tachometer?

[garry247]

You can see no w wire


Here you can see I soldered a wire in for the w feed


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[keynsham1]

I just added a pod with a rev counter and a volt meter in where the ashtray was. Very simple!!

[garry247]

Thx, if I can’t get this working I’ll resort to something similar

[garry247]

Tried testing with a battery charger on the coil. No difference but I did kill the coil

FYI I think I have a diesel tachometer on a dg1.9 petrol.

Has anyone successfully used a diesel tacho in a petrol. If so am I on the right track? W wire , 10v

Or have I missed something. I have just checked the tacho mechanism with the buzz setting on my multimeter and it moves the needle so either I’m doing something wrong or I have an issue on the board, however the board looks ok.

[garry247]

Any insight will be greatly received 

[R0B]

Worth a read  (13) Will a petrol rev counter work with a diesel engine - Club 80-90 Forums (club8090.co.uk)
(13) Tacho options for a petrol dash? - Club 80-90 Forums (club8090.co.uk)

[garry247]

Thx.

Where I am at present is

It looks like the diesel tacho will need a converter to work on a petrol even after adding the w wire (there seems to be conflicting info about this)

I could get a converter or get a Chinese taco and take out the circuit board.

I would buy the converter but I can’t find one that uses the w wire so I’m going to buy a Chinese tachometer and report back.

Unless anyone knows where I can get a petrol circuit board.

Thanks for all your help. This forum is fantastic.

[garry247]

Got it in and working by turning the little frequency dial on the back even without the 10v regulator.

However when I start her up again I need to wiggle the screw dial on the back to get it working. I’m going to try with the 10v regulator and report back.

G.