i am putting a cummins engine in to a ford and i don't want to spend alot of money to a"kit" to make my tach work and would rather fix it my self i have a hall sensor that has two hashes on the harmonic balancer on the cummins and a tach on the ford that needs 12 pulses from what i am told to get the tach to work properly on the ford which requires a mag pickup signal i was also told that i need a pulse multipler to get the signal where i need it HELP


thanks

 

Hi Choco. I remodeled a VDO tacho & used this circuit to drive the meter & it uses a Hall device found in many VCRs as a reel sensor. I made this setup to put on a Yanmar diesel in a boat & stuck a magnet on the crank pulley, its still working 8yrs later.

 

This is how i calibrate Hall driven tachos using 50Hz, this gives a reading of 3000Rpm when the Hall is held near the open end of a small solenoid (this to came out of an old VCR) This calibration is for one magnet on a pulley, if 2 magnets are used halve the RPM.