BJ8 tach

[Marvin Gruber]

Sorting out a couple of electrical gremlins. The tach is not working, checked for voltage, its there. Have the loop in the white wire. Needle will flicker when I remove grd wire but nothing while its running. Any thing else to check. If I need to send off for repair, who do you recommend?
thx,
Marv

 

[Healey Nut]

Reverse the direction of the loop ... did you change the car from + to - ground ?
Nisonger instruments .

 

[Keoke]

Reverse the direction of the loop ... did you change the car from + to - ground ?
Nisonger instruments .

Yep I will second those suggestions.

 

[Marvin Gruber]

Still pos grd, changed loop directions so guess I wil be sending it off.
Thx,
Marv

 

[Patrick67BJ8]

Still pos grd, changed loop directions so guess I wil be sending it off.
Thx,
Marv

Mine wasn't working until the temp got up by driving it and then reading was low. I converted to Neg ground and run Pertronix. Sent Tach to Nisonger and they installed new inards that will also work better with Pertronix and other hi-performance Ignition systems. About $300 and no more "loop" to contend with!

 

[Marvin Gruber]

Boxed up and ready to ship in the morning to Nisonger.
thx,

Marv

 

[RAC68]

Hi Marv,

Prior to totally failing, did your tachometer read high? There is a known problem with our electronic tachometer where a 2uf capacitor deteriorates and eventually fails to a shorted or open circuit. It is reasonably easy to replace the part and recalibrate the tachometer.

Attached is a document written by Frank Filangeri that addresses this condition that could be the cause of your problem. One last point, Frank describes this capacitor as tubular in structure. However, I found my capacitor to be more disk like. so either could be presented.

Hope this helps,
Ray(64BJ8P1)

 

[Bob_Spidell]

I can attest that the calibration procedure works.

 

[cpbol]

Is the 2uf capacitor you are referring to the round disk-shaped component in the center of the image that has the paint burned off?

 

[Marvin Gruber]

My tach didn't work at all. I sent it off to Nisonger and had it converted so no white wire loop. I got it back and it read 2x what is should read so I sent it back. I have it back now but have not installed yet.

Marv