Rev.counter not working

rev.conter: it is not working. only shivering around bottom. what to do ?

Check the wiring?

Don’t know what our model is or how they developed but if it’s like my 62 an easy to get to fist item is to check your tach generator output on the back of your intake cam.

They are know to have a couple of problems. One of them is for the pin to shear inside the generator and not drive it properly. Very fixable.

OP lists a 1970. Is it this simple, or something more?

image

torrox,
What year is your E-Type and what engine does it have in it.

Paul

Your Series 2 will have the later tach - no generator on the exhaust camshaft. Pretty simple circuitry. There’s a loop in the ignition wire over a transformer that converts the flux from ignition pulses into voltage pulses that flow through the needle and cause it to deflect. The faster the engine turns the more rapid the voltage pulses and the greater the needle deflects. There are a couple of transistors in the circuit and three paper capacitors, all of which can become heat sensitive or simply fail. There is one cap in particular that goes flaky most often but I can’t recall which. In any event, electronic rebuild is the way to go. I sent mine off to Morris Mintz at West Valley Instrument Specialists and 3 weeks and $165 later (with shipping, but that was 10 years ago) I had it back. One extra wire to the coil and it works flawlessly, and dead accurate.

Perhaps play around some with the loop portion of the white wire on the back of the tach. My white wire melted several years ago when the ignition switch fried so I had to replace that whole section. At first the tach did not work but after I moved the loop around some it started working again and no more problems since. Just a thought.

David
68 E-type FHC

Assuming the wiring is OK, replace the electrolytic capacitor inside the tachometer and you’ll be back in business.