Need Help with Tach signal.

[tvacc]

Hi all.

Have a 1966 Elan here. Positive ground. Just had the Tach rebuilt at Nisonger.

Put it back in car and it is still not working. I am missing something. It is wired properly as far as voltage. 12 volts positive to ground and 12 volts negative to power.

I must have the sensor wrong. White wire comes from the coil. From the negative post. Then goes to the ignition switch just like it is supposed to. Here are some pictures. I need help on this. Open to ideas on what I have done wrong or what I am missing.

[lotusfan]

Tony

It looks to me like you have assembled it wrongly. The 'U' shaped metal clip forms part of a transformer core and the coil of wire should go through it. What you need to do is to index you plastic block with the white wire through 90 degrees so that the coil of wire is inside the metal clip.

Clear??

[Craven]

Hi
Yes the metal bridge should fit in the groove on the block, you have it presently at 90 deg to where it fits.
Ron.

[billwill]

Tony

It looks to me like you have assembled it wrongly. The 'U' shaped metal clip forms part of a transformer core and the coil of wire should go through it. What you need to do is to index you plastic block with the white wire through 90 degrees so that the coil of wire is inside the metal clip.

Clear??

I'm not sure it is a transformer as such. But it is indeed at 90 degrees to its correct position.

It forms a conducting LOOP of metal, which in turn passes through the transformer which is inside the case. AS such there must be good cantact between the bridge piece (that the white wire is wound around) and the two fingers of metal which you can just see in the picture. If necessary clean the contacting sufaces.

On second thoughts, ignore the tiny text above.

It is indeed a transformer, the bridging metal piece and the two tongues sticking out of the back of the tachometer are of magnetic material and form a magnetic loop. The white wire (en-route to the ignition coil) wound around the bridge piece forms the primary of the transformer and the secondary can be seen in the following photo as a coil of fine wire covered by a yellow plastic sleeve.

Smiths Tachometer Signal input (RVI type)

[tvacc]

When I bought the car, the previous owner had it this way and the tach was not working. So I sent it out. Probably was ok. Can someone take a picture of how it is supposed to look like? A picture is worth it all on this case. I have not seem one of these set up right since my last S2 which is. almost 50 years ago.

[tvacc]

OR if someone can point me to an illustration in some book. I probably have all the books.

[billwill]

This image from the photo library shows how it should be:



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lotus-electrical-f38/tachometer-reading-too-high-europa-t21763.html