Isspro Tach Users, Intermittent Operation=Bad Sender?

[joed]

The previous owner installed an isspro tach on my 82 - it's a larger one, 0-5000 rpm, placed where the large fuel gauge would normally be. The sender is a magnetic one, glued to the harmonic balancer.

Lately, especially with the warmer weather, the tach will work fine for a while and then just drop to 0 and quit working. If the truck cools off for some time, especially overnight, it will work fine, so it seems to be more heat sensitive than a loose/broken wire. Before this started happening, the tach would occaisonally "freak out" and jump around sometimes, but always kept working.

For those that have isspro tachs, have you experienced this intermittent problem before? If so, is it likely the sender, gauge itself, or other wiring?

Thanks. Joe.

[john8662]

Have an isspro 2 1/16 size gauge that goes up to 4k it's operated by two rare earth magnets glued 180 degrees from one another onto the harmonic balancer. Where the previous owner managed to position the sender unit can be a mystery, but you know it's in the general vicinity of the haronic balancer.

As always, check the electrical connections to the sender. The sender could also be loose where it's mounted and driving actually makes it worse. I've got my sender positioned approx. 1/4" from the magnets themselves and haven't had any problems. If the sender and the magnets get too much distance, then perhaps this problem will occur.

J