Tach problems

[commplexone]

I just purchased a 72 240z project car that runs well. The only real problem with the interior for me is that the tach doesnt work. It wont work unless you hold the ignition key about 1/8th of an inch to the right, then all of a sudden it pops on. Does anybody have any advice on how to fix this problem? Its so weird, i can be cruising down the street and want to know what i am taching so i just turn the key to the right a bit and boom it comes on.

[sblake01]

Sounds like the electrical part that attaches to the back of the ignition housing either need to be cleaned (I've never done that) or replaced.

[EScanlon]

Check for the following wiring at the coil or connected to the resistor right below:

Two Black/White wires

One Green/White wire.

The Green/W wire is not connected properly as well as one of the B/W ones.

Once you've found all three wires, I'm betting that both B/W wires are connected to the same terminal on the coil (and for FYI, it should be the positive terminal).

If that is the case, start the car, and disconnect one of the B/W wires. The car should stop, if not re-connect and disconnect the other. The B/W wire that causes the car to shut down should be connected to either the G/W wire or to the resistor located by the coil (if you have points). If you don't have points and are using the electronic dizzy upgrade, then just connect to the G/W.

This should correct that wiring and get the tach working...as long as the tach isn't faulty also.

Enrique