2 replies to this topic

[Mr W]

I have wired my tacho to either side of my coil, for power and sensing.

Its not going to set on fire or drain my battery is it?

Any help great fully appreciated

[dklawson]

No, the tach will be fine given that the coil it not powered when you turn the ignition key off. However, you need to make sure of one thing.

Some cars have ballast ignition systems. That means the coil operates at lower voltage during driving. Your tach will want a full 12V. A quick method to tell which type of ignition you have is to connect a temporary jumper wire between coil (-) and chassis ground. Then connect your volt meter between coil (+) and chassis ground. Set the meter to measure volts and switch on the ignition. If you see 12-13V, your tach will get the right voltage. If your meter displays 6-9V, you need to find another place to supply voltage from as your ignition system is the ballast type. The jumper wire must be installed for this method to work. The jumper wire has to be REMOVED to get your car to run again. The jumper simulates the points being closed (or electronic ignition module conducting). Left in place... the jumper wire is a kill switch.

[Mr W]

Its non ballast, thanks for the info