Topic: 69 Mach 1 Tach Issue Help

[Bob Gaines]

Makes sense Bob   I appreciate the input. I was told to take the red wire for the Pertronix off the coil and put it directly to the battery power to see if the tach then would work when starting. The car would start but the tach still didn't work.   That's kind of the same thing here isn't it with putting in a wire to the ignition 12v to make it work?   It was just a test doing it that way but it didn't work so it again sounds like the tach itself?



Chad

Your test is sound and what is called "hot wiring" a car to bypass the key. I suspect that your tach is damaged as the reason it doesn't work given the test. I would not have it fixed and try it again unless you follow the direct wire to the Pertronix process.

[STAUBY38]

Ok   I will do that.    Is there a specific wire(color) in the ignition just outside of the ignition switch that should be used to tap into for this ?   I am wondering if having it converted to the 3 wire set up would eliminate this issue ??

[Bob Gaines]

Ok   I will do that.    Is there a specific wire(color) in the ignition just outside of the ignition switch that should be used to tap into for this ?   I am wondering if having it converted to the 3 wire set up would eliminate this issue ??

You want to tap in between the ignition switch and the connector of the wire that the tach plugs into .  The  other tach wire plugs into the wire that goes to the engine gauge feed harness in the engine compartment.You should not have difficulty identifying this wire as it is a short distance between the switch and the connector that the tach plugs into. I am not familiar with the 3 wire conversion your tach guy is talking about. It sounds like it might be a additional wire on top of all of the others seperate that runs out to the coil. I would want less wires not more but that is just me .If you don't have the assemblyline manuals you should get a set if working on the car yourself. At least get the electrical manual for future use. That electrical manual will have the wire schematic. A simple way to determine the correct wire is to find the wire with the connector end that the tach plugs into and trace it back. The wire to the ignition switch is short. 70 is hard to find if you don't have a wire color because it runs up in the column . 69 is easy peezy by comparison .  In the back of the switch mounted on the dash follow a wire that goes up to the tach. The wire should not be hard to find . It will be easiest to take the driver seat out . I typically don't but I am flexible. For me I would not think twice on what to do. If you are unsure of your abilities you have to decide what you think is best for you. Best of luck on what ever you decide.

[STAUBY38]

Appreciate your help !!