Pontiac GTO Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
put in a tach were the clock was. hooked the 12 volt then one to the coil with fuse the tack goes up when you first start it and that's it do you think it's because pertronix . I was told it would work
 

·
Registered
Joined
·
3,759 Posts
put in a tach were the clock was. hooked the 12 volt then one to the coil with fuse the tack goes up when you first start it and that's it do you think it's because pertronix . I was told it would work
Assume this is not a factory style aftermarket tach, but an add-on type.

You should have more than 2 wires. You should have a red 12V power wire. Black ground wire, White 12V wire for tach light, and Green wire to (-)Negative side of the coil.

No, Pertronix install should not create a problem, but there have been some tachs that may be affected by the conversion. I had Pertronix with a standard add-on type tach and had no issues.
 

·
Registered
Joined
·
3,759 Posts
This is a factory replacement tach two bulbs 12 volt wire and one to the coil
OK. My next thought would be, how is it grounded? It may be a ground issue. It may be grounded through the circuit board or it may use a separate grounding strap/wire.

It could also be defective, but I would check all avenues first before looking for a refund or replacement.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
the circuit board has a ground and I tried a extra one it Must be bad . thanks for your advise jim
 

·
Registered
Joined
·
13 Posts
I also have a 68 GTO with Pertronix and did the exact same thing. I had a NOS tach never used still in the GM packaging. I also installed it where the clock was. When I run the car the needle moves up ever so slightly. Maybe 500 rpm or so and then it goes down. There’s supposed to be an adjustment hole in the back of the tach for a very small screw driver to adjust it. I never tried it cause it was so difficult for me just to install it. I put it on the list to have someone other than me with my sausage fingers look at. That was 3 years ago.
 
1 - 6 of 6 Posts
Top