[bwarrick]

I recently purchased a 1977 F-150. I bought a new Sunpro tachometer at Autozone last week and tried to hook it up. I can get the power and ground to work, because the needle immediately goes to zero. But when I hook up the trigger wire to the coil, nothing happens. Do I have a bad tach? I hooked it up to the coil exactly like the Autometer in my 68, and that one works fine. Is there a reason the duraspark won't allow the tach to work? Is there a different wire I should be hooking it up to? My thinking right now is that the tach is bad. I will hook it up to my 68 tonight and if it doesn't work take it back. Thanks for any ideas and help.

Brian

 

[gfmccann]

I have a duraspark in my Mustang. Although I don't have a tach in my car, when I hook up my meter for tuning I simply click on at the negative side of the coil and the tach in it works properly. Sounds like you may have a faulty unit.

- Gord

 

[66HertzClone]

I thought that this system had a terminal designated TACH. I seem to remember seeing that on the original installation. A wiring diagram may clarify this for you.

 

[68vroommm]

http://users3.ev1.net/~bmarr/57bcfe50.png

Here is what I did. The ground side of the coil can be connected to the tach as well. Every time the coil grounds (completes the circuit) the tach get the same signal. The tach needs to be set for a 8 cylinder. Should be some dip switches on the back.

....Re-reading your post. Seems like you are doing the correct wiring. I bet you have a bad tach.

Good luck.

 

[SAC69]

I have a duraspark and my VDO tack is hooked up to the neg side of the coil and works fine.