View Single Post
island911 island911 is offline
Information Junky
 
island911's Avatar
 
Join Date: Mar 2001
Location: an island, upper left coast, USA
Posts: 73,189
Quote:
Originally Posted by Pazuzu View Post
Although, you said things don't change when the black wire is removed...
possible that you got a voltage spike somehow and you have an actual blown out tach? Internal damage?
Could be. I can, however get the tach needle to bounce up, by tapping the TD terminal to ground.

Quote:
Originally Posted by Jonny H View Post
Island,

Measure the voltage on the TD wire with ignition on, engine not running. Should be around 6.8 volts.

Now, measure the TD pin on the back of the tacho with the TD wire disconnected. Should be a little below battery voltage ~12v.

So if the wire is reconnected and you get ~12v it points to a broken TD wire. It you get 0v, probably means the CDI TD output is toast.

Cheers

Jonny
Another really great post. --I read your description of how the tach ground-pulses thru the CDI, on another thread. (very useful)

I'm going off memory, from a few days ago, and remember ~6V off of the TD terminal (when bare). I'll check these again.
__________________
Everyone you meet knows something you don't. - - - and a whole bunch of crap that is wrong.
Disclaimer: the above was 2¢ worth.
More information is available as my professional opinion, which is provided for an exorbitant fee.
Old 08-11-2014, 02:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)