MSD Ignition and Distributor
Thread Starter
Racer
Joined: Nov 2008
Posts: 315
Likes: 46
From: Chicago Illinois
MSD Ignition and Distributor
I recently installed a MSD Ignition and distributor, my question is now my AMP gauge wont work I believe its connected through the coil/starter. Looking for help to get it to work.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
We would have no idea of what wiring changes you made during the MSD install. You probably 'cut' the ammeter out of the circuit during your work, but there is no way for us to know for sure. The ammeter gauge on a '70 C3 is connected across a length of wire built into the wiring harness. From the electical diagram is appears that there is a straight run of wire connected to both gauge terminals. In fact, that is exactly what it is. That length of wire acts as a very small resistor...or "shunt"...connected to a millivolt meter (what that gauge actually is) so that it wil display AMPS on the meter scale. The current [being used by the vehicle at the time] passes through that wire and creates a voltage drop that is read by the meter...which displays the amperage draw in the system. If you re-routed or disturbed any of the wires connected to the ammeter, that is probably why the meter no longer works. Other possibilities are that you loosened some connection in the system or that the meter failed during/from your work or just from "age". You would have to provide a drawing of what revisions you actually made [not what you think you made] for us to help you any further.
