67 twin turbo dart

The ground wire is brand new only added it a little bit ago and connects to the negative post I have on the firewall. Well according to speedhut when you ground the signal wire its suppose to sweep on through gauge since that's what it does is grounds out through the threads, well the other sensor did and I had a ground on the threads and on the remote oil filter mount. This new one had a ground wire in on the connector, still left the one on the filter mount. A double ground wouldn't cause any issues since they both go to batt ground, should it?
Is there 2 wires coming from the meter or 1