I had two electrical oil gauges working reading/fine but the setup using two sending units started leaking badly and I couldn't get it to stop so I went back to one sending unit & gauge, disconnecting the factory gauge. I then restarted her and the gauge stopped working(Auto Meter Pro Comp Ultra Lite). Also the Auto Meter temp gauge stopped working but the voltmeter is still working fine. Like I said earlier all gauges were reading and working fine until I went back to one oil gauge. (I used pipe thread as instructed on the directions.) But I did not touch the water temp. gauge. I did have to disconnect the coil & wires hooked to it in order to get me "meatloaf hands" in there and reconnected everything back as it was previously. Also the gauges back lighting is illuminating, but gauge is dead. Gauges are less than 6 months old and were working fine a week ago.
Lil' help fellas???

Engine 273 Commando - '66 Barracuda F/S

The threads on the sender have to be grounded to the block to complete the circuit. Your sealer tape is insulating the ground.

That's what I thought but why do the directions say to use pipe thread? And why is it affecting my temp. gauge but not the voltmeter? Is it because they are tied into the same circuit some how?

Thx, for the quick reply, I am waiting for the motor to cool in order to remove the pipe thread and reinstall.

Voltmeter isn't grounded through a sender. The senders must be grounded because they work on resistance.

I don't think the ground at the sender is your issue. You said your temp gauge quit also? Are these gauges all aftermarket? Some gauges MUST HAVE the "shell" of the guages grounded to work properly. These are known as a "bridge circuit" or a "wheatstone bridge"

Yes, all 3 are aftermarket Auto Meters in a gauge pod sold by Auto Meter and each one was working fine last week when I was out cruising last week. I noticed that the leak I thought I corrected for the "tenth time", had started again. Today was my first chance to work on her. I hooked up the factory gauge & sending unit (using pipe thread) and it works fine.