Installed sending units in aluminum manifold. Do I need to run additional ground to sending unit. Sending unit is not registering.

Thanks
Sheikman

Not registering at gauge?
Some sending units are not compatible with certain gauges. It's possible the replacement isn't. What gauges do you have ?

VDO Gauges...
Formula 242 stock set up.
Took sending units off 454/365 mag motor.

Did you use teflon tape on the
sender threads ?
If so, you may have lost continuity
to the intake/ ground.

jt.

Take a wire with two alligator's clips on it. Now test it by grounding one side to the shell of the case and then to the negative on the battery.
This should tell you if you need it or not.
Good luck.
Brian