Mick,
Please do not mess with the guy....
The "TANK" does
not to be grounded, The GAUGE DOES!
The wire he addresses is labeled 190 and IS for the sending unit-NOT the tank. The extra ground I am referring too is a redundant and
dedicated Ground for the Sending unit, not the tank.
CR's has supplied the Ground in their Wiring Harness, tied into multiple grounds in their system.
Yup the sending unit you are talking about has a "Bakelite" material insulating the entire gauge - electronics, as all sending units are insulated from the tank. However the Gauge/sending unit Does need to be individually grounded.
The point I made regarding the OHMS are NOT the type of unit or OHMS to use but to make sure the sending unit-gauge head will / do Match!
The common OHM units you mention are GM-
0/90, the
33-240 are usually used in Ford and/or Chrysler.
The problem usually comes about when the sending unit does not match the gauge or (receiving unit) as mentioned.
I.E.; A friend, George, who owns the '40 Willy's I am building had a similar problem that Andy mentions. He has "Autometer" gauges including his Gas Gauge. For ease and accuracy he ordered the exact sending unit that you have described. The Gauge ultimately went whacko! Come to find out George lost his working brain cell and ordered a FORD sending unit knowing full well his Autometer as based on the GM designed OHMS.
Even though George had cut/adjusted the new style sending unit to fit his fuel cell, Pegasus sent him a brand new -OHM's Matching- unit at no charge! Pretty cool.
Oh Well-the sending unit supplied with the CR's gas tank is just fine. The optional sending unit you describe is good- very good, but absolutely NOT needed. to fix Andy's problem.
DV