New fuel send unit and tank - no more level reading

[NorthGaAire]

So I just installed a new MTS tank on the 78cherk. I also installed a new level sending unit and fuel pick up.

I replaced the old MTS tank with a new one - hopefully one that will not leak from the sending unit ring.
The newer MTS has the 8 clamping screws on both the sending unit and pickup rings....

With it back together ==> no level reading on the gauge. It is holding on E.

The sending unit has the one wire plus ground from the clamping screw to the frame.

Old sender and gauge worked before the tank/sender install.

Any thoughts on a starting place?

If the ground is good on the sending unit - will it peg to F or E?
or if the ground is missing will it peg the gauge?

Thanks.

[tgreese]

You should read the TSM about this. There is a section specifically about the instruments and testing with instructions for diagnosis. https://oljeep.com/edge_parts_man.html Free to read and download.

That said, you test the gauge and sender separately. Jeep specifies a special tester, which supplies a fixed resistance. You can easily substitute fixed resistors and some clip leads for the tool. You test the sender with a multimeter.

Kind of late now, but always test a replacement sender with your multimeter before you install it. It is a variable resistor, and the resistances for E-1/2-F are given in the TSM. You can momentarily ground the sender wire to test the gauge - it should move - but don't hold the sender wire to ground for a long time.

[NorthGaAire]

Update -
The sending unit housing was not grounded to the frame.

The new MTS tank comes with a round O-ring gasket and clamping ring.
The tank also has 8 screws with clamping plates around each opening - pick up and sending unit.

The new sending unit comes with another flat profile gasket. There should only be one gasket used - the round one that sits under the
sending unit flange in the groove on the tank.

The clamping plates clamp down the clamping ring on top of the sending unit flange.
Seems to work fine now. (Well as fine as can be expected.)

Thanks