Thank you for the help on the fuel gauge post. I have bought a new CVR for the gauges as the fuel gauge is now wired correctly, but dead unless I hot wire it with 12v as the CVR is putting out between 2v and 0 ( digital meter jumping around?). My question is what should the new one be putting out? I grounded the housing and put 12v to the ign side and am getting a dancing reading on the digital meter between zero and thinking about it. Do these not work unless under load or do I need a analogue meter to test? Thanks.

 

The CVR does "pulse" an output to the guage. You will read pulses, not steady voltage. An Analog meter will read pulses also. The purpose of the CVR is to keep the guage needle from bouncing all over the place, if it is not used. A fuel guage would be useless because of all the "bouncing" without the CVR.

In essence it creates an RMS value (average voltage) that is less than the system voltage that the guage actually reacts to, depending upon the frequency of the pulses. All that is factory designed, we just get to buy the correct CVR and guages.

Make sure the guage is of the correct value and does work with a CVR (you may already have).

You can get a variable ohm pot (AKA potentiometer) that has a range the same as the tank sending unit and by using it (disconnect leeds between guage and tank sender) and a multimeter, you can verify guage, and sending unit operation. A shop manual should give the range, in ohms, from "F" to "E" of the tank sender. I wouldnt be supprised if almost all ford units use the same values.

Hooking system voltage to the guage will "slam" the needle to the stop and may damage it. The "ground" (RTN) side of the guage wires to ground thru the windings on the tank sender. The "hot" (Batt) side of the guage should feed thru the CVR.

LOL

 

Thank you very much!