quad gauge rallye dash, no readings.

[JS29]

Ground the wire that plugs into the sending unit at the tank, it should peg out at full. that will test the gauge and wiring. Good luck!!! Mark.

[chargerdon]

Put in more gas !!!    So simple to do !!   On my 74 Challenger i have a new tank and new sending unit.   When full the standard gas gauge needle (not ralle) swings past the full mark...   If i drive it till it shows empty, then fill it, the most i have put in is about 12.5 gallons...   Now since it is a 19 gal tank, that means there is still at least 5-7 gallons in it when it shows empty.   So, add another 5 galls into your tank and see if the gauge doesn't start to work...   

To test the Gauge itself, take a good ground and apply to the sending unit post on the gas gauge, and turn on ignition...Needle should swing past F in just a couple of seconds.   

To test the sending unit, itself, use an OHM meter (multimeter set on resistance),  take the sending unit wire off gauge and use test ohms between it and good ground.   It should read:
at Empty 73 ohms, 22.8 ohms for 1/2 full, and 9.6 ohms with full tank.   (these numbers came from www.Chargersourguide.com gauges, fuel gauge.    I would think they would still be approximately accurate for our 70-74 E Bodies as well.   I have also read 80 ohms at empty, and 30 ohms at full...   

If sending unit isn't putting out the correct resistance, (with enough gas in the tank), then make sure at the tank there is good ground, and test the ohms right at the output spade of the sending unit!!   If nothing then test that the tank is grounded, by again using ohm meter between tank and good ground...and right on the sending unit to good ground.    I have seen where the sending unit isnt getting ground...   On my 74 there is a clip that goes from the ground source to the sending unit...   it could have become corroded.   If still nothing then probably a bad sending unit.   

Hope this helps. 



   

[chargerdon]

Oh here is the clip i was talking about:

https://www.ebay.com/itm/NOS-MOPAR-1963-74-FUEL-TANK-GROUND-CLIP-ALL-MODELS/232804036014?hash=item363433adae:g:ILsAAOxyuR5TYpQI

[culp71]

got them all to work!!
and a side thanks to Dave from Roseville as my complete dash is going back together for the last time! thanks to his restored dash dimmer switch!

she is 99.9 percent ready for that maiden voyage!

turns out the 5 gallons of fuel that I started with after running my cam break in was simply not enough fuel to register, so I added another 5 and gauge came up off bottom to the E mark, temp and oil pressure work too. found a original borg-warner stock headlight switch replacement unused still new in the vintage 70's box, and a nicely restored dimmer switch from Dave, its all going back together tonight!

[JS29]

  Electrical problems can get  But you stayed with it, and Concorde it!