Started by RockwoodMike, July 29, 2023, 12:06 AM
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Quote from: Eyez Open on July 29, 2023, 11:32 AMyet to find a tank sending unit that is calibrated to the tank and gauges.
Quote from: DaveVA78Chieftain on July 29, 2023, 02:54 PM73-Ohm = Empty Reading. 10-Ohm = Full Reading
Quote from: DaveVA78Chieftain on July 29, 2023, 07:12 PMWill pipe in a bit of info:First, while not fuel gauge related, the Ammeter setup in that year model was a bad design. The Alternator output is applied directly to the Ammeter which has a bad habit of burning out over time and leaving you stranded (MAD Ammeter Bypass). The original Ammeter had the "shunt" inside the Ammeter which is what burns out. New style dash, RM and later series chassis with 3 round gauge clusters, changed the design such that a section of the alternator wire from alternator to starter relay actually functions as the shunt for the new style ammeter it reads as voltage drop (milliamps of current draw). The MAD article eliminates the ammeter from the circuit and recommends adding voltmeter to monitor alternator output. Note: Ammeters are actually voltmeters that are scaled to show amperage as a function of a voltage drop across a shunt.As far as the instrument cluster voltage regulator. The regulator itself is embedded inside the Fuel gauge and supplies reference voltage to both the Fuel gauge and Water Temp gauge. On RM and later series chassis' the regulator is separate and mounted to the rear of the instrument panel. While 12VDC is applied to the fuel gauge (jumper strap from ammeter), the regulator reduces the voltage to around 7 volts. So, if the dark blue wire between the fuel gauge and Water temp gauge is 12vdc rather than approximately 7vdc then the the regulator is shorted out making both gauges work incorrectly.
Quote from: Eyez Open on July 29, 2023, 11:32 AMI will be watching this one, I've a 80 gallon tank and yet to find a tank sending unit that is calibrated to the tank and gauges.
Quote from: BigAlsVehicleEmporium on July 30, 2023, 07:03 AMThe ohms range on this Dorman unit is 240 ohms empty and 33 ohms full. That range is used mostly for after market gauge
Quote from: BigAlsVehicleEmporium on July 30, 2023, 07:03 AMQuote from: Eyez Open on July 29, 2023, 11:32 AMI will be watching this one, I've a 80 gallon tank and yet to find a tank sending unit that is calibrated to the tank and gauges.Eyez Open,The ohms range on this Dorman unit is 240 ohms empty and 33 ohms full. That range is used mostly for after market gauge. If this is for your auxiliary tank and you have a separate gauge for it that isn't a Chevy gauge, it's definitely possible that this is the one you would need. If both tanks display on the same gauge and that gauge shows the level of whichever tank you are switched to, then you might need a 0 ohms empty, 90 ohms full sender like was used on most 1965 and up Chevys.I like the universal units that Tanks Inc sells and you can buy them in any of the common ohms ranges. Their TAN-GML model might be the one you need. If you're not sure, you could buy a few resistors to check if your gauge uses the range you think before buying a sender. If you've got any questions about trying that out let me know! I used there TAN-ORG model for my Dodge gauges and it worked out great!