I have a 70 300Hurst and the gas gauge is getting less accurate with passing months/years. It used to read a bit more than 3/4 when full, but now it barely makes it up to 1/2 when I fill up. I don't believe it's the voltage regulator for instruments as everything else on the car seems to function properly. What should resistance measurements be on the sending unit when full and when empty? My 70 shop manual doesn't list the values. I've heard lots of 'stories' about aftermarket replacement sending units not being correctly calibrated for our cars?
gas tank sending unit specifications
- Thread starter noah300g
- Start date
10 ohms full.
23 ohms mid range
74 ohms empty.
And something to consider is a Meter Match that compensates for sender inaccuracy. My adventures with senders and the Meter Match here: Gas Gauge Fix
And if you don't have a resistor decade box to check the gauge, there's this: Gauge Tester
23 ohms mid range
74 ohms empty.
And something to consider is a Meter Match that compensates for sender inaccuracy. My adventures with senders and the Meter Match here: Gas Gauge Fix
And if you don't have a resistor decade box to check the gauge, there's this: Gauge Tester
Thank you,
I have an almost full tank of gas in the vehicle right now, and I get a reading of about 50 ohms when I measure the sending unit with my multimeter. Guess I'll have to burn off some gas and then remove the unit and check the float and the windings on the rheostat. Good time to see how the filter/sock looks on the end of the pickup tube as well, since it's all original and never been opened up before.
Yea, that sounds like the sender is toast.
I've had good luck with a Spectra FG148A replacement, but YMMV.
live4theking
Old Man with a Hat
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I've got a spectra in my 68. When I first put it in the gauge would only go to about 3/4. I pulled it out and very slightly bent it down, not even a 1/16th of an inch. Now it goes above full and down to empty. I'm sure the meter match that Big_John speaks of is more accurate, but this is good enough for me.
330dTA
Senior Member
Following. I have similar problem. My fuel gauge is all right, it reacts when tested. My problem might be the float. Mine is a new repro sending unit, probably made in China, and I've heard those might have problems.
I bought the Meter Match, just in case. Better to be sure.
I bought the Meter Match, just in case. Better to be sure.
volksworld
Active Member
just pulled the sender out of my 68 today...it had stopped working over the 2+ years it took to get the engine back in...the plastic float had completely filled with gas...had bought a spectra one from autozone...couldn't get it to fit in the hole, as if the locating tabs were off a bit...gave up and stuck its float back on the factory sender, tried the new lockring it came with and that didn't tighten down enough...so wire wheeled the original and re-used that too...it all works fine now...so maybe your float has been slowly filling up all along
Thanks to all. Got under the car today with a spare sending unit from my collection of parts for my 61 Chrysler. I didn't install it in the tank, as it's not correct for the 70, but I wired it in and put it in the Empty, 1/2 way, and Full positions and the gauge read perfectly on the dash, so I'm convinced it's a sending unit/float issue. I need to burn off some gas before I can back the car up on ramps and remove the sending unit without gas coming out when I remove it to check the float, windings, and wiper contact. Thanks again.
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