Thread: Fuel Gauge

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I've been helping a friend get his rod going. Just about finished the wires but he wants to retain the original SW gauges, not a problem except for the fuel gauge. Looking at the SW website they use(d) 3 different ohm ranges. Has anyone come up with a clever way to determine which range I'll need - at the moment I've got nothing - and purchase of 3 different senders isn't really an option.

If you can find an Part# of any kind on the gauge you might be able to match one up. I've run into similar situations over the years as Ford and MOPARs take one sender and GM another.....of course most modern aftermarket gauges use the GM one. If you have the old sender you might be able to get it working enough to read the ohms. The values you're looking for are Empty and Full, what it does in the middle doesn't matter for determining the sender you need.

Two options I can think of are:

Amazon. If you can find the sender listed there, they have a really good return policy.

The other is a little pricey, but there are various convertors/interface units out there that they claim to match the gauge to sender. They do various things; polarity, ohm changes etc so read the description closely. I've never used one so don't have any idea how well they work, but I think there are a few You Tube reviews out there.

https://www.google.com/search?client...auge+converter


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Wonder if a guy could wire a rotary variable resistor (rheostat?) to the gauge and adjust it to swing the gauge full scale, then keeping the dial fixed, disconnect and measure the resistance through the variable resistor? I've never done it, but it seems like it would work. That said, buying a variable resistor would be like buying multiple senders, so it's only an option if you've got an old rheostat laying around.....

Can you get to the sender and measure it while moving it through it's range?

Originally Posted by v8nutz

Can you get to the sender and measure it while moving it through it's range?

I believe the issue is that they have the old SW gauge, but no sender. Mike's looking for help finding the right sender out of three options for the old SW gauge rather than ordering three and trying to return two.

Yes, I only have the old gauge. And calling SW is just an exercise in frustration. they know NOTHING! First call the tech says they only used 1 sender for all their fuel gauges. That's odd I replied. I see 3 differing part numbers with 3 differing ohm readings on the website! SILENCE! The next call to SW the tech was blabbering nonsense.. remember that old saying "if you can't dazzle'em with brilliance, baffle'em with bullshit!" that was him and he wouldn't stop talking! I hung up. the rheostat idea is a good one but I haven't got or found a unit to test with. Mike P offers some possible solutions. I have the gauge number but SW doesn't know what sender goes with it.. or so they say. I think I could send it to Dakota Digital or the like and they can test it but the shipping could kill that idea. Can I say how much I miss Radio Shack!

How about an RV light dimmer switch? Maybe find a salvage unit, or visit an RV place and see if they have a scrap pile?
https://www.amazon.com/Dimming-Trail...8&gad_source=1

Just a thought Mike, if you or the owner happen to have an old "good" sender sitting around (like the universal ones that used to come with some gauges) or one from a car you could always wire it up and see if the gauge reads.

If it's a universal one it's most likely for a GM type gauge. If it's Ford or Mopar and the gauge works great, if it doesn't work then the gauge will probably calibrated for a GM type sender. If nothing else you may be able to figure out what it needs by the process of elimination.


The Ford and Mopar have just a little bit different ohm range but their close enough to work and today most companies seem to sell 1 sender or gauge and it's close enough to work (but may require bending a arm a bit). Back in the old days SW probably listed separate senders for Ford and Mopar which is why they list 3 sending units.



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This is what I found on ebay

https://www.ebay.com/itm/13507208001...Bk9SR6yr1f-cZA

Mike, I wonder if back in the day SW sold 3 different senders, aiming at the guys who were hopping up an old GM, Mopar or Ford using the stock gauges but a new tank? That could make what the SW tech said, "All SW gauges use the same sender..." a true statement.
I don't know this to be true, just looking at options.

Um… I guess it’s all in the presentation! But when you’re using a SW gauge and you have their number. I’d expect that they would have a idea what drives it!

"..... I guess it’s all in the presentation! But when you’re using a SW gauge and you have their number. I’d expect that they would have a idea what drives it!....."

You'd sure think so. I think one of the problems we old timers run into is that we (and a lot of the parts we deal with) are from an age of catalogs and parts/tech people who were car guys.

Fortunately or unfortunately depending on your perspective, we've lived long enough to be in an age of computer operators and if it ain't in the computer it doesn't exist.

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I'd call Speedway. Their techs seem to be better at old stuff than most.... or maybe call Dakota Digital and see if they know.

likely a 30 or 90 ohm gm sender. see if a parts man will let you test.

Originally Posted by rspears

I'd call Speedway. Their techs seem to be better at old stuff than most.... or maybe call Dakota Digital and see if they know.

Great minds think alike! I was thinking the same thing, they may know a thing or two if I can connect with the right person. Both DD and Speedway