Fuel gauge was iffy "forever," but would come back in randomly; sometimes it would correct after going over a bump, sometimes after filling the tank, sometimes for no obvious reason. A few months ago, it suddenly started working again! Then, a mechanic noticed a thin hose under the hood somewhere near the crank shaft wire had disconnected. He reconnected it, and when I went to drive home, the gas gauge was out again, and has been since. :-( The odometer and speedometer have always worked.:-) Preparing for a 1200 mile ride southeast to northeast. Would be so great if the fix for this is simple....Also, mechanic suggested filling a gas can and storing it in the Uhaul trailer. Guy at Lowe's said that was a dangerous, terrible idea. Is it?

The trip odometer does not work, but I can note the mileage at each fill-up and figure how much I am getting per gallon as the trip proceeds. I appreciate the gas can safety perspective, and everyone's thoughts and advice all the way around.

Like the others said, probably not a quick fix. However, I never trust a fuel gauge anyway. Mine lies, like it was meant to: it tells me I am dangerously low on gas when I have two or three usable gallons left. It also appears that I burn no gas for the first 50 miles after leaving the station. That's just the nature of the thing.

What you should be using instead to plan gas stops and gauge mileage is the trip odometer. Find your average mileage. Figure on using about 12 gallons of gas between fill ups. You have a 15.8 US Gal tank, so 12 gallons is comfortable - you have plenty of usable fuel left in the tank, not stressing the in-tank pump. Your mileage times 12 gallons = how many miles between fill-ups.

My car averages 21 city / 25 highway. Knowing that, I fill up when my trip odometer hits about 240 miles.

It would be nice to have the gas gauge working, but you're not exactly running blind without it.

Also, "dangerous" is a relative word. I don't see how carrying a secured, extra tank of gas in a Uhaul is any more dangerous than the accessory gas can that Volvo used to sell to fit into the well opposite the spare tire in the trunk. Some people are just scared of gasoline. It's less dangerous by far than running out of gas in 100 degree weather. But then, you have no reason to be running out of gas.

It is probably the fuel sending unit attached to the tank, it holds the pre-pump and the float/fuel sender. The wires going into the unit rot off the exterior and stops working.
Dan

+1

I've seen this on two of the three 240s I've owned. In your trunk/hatch there will be a small square cover under the carpet, maybe 4 inches by 4 inches, held on by two screws. Take that off, and you can see the top of the gas tank and the sending unit. There should be two hoses or so coming off of it, and an electrical connector with a couple of wires coming out of it. I'd guess that if that connector isn't already broken off and hanging, just a light poke at it with your finger will break it the rest of the way off.

If you decide to replace the sending unit, I would strongly recommend spending a little extra to get the OEM unit. I have had nothing but bad experiences with the aftermarket units. Even with the OEM unit, look closely to make sure all of the wires are in the right place.
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1966 122s, 1968 142s, 1969 144s, 1979 245dl, 1989 244gl