Fuel tanks

What year truck? Fuel gauges are not accurate at all once you get below half tanks. I have a 98 and when it shows less than 1/4 tank or even empty I still have 50-70 gallons. New float didn’t change it.

 

I wouldn't want to take the tank any lower than 30 to 45 gallons anyway, you don't want to run out.

 

Lots of trucks have different size tanks . I have 2-135s but the passenger side is split between fuel/hydraulic…. And it’s fine

 

Test the float. Just like an old school carburetor float the arms can be adjusted by bending the rod the float is on. They can be fine tuned. Fill it half full and see what it reads. Get a wood yard stick to stick in tank to get a rough measurement of where half should be. Check gauge and see where the needle sits. Pull sender out and adjust rod accordingly to get gauge to read half. That should make it pretty darn close to as accurate as possible. Watch it as you drop to quarter and yard stick it again to check level to gauge. Fill tank to 3/4 and stick it again. Then full. Pull sender as many times as you have to and adjust till its right. Sounds like ADHD Piece of mind but it’s good piece of mind. Inaccurate fuel gauges are a pet peeve of mine like oil leaks or dirty chrome. Lol

 

I have 2-90 gallon tanks.I've ran it down until I get a low fuel light,but it only takes 120 gallons to fill it at that point.Im assuming I have 30 gallons left in each tank.Winter is coming so I always stop for fuel when I'm down to 1/2 tank on the gauge.It usaully burns 80 to 90 gallons a day.2021 Freightliner, DD 13 automated.

 

If the gauge isn't accurate. The tank is probably in the wrong position.

The sending unit should be on top. 12 o clock. I think the tank vent also sits the same.

If the filler hole sits on top. It's in the wrong position. Should be about 11 o clock. Ish.

I don't know what the float looks like but I'm guess it's a float that moves up and down. Along a straight shaft.

Not a arm type system. That hole the sending unit fits through is pretty small. Be tought to fit a arm through there.

 

I figure I have around 80 gallons left in my newer T680 (120-100) when the light goes off. That's an annoyingly huge number, but I figure this may have something to do with semi's having problems maintaining flow on steep hills, running tanks dry is very bad, or both?