How much fuel do you really have left when that fuel light comes on

When i ran out the gauge said about a 1/3. Don't trust your gauge

 

I never trust the gauge in my Pete 389. I write down the odometer reading when I fuel. It averages 6 mpg so I just do the math.

Or, if Big Maude is around, I just have her shake the truck up and down. The Big Maude shake is accurate to a gallon or two give or take. The down side to the Big Maude shake is she’s been known to pop an air bag or two.

 

In my last few years driving I never really cared about my fuel levels. I know that sounds reckless and maybe it was. The thing is my carrier had my milages and set my fueling solutions based on my range and my expired miles. As long as I hit my fueling stops set up for me I would never run out of fuel. There was one exception to this. When I had an extremely heavy load and could not put a lot of fuel in my tanks. Then I watched my milages close and as soon as I could I topped off.

 

You old reckless devil you. I’d have never thought it of ya.

 

Quarter tank is as low as I like to let it go. Lowest it’s ever been is a hair above 1/8 had a beer load that had me barely legal at half tank had to keep my eye on how much I put in and fuel stops were far between.

 

Here is a dirty little secret that most people don't realize. Top off your tanks once. Refill between 1/2 and 1/4. Never go below 1/4......ever! Your fuel bill will be the same if you fill every 50 miles or every 800 miles. I know......Captain Obvious!

 

The 2021 Cascadia that I recently drove had two 120 gallon tanks. My low fuel light would come on when I still had over 60 gallons left or approx. 400 miles of driving. The first time I had the light come on I panicked & stopped for fuel. I later realized I had lots of fuel left. I still didn't like seeing the warning light but then again I'm a pilot & low fuel in an airplane doesn't mean just pulling over!

 

Many of the electronic trucks measure fuel burned. My last Volvo let me see miles & gallons since last fuel up while I drove. My last Frunkshirker & KW bury the gallons consumed in a menu that is only accessible when parked.

I find the low fuel light in my last several trucks comes on with well over 1/4 of fuel tank capacity, usually even more than 1/4 remaining, still available. I find counting the gallons burned and or tracking miles since full are better than looking at the fuel gauge. The fuel gauge is hardly useful. I would routinly use everything but the last 30 gallons. I once used all but 15 gallons. It's best if you always fill up and/or fill up in the same way. For example, either always squeeze every drop into your tanks that you can. Or, fill it until the foam get to the filler next. I found The difference betwen "every single possible drop" and "first foam" was 5 gallons or less. The time spent squeezing in the last 1-5 gallons was not worth it to me.

Everyone should run their own experiment because one day you will need to run it in real life.

 

My question is.....why run your tanks so low? What is the point? You are going to spend the same amount on fuel if you fuel every 100 miles....or every 1000 miles. Can anybody burn 200 gallons of fuel in a single drive shift?? Yes...Heavy haul drivers and the sort.....but run of the mill OTR Driver.....I think not.

 

There is something about low fuel levels that must be brought out. I am not speaking to the veteran drivers right now as much as the new drivers with 2 or fewer years. If you have an APU-equipped truck the fuel reed does not go all the way to the bottom of the tank. There is a reason for this. As with reefer tanks, the bottoms are full of crap. I once had a shop boss explain it this way. There is unusable fuel, then there is usable fuel, THEN there is unusable usable fuel. Depending on the size and shape of your tanks I would highly advise against going much below 4 to 6 inches showing. I have seen both tractors and reefers shut off because of clogged fuel filters that require the filter to be replaced and the fuel system to be re-primed. This causes needless expense and time broke down and is in almost every case preventable. Don't play games with low fuel!