36 gallon tank
07-27-2011, 03:08 PM
#21
Originally Posted by VolFire
The computer and gauge are off by a little. This is very noticeable in larger tanks, on our ambulances (55 gallon tank) are notorious for inaccuracy. Check this link for why. A very good RELIABLE source (Discovery Channel) explaining, tanks, gauges and even the microprocessor gauges we have.
http://auto.howstuffworks.com/fuel-gauge.htm
Also a key factor to this equation is that tanks are not all accurate in production. Manufacturers give you the approximate tank size which is calculated by averaging multiple production units. Your 36 gallon tank could be anywhere within a margin of error. Could be 37 could be 38. Just means that there were enough 34 gallon tanks that came out to bring the average to 36 in production when they did the tanks for the 2009-2011 F150 body style...
07-27-2011, 03:15 PM
#22
Senior Member
Its the same part of the computer that calculates your MPG. It doesnt read exactly how much gas is being used and doesnt measure what leaves the tank per se, it estimates based on the readings that it gets from the microprocessors in the tank regarding fuel level and calculates that it has what *should be* left based on the premise of a true 36 gallon tank, your miles traveled as reported by the odometer and MPG. Which is an estimate. Reason why the "feed me" chime goes off at 50 miles. Gives you plently of buffer to find fuel since you probably dont really have 3 gallons left of usable fuel. I was returning from a trip the other day and got to my parking lot just as the chime went off and then my phone rang. During the 5 minute phone call I went from "50 mi to E" to "32 mi to E". I didnt burn 2 gallons of fuel just sitting there in 5 minutes...
Last edited by VolFire; 07-27-2011 at 03:19 PM.
07-27-2011, 04:44 PM
#24
Senior Member
It is probably a combination of a number of factors namely, inaccuracy of the fuel pump and the fact that the gas tank isn't exactly 36 gal + capacity of the filler neck. The expansion theory is nice but doesn't hold water since it would expand in the fuel tank after it was pumped. Measured volume is measured volume. Gas should be sold by weight to negate any temperature effects on volume.
I am an automotive engineer and although I don't design fuel tanks I do write the tests that check the fuel vapors that they produce for OBD compliance. Every fuel tank has a vapor dome. As the fuel gets hot and expands it produces vapors that need somewhere to go. When the engine is running the vapors are circulated back into the intake via the canister but when the vehicle is shut off just soaking in the heat you need this.
07-27-2011, 05:16 PM
#25
Originally Posted by shortride
It may have more to do with the fuel tank not having exactly 36 gallon capacity. Anyone that runs their fuel tank completely empty needs their head examined.
07-27-2011, 05:23 PM
#26
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How expensive do you think a fuel pump costs? Keep running it low and you'll find out
07-27-2011, 06:05 PM
#28
Originally Posted by Night_Wolf
How expensive do you think a fuel pump costs? Keep running it low and you'll find out
07-27-2011, 06:45 PM
#29
You americans are lucky. Gas costs 1.34 per liter where I live for regular. That works out to be over $5 a gallon. A lot of people cross the border just for gas.
Why wait to be almost completely empty before getting gas? Yes warranty would cover it but it's a hassle.
The computer isn't always %100 accurate. Pump could be off too. I never wait until I hit E for gas just in case the needle/computer is off. Not worth the risk.
Why wait to be almost completely empty before getting gas? Yes warranty would cover it but it's a hassle.
The computer isn't always %100 accurate. Pump could be off too. I never wait until I hit E for gas just in case the needle/computer is off. Not worth the risk.
07-28-2011, 10:06 AM
#30
Called the dealer about this and spoke with who knows who in service. Guy tells me that the gallons used is a guess and can be 20% off. That is around 7 gallons that it can be off. I don't buy it!
If Ford can't accurately determine the gallons used then they should remove that technology feature as it isn't anything to trust nor even pay attention to. The need to figure out how to measure the gas that leaves the tank. A pump at a gas station can measure it, why can't they put that age old technology in an advanced truck today.
If Ford can't accurately determine the gallons used then they should remove that technology feature as it isn't anything to trust nor even pay attention to. The need to figure out how to measure the gas that leaves the tank. A pump at a gas station can measure it, why can't they put that age old technology in an advanced truck today.