How does my truck know how much fuel the engine is using. How accurate is it?

Thanks,

Ryan

Not very accurate. Mine is always says I use one more gallon per tank than I did.

It doesn't have a fuel flow meter. It calculates fuel use based on fuel pressure and injector open time. Same way as it works on fuel injected gas engines.

it seems like a flow meter would be a much easier way to track. This must be why it is not very accurate.

Thanks,

Actually noted mine on the last few fill-ups and believe it or not it was only .1-.2 10ths off. Filled up with 19.8 gal on pump and DIC read 19.6 used? And I am even running Triple dog in exteme setting. I get the most accurate fills by "slow filling" (to avoid foaming) to the top of the neck every time. I am sure that at the first auto shut-off is different from pump to pump. So I try to stay as consistent as possible.

A real flow meter would be much more expensive. It dosen't cost anything to do the math and calculate a ball park value since all the required measurement paramters are already available to the computer anyway.

A flow meter would be of no use since the portion of the fuel not injected is returned to the tank.
It would show that fuel is flowing in the pipe but that does not represent what is actually used by the engine.