Dodge 2004 Quad 4x4 1500

IMHO only experience will tell you what the guage reads... I've found way too much variance between different trucks and cars (of the same model) to be able to accurately tell what the fuel levels are.

Maybe one of these days auto makers will come up with a weight based strain guage system to measure fuel levels!

That would work great on a bumpy road:)

With computers to smooth and process the data, it would not be difficult at all.

A simple accelerometer could be used to counter the effects.

I'm just as sure it can be done in software... Regardless, it is a pipe-dream at this stage, won't happen.

The best way to find out is run it down to 1/8th of a tank and take it to a gas station. Slowly put gas in it until the gauge hits the 1/4 mark and check the gallons readout on the pump. The tank isn't symmetrical so the number of gallons between marks will be different at different fuel levels.

Problem with this is that Chrysler filters the gauge readings (all of them!) through the PCM. This creates two problems:

1. The reading takes a while to stablize (done to prevent the needle from moving as gas sloshes around as you are driving) and,
2. Once you open the cap with the key on, the PCM detects an evap error and can set a code (OK, the code is trivial, and will eventually clear on its own.)

The first problem above is the more serious one. Easier to do is to do this in three steps..

1. Get to 3/4 tank, and fill it to the recommended level. Get the owner's manual and check how much the tank holds (usable volume). Subtract what you put in from the full tank amount, and that's what remains at 3/4 tank.

1. Get to 1/2 tank, and fill it to the recommended level. Subtract what you put in from the full tank amount, and that's what remains at

1. Get to 1/4 tank, and fill it to the recommended level. Subtract what you put in from the full tank amount, and that's what remains at

1. Get to 1/8 tank, and fill it to the recommended level. Subtract what you put in from the full tank amount, and that's what remains at

Takes four trips to the gas station, and a bit of simple math, but it will be more accurate than tryign to wait for the gauge to stablize as you are filling.

That's why I said slowly. I re-fuel my '99 by watching the fuel gauge every time. I re-fuel from my garage and my nozzle doesn't have an automatic shut-off. When it gets close to the full mark I slow the pump down. When the needle is just above the full mark I shut it off. I've never over-filled it.

I don't think it'll set any codes if you take the cap off with the key on (engine off). The PCM controls the evap purge solenoid based on engine operating conditions. I think the PCM knows when the engine isn't running, but I could be wrong.

i think i need a nap after all that addiplicating.

i have ~280k on my daily driver and have never even thought about this conundrum. when my truck get to a quarter tank i fill it back up. if you drive around with much less than a quarter tank in the 100 degree georgia hot sun for long you get to put in a new fuel pump more often than you would like. michael

same routine here. i buy all my fuel in bulk for the convienence of not having to stop at places where i am not sure of their storage tanks. i did just buy a nozzle with an automatic shut off so that i don't have to worry about employees accidentally pouring my fuel out on the ground.

not to mention that i have discovered that about 20% of the local bp/amico stations are not actually putting bp branded gas in their tanks. several of the pakistaniranian owners are actually selling the off brand and blended stuff from the hub to make a couple of extra cents. michael

I don't worry too much about that. I make my own fuel.