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Old 11-10-2014, 09:08 PM   #17
porky69
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Join Date: Aug 2011
Location: Coaldale
Posts: 89
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In a perfect world, yes but the world is not. Fluids follow the path of least resistance and therefore draws and returns may not be equal. On my Peterbilt the only way I could get the tanks close to the same level was to close, ever so slightly, the shut off valve on the return line at one tank (the one that is fuller), over eeveral tanks until they stay even.

In my opinion, and I have no solid facts to back it up, but with fluids following the path of least resistance, when you are travelling down most highways the main (right hand) driving lane is crowned to the right (ie your coach is leaning slightly to the passenger side), therefore the fuel on the uphill side would be the easiest to draw (suck "downhill" by the pump) and the return fuel would flow "downhill" easier to the passenger side, resulting in your scenario of passenger side fuller than the drivers.

Another possible source of imbalance is plugged/partially plugged tank breathers (may be separate or built into the caps) and if there are extension hoses on the vents they need to be equal length as well. This may explain why the generator only draws one side. Here is a link to a guy with an extreme case of fuel imbalance
Fuel tank problems 2004 century freightliner

I have experienced this as well. If this is the case the breather on the full tank would be the plugged one, it would be like trying to suck liquid out of a glass bottle with your lips tightly wrapped around the opening, you will get a little out but not much.

Here is a technical paper on dual draw fuel systems http://www.google.ca/url?q=http://ww...21nkRsOckSERkQ
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2007 Haulmark 3329DS, Freightliner Coronado Chassis, 515hp Detroit, Meritor Freedomline 12speed Autoshift, 10kw Generator, In-motion Satellite.
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