Like most people, I'm tired of the hoky fuel gauge readings which seem to follow no rhyme or reason. So I took up the floorboards and played around a bit with the vents. Basically, it has a weird arrangement.
The left side tank (non-filler) is vented through a hose and orifice and contains sender for the gauge. The right side has the filler and also accepts the fuel return from the injection rail. I didn't measure it, but most CAT engines (with which I'm very familiar) that use this type of indirect injection recirc a large amount of fuel- something like 80% of the lift pump total for injector cooling. The two tanks are connected by a 1 inch hose and a smaller 5/16 suction hose that is t'ed to the fuel pump. In theory, if the left side vent works then the two tanks should equalize through the connecting hose. But in short, they don't.
So I decided to swap them. Routing instead the return to the left tank and venting the right (which it doesn't really need since the cap is vented). Guess what, within 20 minutes of running the level stabilized and now tracks just like any auto fuel gauge. I'm still perplexed since this shouldn't have worked. But it sure did.
My guess is it has something to do with the left tank vent not relieving properly and preventing fuel flow into the tank. With this new setup, it is constantly being refilled by the recirc line and then flowing out to the right tank.
Can someone else try this and see if it works for them?
The left side tank (non-filler) is vented through a hose and orifice and contains sender for the gauge. The right side has the filler and also accepts the fuel return from the injection rail. I didn't measure it, but most CAT engines (with which I'm very familiar) that use this type of indirect injection recirc a large amount of fuel- something like 80% of the lift pump total for injector cooling. The two tanks are connected by a 1 inch hose and a smaller 5/16 suction hose that is t'ed to the fuel pump. In theory, if the left side vent works then the two tanks should equalize through the connecting hose. But in short, they don't.
So I decided to swap them. Routing instead the return to the left tank and venting the right (which it doesn't really need since the cap is vented). Guess what, within 20 minutes of running the level stabilized and now tracks just like any auto fuel gauge. I'm still perplexed since this shouldn't have worked. But it sure did.
My guess is it has something to do with the left tank vent not relieving properly and preventing fuel flow into the tank. With this new setup, it is constantly being refilled by the recirc line and then flowing out to the right tank.
Can someone else try this and see if it works for them?
