Hard Topping Up

[comprose]

Driving a 1999 30' Motorhome, Chevy 454 engine.
Except for the COSTCO gas pumps, I have a real problem trying to fully fill my gas tank. The auto-cutoff feature seems to be triggered way to soon. Just the other day, after resetting the cutoff three times, I still showed about 1/8th of a tank empty. Makes it hard to calculate mpg (I've got over the shock of mpg a while back after owning this rig for a year). Wondering if this is an inherent issue with this model.

[overlander63]

Originally Posted by comprose

Driving a 1999 30' Motorhome, Chevy 454 engine.
Except for the COSTCO gas pumps, I have a real problem trying to fully fill my gas tank. The auto-cutoff feature seems to be triggered way to soon. Just the other day, after resetting the cutoff three times, I still showed about 1/8th of a tank empty. Makes it hard to calculate mpg (I've got over the shock of mpg a while back after owning this rig for a year). Wondering if this is an inherent issue with this model.

It is the way the fill pipe goes into the tank. Try moving the handle toward the front of the coach, then the rear, until it doesn't auto-shut off as easily.

[idroba]

More than likely the vent hose from the tank to the filler inlet has slipped and is not draining back to the tank, so it is not venting correctly. Look for the small (3/4 inch diameter or so) line from the tank to the filler. Reposition it so it has no dips and a constant slope from the filler to the tank. Tie it into place with zip ties.

It is a fairly common issue with a lot of motorhome gas tank fill systems. I have had it both on an Airstream 310 and a GMC motorhome.

Costco has very slow fill pumps and probably the reduced volume in the main fill hose is low enough so it is venting back that way. Other, higher volume pumps, are probably triggering the issue, and need the vent hose to be empty of gas and only have vent fumes in it.