Question: I have 1985 classic motorhome with a 460 motor. My problem is there are 2 fuel tanks for gas. The rear tank works fine, but the front does not. When running on the front tank on a flat road, things run fine. But when on a hill, it wants to backfire and stall.
So I then switch over to rear tank and I am off and running again. When I am on flat road again I switch back to front tank and I am alright again.
I have had a new pump installed in the tank and a new vent installed. It still does the same things and at this point I don’t know what to do next. Do you have some ideas?
Answer: Interesting dilemma. There are a few things that can go wrong with a fuel tank. Since you have replaced the most obvious culprit (fuel pump) then you should start asking whether this happens when the tank is full, half or near empty.
If the problem happens all the time regardless of fuel level, then you might have something clogging the fuel pick up. Have you inspected the tank?
If it happens when you are low on fuel, then it might be that a baffle has collapsed. Most fuel tanks are built with baffles to prevent fuel from sloshing around in the tank. It could be that when you are on an incline the fuel pump is left dry. Baffles prevent the fuel from accumulating in one particular place. Letting the pump run dry could be very detrimental to the life of the fuel pump if it needs the fuel to keep it cool.
Those are our thoughts on the subject. Other input welcome. Hope you resolve your issue and please let us know the outcome.