Both my Isuzu Pup diesel and my Trooper TD have the same exact problem: If there is less than a 1/4 tank of fuel and I park for more than 4 hours on a hill (with the engine facing uphill), it won't start. I have to push the car to level ground and then suck fuel back up to the filter to get it to start. All the lines seem tight and I don't have any fuel leaks. Any comments?

Steve--

Your symptoms are those of an air leak somewhere in your fuel system. Pretty much does not matter where it is. Many times air can be sucked into a small leak where fuel does not come out. And, when air is allowed in, it rises to the top of the system and the fuel that was there drains back to the tank.

It is tedious to find these most times. Could be a loose banjo bolt or an old and porous fuel line. And, it doesn't matter whether it is in the fuel feed or the fuel return.

Or, worst case you could have an air leak in your injection pump. This would call for dissembly and installation of all new seals. Fairly big deal. Look real hard for the other stuff first.

Paul

PS-- NCDiesel had a loose banjo bolt at the pump fuel inlet and he could not start his brand new rebuilt engine on the flat. A hill would be worse.

I've heard of that happening. --He's right.