I have an on going problem with my 1974 240D that the engine will not start. The engine had been running without any problems and was running OK when I left it parked at the airport for 5 days. When I got back it would not start. I had it towed to the shop and was told it had a leaky fuel line which they repaired and the car now starts fine. I picked the car up and drove it around some for the rest of the day. It started fine each time I started it. The next morning again it would not start. Back to the shop it went. Now the problem is supposed to be a bad lift pump. Replace the lift pump. Side note, just try and find a lift pump for a 1974 240D!! The car is running fine "again". I picked it up and again drove around some for the rest of the day, starting and stopping without any problems. This morning it will not start again.

The battery is charged, the fuel tank is full, and the starter and glow plugs are OK. When I use the hand primer pump I see some bubbles in the clear plastic fuel filter. I loosened the connection on the main filter and pumped but did not see any air bubbles come out. If I continue pumping the primer pump until the injection pump value starts to click, the bubbles in the clear filter seem to be gone. The car still will not start. Any ideas or suggestions from anyone? Is more information necessary to make a diagnosis?