I have a zafria that wont start. It has been in the garage, had the fuel pump off and tested, ok, filter and housing replaced, injector seals replaced, new glow plugs, pipes and joints replaced, filter in tank replaced and found oil in the fuel tank. After all this it runs for a few weeks and when you go to start again after overnight or a few hours, the engine turns over but no start. There is no fuel to the injectors. It feels as if the fuel drains back to the tank. Beginning to think there is a simple fault that escapes us. Where is the loss of pressure happening.