Hi we have a very old Daff (1996) that?s decided it didn?t want to start. We have replaced the seals in the separator, and suction side connectors on the file line at that end, replaced the fuel pump (lift pump) and fuel filter and we seem to have a good flow of fuel to the injector pump. We also have voltage to the cut off solenoid which is also new ish.It seems like it?s just trying to start but can?t quite make it so we?re suspecting a tiny air leak. Any pointers or ideas would be great. Thanks