sounds like fuel pressure issue...not easy to diagnoise ..can be multitude of things .is the primer screwed fully in ?no blockages in he fuel pipes ? pressure retention valve on front of upec may be faulty ,injectors,or ,anyone of he pump units ,which there is no test for .is filter housing ok ,is the filter ok...you need to connect gauges to check under pressure and fuel pressure..try disconnecting return pipe at chassis and see if it starts any better
norb
March 2013