2006 TL140 hard to start

[WillardNelson]

Been trying to diagnose a hard starting issue. My compression is good, timing is correct, no restriction in fuel lines, new fuel filter, screen on pump inlet is clean, good electric lift pump, fuel shutdown solenoid is opening all the way. It acts like it's starved for fuel if it sits for an hour or two. On the return line coming out of the injection pump, should there be some sort of a check valve to hold fuel in injection pump when not running? My fitting just has a small hole, no check valve or nothing going straight to the tank. Thanks.

 

[Tazza]

Does it puff smoke when trying to start? If it blows white clouds, you have fuel and compression, but may not have enough heat to ignite the fuel.
If you suspect air in the system, I'd open the line that goes back to the tank. try to re-prime it and look for bubbles, if there are bubbles, you have an air leak.