The in tank unit is only a fuel gauge sender and a tube for fuel pick-up.
The system uses the injection pump [CP3] to pull the fuel from the fuel tank, through the filter and FICM. Any small leak will allow the pump to suck air, and little fuel. The Filter head seals are cheap from a supporting vendor [GM does not service the seals] and easy to replace. Good place for any one to start when haveing a starting problem.
The LB7 engine -[01-04] has had some injector problems, and one is excessive leaking/passing fuel by the inter seals. That can cause hard starting when warm, but starts OK when cold, because the fuel is more dense when cool. The engine needs around 5,000 psi to start. A injector return test will show if you have a injector problem.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.--- Jerry
Last edited by jc1843; 11-29-2012 at 07:07 AM.