LHN...We ARE the Joneses
Pulling the power feed on the LP, and then measuring vacuum at the stock filter head at idle, IS a usable indicator of filter restriction. (2"Hg [fresh] vs 4-5" [end of life] )I was merely trying to explain that looking to see what your pressure is at idle does not give a good account of how restricted your fuel filters are.
Whereas added pressure could mask a restriction at idle.
Not really. With the easy $$ made over the years on fuel filter changes, I doubt that's what they were going for in the change up.I guess I will never understand why GM decided to suck the fuel from the tank to the CP3. Especially with the rail pressures the injection runs at. They finally wised up on the new L5Ps. Sucking fuel from the tank thru the fuel filter (especially a clogged filter) to the CP3 is just dumb. I work on many jet aircraft fuel and hyd systems. You always supply a main delivery pump with head pressure. Dean
They switched from Bosch to Denso to overcome the CP4 failures.
Bonus, that system utilizes a FWS filter/pump at the tank, with added ease in filter changes and positive pressure forward.
Also, comparing fuel draw pressure vs rail pressure....it's all about fuel volume, not pressure on the inlet. Not much of a comparison between 6psi on one side vs 26-30k on the rail.
Supply volume is key.