Quote:
Originally Posted by dieselbenz1
While waiting on starter parts I pinched off the fuel return line, connected a pressure pump to the inlet of the lift pump and am unable to establish any pressure on the fuel system. More digging into this as I would like to bleed out the fuel system with all the up coming cranking.
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The 603's will not build pressure in the fuel system like the 617's will. They don't use a strong spring in the check valve on the IP and also have a bleeder port in the fuel filter housing. The overflow valve on the back of the IP is a metered orifice and has a very weak spring on the check valve portion, it is fuel flow against the orifice that builds pressure in the system, not the spring tension like the 617's. If you moved an adequate amount of fuel through the system, you would develop pressure against the orifice.
As for priming the system, I've had good luck unbolting the lift pump and cycling the plunger several times. The lift pump moves quite a lot of fuel on these engines (far more than the 617's) and it doesn't take a lot of effort to fill the filter and fuel rack.