96 Chevy K1500 5.7L Rough Start Issue
New here although I have been trolling around reading threads. I have a current issue with my 96 K1500 5.7L. I have found that the engine has to crank over several times to strat, mostly in a cold state. Occasionally after sitting for several days or a week the truck with fire right up on a normal key turn. Over the past year I have done a lot of work on the truck to take care of other issues not relating directly to a hard start condition, although the hard start has been a lingering problem for a while. So here goes the list of items installed in the last 6-12 months:
-All new plugs - gap checked 100%
-Cap, Rotor and wires replaced as standard maintenance
-New fuel pump and sending unit
-Poppet valves replaced with upgraded MPFI unit to stop random missfire
-Fuel Pressure Regulator replaced at time of MPFI conversion
-Intake Maniforld and plenum gaskets replaced at time of MPFI conversion
-Crank Position Sensor replaced due to cracked housing
-Fuel filter replaced
-Seafoamed through intake and injection cleaner run
-Cats replaced as manifold was rusted through
-Ground wires checked on engine and at fuel pump
-Checked coil resistance per hanes manual standards - OK
I also notice that the engine idles rough for a few seconds after the vehicle starts, which indicates to me that there is still a fueling issue. But I can't seem to pinpoint it. I get no CEL other than a Bank 2 sensor 2 low voltage O2 sensor (replacing today), however all of these conditions were present before the O2 code.
Its been a while since I have checked my fuel pressure, but as I recall before and after all of the fuel components I had mid 50's fuel pressure when the engine was primed. Interestingly the fuel pressure drops off after the prime run, which I would assume is a FPR issue, but this is the 3rd FPR since the issue. Also, the same condition of fuel pressure drop occured before and after the MPFI conversion, fuel pump, sending unit, fuel filter, etc. I have the ability to data log through the OBDII if someone knows what spark advance, fuel trim, etc. should be. I can provide that info.