GMC Repair: HARD START/LONG CRANK TIME, engine fires, gmc jimmy

Question
 ON A 93 GMC JIMMY, 4.3 VORTEC (W). WITH OVER 120,000 MILES.  HAVE BEEN EXPERIENCING A LONG CRANK TIME BEFORE ENGINE FIRES. REPLACED MOST COMPONENTS ON IGNITION SYSTEM EXCEPT FOR MODULE. ALSO REPLACED FUEL PUMP AND ALL FILTERS...REPLACED TANK ALSO (WAS LEAKING). IT EVENTUALLY STARTS BUT NOT WITHOUT YOUR PUFF OF BLUISH WHITE SMOKE. IT WILL START WITHOUT TOUCHING PEDAL BUT SEEMS TO PICK UP ON IDLE BETTER IF YOU GIVE A LITTLE PEDAL.  IT SEEMS TO ONLY DO IT AFTER IT SITS A WHILE LEANING ME TO BELIEVE THE FUEL PRESSURE IS BLEEDING OFF BUT I AM NOT AWARE OF CHECK VALVES IN THIS SYSTEM.  TURN KEY PUMP RUNS, START CRANKING PUMP CONTINUES TO RUN. WONDERING IF IT COULD BE ELECTRICAL.  IF YOU CAN HELP I WOULD APPRECIATE IT.
THANKS, BILL D.

Answer
You did not mention if you have:

1. Tested the ignition coil(s).

2. Checked for adequate fuel pressure and fuel volume. Just
  because the fuel pump is NEW, does NOT guarantee that it
  is 100% operational.

3. Tested the ignition module when the engine is at normal
  operating temperature.


Even if the fuel pump check valve was faulty and the fuel line drained all the gas back into the fuel tank, The initial 2 second run of the furl pump prior to starting the vehicle would fill the line and the injectors with adequate fuel pressure and volume.

Try this test:

When you are ready to restart the engine after it has reached normal operating temperature, Cycle the key 3 times to the ON then OFF position and then start the engine and see if it starts faster.

Let me know.


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