extended cranking

[trashman1980]

i have a 98, it has an extended crank before starting and when it does start it will barely start and sputter abit, but some times it fires right up. any ideas? oh the fuel pump is only 1yr old.

 

[MustangLX-5.0]

How long ago did this extended crank issue start? And when you say "extended" how long do you mean? Normally when the engine hasn't been running for say..a day, if you don't crank long enough and just think the engines about to catch and you let the key back, it will typically (attempt) to grab and then sometimes sputter or make a funny "Phughhh" noise from the intake, then you just didn't crank long enough. When the engines been running for at least 15 minutes and then you shut it off, wait a min then start it, it should start right almost immediately. Cold starts generally take 2 - 3 times as long as a warm start.

Pushing that out of the way, check your fuel pressure. If you don't have a fuel pressure gauge, just run to Advanced Auto or Autozone and (borrow) a gauge. You should be able to check the pressure out in the parking lot. Running pressure at idle when cold should be between 28 - 34psi. Raise the engine speed or blip the throttle plate hard but quickly. The pressure should momentarily increase to near 40 psi then slowly fall. Now, as the engine idles, removed the vacuum plug from the fuel pressure regulator and monitor the fuel pressure. The pressure should increase to near 40. If none of the above readings are anywhere's near what your results are, (eg.. the pressure is excessively low) then you have a problem with either the pump or the regulator. Check the regulator since you already replaced the pump.

Does it run rough in any way? Whats the mileage?