Re: 99 xj slow starting

Aug 26, 2003 4 Replies


Hi Kevin,


> They stick it in the tank:
>
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I th>>
>> My 99xj sport 4.0 liter has difficulty starting when sitting a few
>> hours. It turns over for about 5 seconds before it starts. I've
>> tried "priming" it by turning the key to the run position for a few
>> seconds until the pump shuts off then repeat and this seems to help a
>> lot. It starts quickly if I follow this procedure. Searching past
>> posts this points to a fuel pressure problem. I can't seem to find
>> the pressure regulator. I see a line going in the front of the fuel
>> rail but not a return line. Can anyone help me out?
>>
>> thanks. kevin.
  • * * Matt Macchiarolo
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So is this what maintains the correct fuel pressure while the engine's running or when it's shut down? I think I'm thinking of an anti-drainback type valve...

  • * * Matt Macchiarolo
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I'd check the fuel rail pressure and bleed down mainly for your safety. The pressure regulator is on the fuel rail on some models and in the tank on others.... but if that is all it is and the PITA factor is unimportant, no biggie. You'd want to make sure the pressure is actually high enough for operation and not too high so it may pop hoses. Two other things cause bleed down, leaking injectors and leaking hoses. Would suspect an injector leaking into the engine would show as black puffa smoke on restart, but some also leak around their seal. And a leaking hose between the tank and fuel rail can get interesting in a hurry. Could swear there is also a check valve at the pump even with the on-rail pressure regulator, but have no manual that shows either.

Approximately 8/26/03 12:54, L.W.(ßill) Hughes III uttered for posterity:

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