Long crank on a '99
02-14-2012, 11:55 AM
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Year: 98
Model: Cherokee
Engine: 4.0
Long crank on a '99
Buddy's neighbor has a 99 4.0 that has a long crank time. He's replaced the fuel pump and filter and still the same condition. It does fire up right away if he has the KOEF(key on engine off) for over 10sec.. Any ideas? Thanks
02-14-2012, 12:07 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
He is experiencing a "pressure drop" if priming it with key-on, key-off enables a quick start.
If he only replaced the pump, time to go back in and replace the rest of the assembly.
Otherwise, there could be a fuel system leak anywhere between the tank and the injectors that is responsible for the pressure drop.
If he only replaced the pump, time to go back in and replace the rest of the assembly.
Otherwise, there could be a fuel system leak anywhere between the tank and the injectors that is responsible for the pressure drop.
02-14-2012, 05:15 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
Another very pertinent question.
But keep in mind that the pressure leak can occur anywhere along the entire fuel delivery route.....
When it starts, does it start CLEANLY, or does it stumble for a few seconds? If it stumbles, it could be a leaky injector. They can drip raw fuel into the cylinder which results in both a pressure drop and a rough start for the engine.
But keep in mind that the pressure leak can occur anywhere along the entire fuel delivery route.....
When it starts, does it start CLEANLY, or does it stumble for a few seconds? If it stumbles, it could be a leaky injector. They can drip raw fuel into the cylinder which results in both a pressure drop and a rough start for the engine.
Last edited by tjwalker; 02-14-2012 at 05:19 PM.
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Often a long crank is a sign of a fuel injector that is "leaking down"..That is it is stuck partly open.
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