1999 jeep fuel problem


Old 07-28-05, 06:58 PM
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1999 jeep fuel problem

I have a 1999 Jeep Grand Cherokee 4.0liter,V6 Auto trany.
If the vehicle is left to sit over night it takes about 15 seconds of cranking before it will start. But if you have already ran it in the last hour or so, it will start up right away. I checked the pressure at the fuel rail, and over night there is nothing, and if it had just been run, lots of pressure. Some how the fuel is bleeding off. Can anyone help.
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Old 07-28-05, 07:41 PM
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Check the fuel pressure regulator, also the fuel pump could be getting weak.
This info applies to a 90 inline 6cyl - maybe its' the same for yours
Old 07-29-05, 07:52 AM
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I replaced the fuel regulator, and nothing changed. I have heard that it could be the fuel pump. Thats a 600$ job. Thanks.
Old 07-29-05, 04:24 PM
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Run across this many times on Jeeps.. There is a check valve on the top of the fuel pump assembly/module. It's supposed to keep the fuel pressure applied to the fuel rail. Only fix I've ever been aware of is replacement of the entire assembly. I had 1 jeep it took 6 pumps to finally get 1 that worked correctly..2 Napa's and 4 Chyslers..A way to confirm this is attach your fuel pressure gauge to the rail, cycle the key a few times to built the pressure to normal, and then pinch off the fuel line... If the pressure stays, it's the pump assembly..if it drops, injector(s) are leaking..
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