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Unread 07-22-2011, 02:22 PM   #1
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1997 ZJ 
Join Date: Jul 2011
Location: Maize, KS
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Fuel pressure test port sprays air

97 Jeep Grand Cherokee with 4.0L. I have been having problems with intermittent sputtering and stalling under load. To check for fuel pressure I pressed in the shrader(test port on fuel rail) valve and noticed a spray of fuel and air rather than a solid stream of fuel. Is this common? Also, no codes have occured which is odd and makes diagnosing the problem VERY difficult.

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Unread 07-22-2011, 10:52 PM   #2
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Did you check the pressure with a gauge? There will be a quick shot of fuel if you just press the valve, but not a constant flow. As far as the air, not sure. Don't remember if your '97 has an inline filter or not, but if it does, when was the last time you changed it? Post up your pressure readings. BTW, leave the gauge hooked up and shut down the Jeep. Wait a while and make note of pressure drop, shouldn't be significant.
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Unread 07-22-2011, 11:54 PM   #3
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1997 ZJ 
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Location: , Pennsylvania
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97 doesn't have an inline filter.
you need a gauge, just hitting the valve core doesn't tell you much other than there is gas there.
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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Unread 07-23-2011, 04:59 PM   #4
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1997 ZJ 
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I have measured with a gauge and read 45psi with engine running. Fuel filter is part of the fuel tank module and was changed with fuel pump. And pressure is maintaned for awhile after shutting off engine.
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Unread 07-23-2011, 09:42 PM   #5
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What brand of fuel pump was used as the replacement? Personally I doubt that its the fuel filter, I recently discovered that my fuel filter was likely more then 10 years old after I ended up cutting it out of the bracket and the only symptoms I had was that I had to shove the pedal harder to accelerate, and mileage sucked. 45 Psi sounds a bit high though, but they might have changed the specs between the 4.0 and the 5.2, or 93-95 and 96-98.
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4.0l , fuel , pressure test , stalling
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