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brownjeff, ASE Certified Technician
Category: Jeep
Satisfied Customers: 13886
Experience:  17 years experience, ASE certified, dealership certified, Service Manager for 15 years,
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Jeep Grand Cherokee Laredo: Need fuel pressure with KOEOff

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Need fuel pressure with KOEOff and KOEOn.....also what pressure should it hold while running?

2002 Jeep Grand Cherokee 4.0
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  1. Start engine and bring to normal operating temperature.
  2. Observe fuel pressure test gauge (or DRB screen). Normal operating pressure should be 339 kPa ±34 kPa (49.2 psi ±5 psi) .
  3. Shut engine off.
  4. Pressure should not fall below 30 psi for five minutes .
  5. If pressure falls below 30 psi , it must be determined if a fuel injector, the supply check valve within the fuel pump module, the fuel filter/pressure regulator, or a fuel tube/line is leaking.
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Customer: replied 5 years ago.

Should the pressure ever fall to 0 while it is NOT running.


Had a long start constantly and the fuel pressure was dropping.....changed the fuel pump and fuel filter and still has same problem


There is no spec. on this but typically there is always pressure in the system and if your loosing pressure and have replaced the pump already you most likely have a leaking injector/s