Jeep 1996 Grand Cherokee Service Manual - page 1052
(3) If pressure is at O psi, connect DRB scan tool
and refer to operating instructions in the appropriate
Powertrain Diagnostics Procedures service manual.
(4) If operating pressure is above 51.0 psi, fuel
pump is OK but pressure regulator is defective. Reg-
ulator is not serviced separately. Replace fuel pump
module assembly.
FUEL PUMP PRESSURE TEST—5.2L ENGINES
WITH PRESSURE TEST PORT
NOTE: The fuel pressure test port is used on cer-
tain engines only. On 5.2L engines, and when
equipped, the test port will be located on the fuel
rail near the throttle position sensor (Fig. 9). A seal-
ing cap is screwed onto the test port.
All fuel systems are equipped with a fuel tank module
mounted, fuel pressure regulator. The fuel pressure reg-
ulator is not controlled by engine vacuum.
With engine at idle speed, system fuel pressure
should be 338 kPa
6 14 kPa (49 psi 6 2 psi).
WARNING:
DO NOT ALLOW FUEL TO SPILL ONTO
THE ENGINE INTAKE OR EXHAUST MANIFOLDS.
PLACE SHOP TOWELS UNDER AND AROUND THE
PRESSURE PORT TO ABSORB FUEL.
WARNING:
WEAR PROPER EYE PROTECTION
WHEN TESTING FUEL SYSTEM PRESSURE.
(1) Remove the protective cap at the fuel rail test
port. Connect the 0–414 kPa (0-60 psi) fuel pressure
gauge (from gauge set 5069) to the test port pressure
fitting on the fuel rail (Fig. 9).
(2) Start the engine and note pressure gauge read-
ing. Fuel pressure should be 338 kPa
6 14 kPa (49
psi
6 2 psi) at idle.
(3) If pressure is at O psi, connect DRB scan tool
and refer to operating instructions in the appropriate
Powertrain Diagnostics Procedures service manual.
(4) If operating pressure is above 51 psi, fuel pump
is OK but fuel pressure regulator is defective. Refer
to Fuel Pressure Regulator removal/installation.
FUEL PUMP PRESSURE TEST-5.2L ENGINES
WITHOUT PRESSURE TEST PORT
NOTE: The fuel pressure test port is used on certain
5.2L engines only. If equipped, the test port will be
located on the fuel rail near the throttle position sen-
sor. If not equipped, refer to the following procedure:
All fuel systems are equipped with a fuel tank module
mounted, fuel pressure regulator. The fuel pressure reg-
ulator is not controlled by engine vacuum.
With engine at idle speed, system fuel pressure
should be 338 kPa
6 14 kPa (49 psi 6 2 psi).
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE EVEN WITH THE ENGINE
OFF. BEFORE DISCONNECTING FUEL LINE AT
FUEL RAIL, THIS PRESSURE MUST BE RELEASED.
REFER
TO
THE
FUEL
SYSTEM
PRESSURE
RELEASE PROCEDURE.
(1) Release fuel pressure. Refer to the Fuel System
Pressure Release Procedure—Without Pressure Test Port.
(2) Disconnect latch clip and fuel line at fuel rail.
Refer to Quick-Connect Fittings for procedures. This
can be found in this section of the group.
Fig. 8 Fuel Pressure Test Port—4.0L Engine
Fig. 9 Fuel Pressure Test Port—5.2L Engine—Typical
ZJ
FUEL SYSTEM
14 - 7
DIAGNOSIS AND TESTING (Continued)