Grand Cherokee 2WD L6-4.0L VIN S (1997)
Fuel Pressure Release: Service and Repair
WARNING: Because the fuel system is under constant fuel pressure, the pressure must be released before servicing any fuel system
component. This does not apply to throttle body removal.
FUEL SYSTEM RELEASE PROCEDURE
1. Loosen the fuel filler cap.
2. Remove the fuel pump relay.
3. Start and run engine until it stalls.
4. Attempt to restart the engine until it will no longer run.
5. Ensure the ignition key is off.
6. If the vehicle is equipped with a fuel pressure test port perform the following steps. For all others go to number 7 below.
NOTE: The fuel pressure test port is used on certain engines only. It equipped, the test port will be located on the fuel rail. A sealing cap is
screwed onto the test port.
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 when the pressure is released from the fuel rail. Wear proper eye protection when releasing fuel system pressure.
a. Remove the protective cap from the fuel pressure test port.
b. Use the hose and fitting, from pressure tool set 5069. Place the open end of the fuel pressure release hose, with gauge removed, into an
approved gasoline container.
c. Place a shop towel under the fuel pressure test port.
d. Connect the fitting end of the fuel hose to the fuel pressure test port.
e. After all fuel pressure is relieved, remove hose and reinstall test port cap.
7. This step is for engines without a fuel pressure test port.
a. Unplug the connector from any injector.
b. Attach jumper wires to both pins on the injector.
c. Attach the other end of one jumper wire to a good ground.
d. Touch the loose end of the remaining jumper wire to B+ for no more than 4 seconds. Repeat this twice.
8
With fuel pressure relieved the fuel system can now be opened for required work. Continue to use caution, fuel leakage is still possible.
