Fuel - Low Pressure, Power Loss W/Tank Less Than 3/4

19-20



Engine Power Loss - Low Fuel Pressure - Fuel Pump Module Modification

MODEL:
92 MY XJS

DATE:
8/92



ISSUE:

Gradual loss of fuel pressure and engine power while driving with the fuel tank less than 3/4 filled.

During power loss, fuel rail pressure will decrease to 10 - 15 Psi.

Fuel pressure and engine power do not recover until the vehicle is allowed to sit for several hours. Then, when the vehicle is restarted, the condition may or may not re-occur.

When the fuel tank is above 3/4 filled, the condition will NOT occur.

ACTION:

^ Fill the fuel tank to FULL.

^ Use fuel pressure test adaptor JD 181 and install a fuel pressure gauge at the rail. Refer to Technical Bulletin 19-19 for the procedure.

^ Remove the vacuum hose from the fuel pressure regulator. Run the engine and observe the fuel pressure.

If the pressure is 36-38 PSI:

Modify the existing fuel pump module using the procedure detailed on the following steps.

If the pressure is less than 36 PSI:

^ Using pliers, slowly pinch the fuel return hose and observe the fuel pressure.

If the pressure increases above 38 PSI, replace the pressure regulator and then modify the existing fuel pump module using the procedure outlined on the following steps.

If the pressure does not increase, replace the fuel pump module (EBC 10123) and holder (EBC 10124). Do NOT modify the new module and holder.



To Modify the Existing Fuel Pump Module:


CAUTION:
The following procedure involves removing fuel system components and will result in the presence of fuel vapor which is extremely flammable. All necessary safety precautions must be taken.

^ Remove the module. Refer to the XJS Service Manual, repair operation number 19.45.08.

^ Completely drain the module into a waste container and wipe the module dry.

^ Remove the module from the rubber holder.

^ To prevent debris from entering the module, place a plastic bag over the top and hold in place with tape.

^ Fold the pick-up filter up from the base of the module and hold with a plastic tie strap.


NOTE:
Do not remove, cut or damage the pick-up filter. If the filter is removed or damaged, the module must be replaced.





^ Using a hacksaw blade, cut out the bottom edge of the module as indicated in Fig. 1. Be careful not to cut the pick-up filter neck. It is important that the cut is even with the bottom of the locating tabs (7/16" up from the bottom edge of the module) and extends from the short locating tab to the opposite tab, on the side of the module with the pick-up filter neck.



^ Deburr rough edges with a file and clean debris from the module. Remove the plastic bag.

^ Install the holder to the module. Secure the holder with a plastic strap.





^ Using a razor knife, trim the rubber holder to match the cut section of the module, as indicated in Fig. 2.



^ Remove the strap from the pick-up filter.





^ Turn the filter approximately 180~ on the neck so that it protrudes from under the module through the cut out section, (Fig. 3).



^ Install the module to the vehicle with a new vapor flange gasket.






PARTS INFORMATION






WARRANTY INFORMATION:

Fault Description:
Fuel Pressure Loss

Fault Code:
2GAQ