Nov 072017
 

Jeep Grand Cherokee

Jeep will only start on second crank. Driving for 10 minutes and seems like it loses power, rpm drop , catch again, when I get it going it hobbles along and will not exceed 20mph or above 1500 rpm. Had vacuum serviced but problem came back??.


My first thought is fuel pressure regulator. The regulator acts as a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine. A second check valve is located at the outlet end of the electric fuel pump. This is assuming the check engine light is not on.

Fuel Pressure Regulator/Fuel Filter

A combination fuel filter and fuel pressure regulator is used on all engines. It is located on the top of fuel pump module.

fuel pressure regulator location diagram 1998 Jeep Grand Cherokee

Fuel Pressure Regulator Operation:

The pressure regulator is a mechanical device that is not controlled by engine vacuum or the Powertrain Control Module (PCM)

The regulator is calibrated to maintain fuel system operating pressure of approximately 339 kPa ± 34 kPa (49.2 psi ± 5 psi) at the fuel injectors. It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter is also part of the assembly.

Fuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator.

fuel pressure regulator 1998 Jeep Grand Cherokee

 

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