1999 jeep c. 4.0 litre engine. Fuel drips from muffler wont start

Check the exhaust sys and make sure the muffler or converter is not plugged. If so it puts back pressure on the engine and will not allow fuel in to start. Hope this helps.

The computer might have to be reset.Check you manual to see if you can reset it or try disconnecting the battery.

The first thing i would check is the fuel system hook a fuel pressure gauge up to the fuel rail and check the fuel pressure, after you have verified the fuel pressure is good let the gauge sit and monitor how much "bleed down" occurs if the bleed down is out of spec i would bet the fuel pressure regulator is bad or theres a leaking fuel injector causing fuel to drip into 1 or more of the cylinders causing a rich condition at startup.

For 2000 Jeep Grand Cherokee the Fuel Filter is located under vehicle, driver side, below bed area, front of fuel tank, mounted on chassis in fuel line.



Fig. Fuel filter/pressure regulator location-1999-01 models







Fig. Fuel filter/pressure regulator-Grand Cherokee

1. Before servicing the vehicle, please familiarize yourself with safety procedures.
2. Relieve the fuel system pressure.
3. Remove or disconnect the following:
   Negative battery cable Fuel supply, return and pressure lines Mounting bolts Fuel filter/pressure regulator

To install:

1. Install or connect the following:
   Fuel filter/pressure regulator to the body. Torque the bolts to 30 inch lbs. (3 Nm). Fuel pressure, return and supply lines Negative battery cable
2. Start the vehicle, check for leaks and repair if necessary.

Gooe luck (remember rated this post).

Keep in mind that you have several components there:
- Fuel Pump Sender Assembly,
- Fuel Pressure Regulator,
- Fuel Rail Assembly, and
- Fuel Injectors.

1.- Fuel Pump (Sender Assembly) - TESTING
Refer to the accompanying charts for fuel pump diagnosis and testing.

The fuel injection system remains under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.



Fig. 3.1L engine OBD system check to be done before fuel pump relay circuit diagnosis




Fig. 3.1L engine fuel pump relay circuit diagnosis (1 of 2)




Fig. 3.1L engine fuel pump relay circuit diagnosis (2 of 2)




Fig. View of the fuel pressure test port (Schrader valve)-3.1L engine

A - 3.1L engine fuel system pressure test (1 of 4)
B - 3.1L engine fuel system pressure test (2 of 4)
C - 3.1L engine fuel system pressure test (3 of 4)
D - 3.1L engine fuel system pressure test (4 of 4)



Fig. The fuel pump/fuel sender module assembly is mounted in the fuel tank


2.- Fuel Pressure Regulator - REMOVAL & INSTALLATION

(the fuel pressure regulator, which is located on the fuel rail assembly)

NOTE: Before removing the fuel regulator assembly, place a clean shop towel under the regulator to catch any fuel drips

1. Properly relieve the fuel system pressure.
2. If not done already, disconnect the negative battery cable.
3. On the 3.1L engine, remove the intake manifold plenum, as outlined in .
4. On the 2.4L engine, remove the fuel rail. Refer to procedure earlier in this section.
5. Detach the vacuum line from the regulator.
6. Place a shop towel under the regulator to catch any fuel that may drip out. Unfasten the fuel pressure regulator retaining screw, then remove the regulator by twisting and pulling it from the fuel rail.
7. Remove and discard the O-ring seal. Inspect the filter screen for contamination and replace if necessary.
   

To install:

1. Prior to assembling the pressure regulator to the fuel rail, lubricate the new rail-to-regulator O-ring seal with clean engine oil.
2. Place the O-ring on the pressure regulator and install the pressure regulator to the fuel rail.
3. Install the retainer or coat the regulator mounting screws with an approved thread locking compound and secure the pressure regulator in place. Tighten the mounting screw to 76 inch lbs. (8.5 Nm).
4. If removed, install the fuel rail assembly to the engine.

WARNING The fuel return pipe must be connected before tightening the regulator retaining screw to prevent the regulator from rotating. Rotation of the regulator could damage the retainer and spacer bracket and lead to a fuel leak at the regulator inlet.

1. Connect the fuel feed line and return line to the fuel rail assembly, use a backup wrench on the fittings to prevent turning.
2. Attach the vacuum line to the regulator.
3. On the 3.1L engine, install the intake manifold plenum.
4. Connect the negative battery cable. Turn the ignition to the ON position for two seconds, then turn it to the OFF position for ten seconds. Turn again to the ON position and check for fuel leaks.

continue...

i would check the pcv valve and fuel filter.

Have you tried to switch your car on, wait 3 sec's and then start the engine? reason: If the pressure in the fuel system went down very fast, it need some sec's to arrive the pressure it needs to start. Also possible: switch on, wait 2 sec's, switch off, on and start. This does the same I told above. If that works, change the fuel pump or let this item checked be a specialist (it's expensiv to replace it).

does it have a vacuum controlled fuel pressure regulator, if so check it for leaks into the intake. Also check fuel pressure

Sound like fuel pump. Need to check fuel pressure. It seem to be finally getting back up to the motor, then starting up. Try parking the front of the car down hill and see if it starts up a few days in a row????

CHECK INJECTOR LEAK DOWN. INSTALL FUEL PRESSURE GAUGE, PRESSURIZE FUEL SYSTEM BY LETTING ENGINE RUN FOR A MINUTE, SHUT ENGINE DOWN, AND OBSERVE FUEL PRESSURE. IT SHOULD NOT DROP BY MORE THAN 15-20 PSI IN A HALF HOUR. IF IT DOES PRESSURIZE FUEL RAIL AGAIN AND REMOVE FUEL RAIL WITH INJECTORS STILL ATTACHED AND LOOK FOR FUEL DRIPPING OUT OF INJECTORS. IF FUEL IS DRIPPING REPLACE INJECTORS AND SEALS.