Car will not turn over

Tiny
JESSICA SCHAEFER
  • MEMBER
  • 2002 JEEP LIBERTY
  • 3.7L
  • V6
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
While driving the car just shut off and lost all power. After thirty minutes I was able to drive it home. The last two minutes every time I gave it gas it would thump in the engine area like it wasn't getting gas. I have replaced the fuel pump, crank sensor, cam shaft sensor. The fuel pump keeps losing pressure. Do you have any thoughts on this? I have no other history on vehicle. I literally had it two days when it stopped running.I should also say it still doesn't turn over at all anymore. Meaning it tries to start but can't. The engine light comes on but there are no codes. The gas light comes on after a few seconds of having it in the on position.
Saturday, June 1st, 2019 AT 4:46 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi Jessica and thanks for using 2CarPros.

The first thing I recommend is to check for fuel pressure. Since the fuel light is coming on, either you are out of gas or there is a problem at the pump (most likely wiring). Here is a link that explains how in general to check pressure. I have a feeling that if you check pressure, you'll find there is none.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the specifics for testing on this vehicle. The attached pic correlates with the directions, and the fuel pressure specifications are listed in the directions.

FUEL PUMP PRESSURE TEST
Use this test in conjunction with the Fuel Pump Capacity Test, Fuel Pressure Leak Down Test and Fuel Pump Amperage Test found elsewhere in this group.

Check Valve Operation: The bottom section of the fuel pump module contains a one-way check valve to prevent fuel flow back into the tank and to maintain fuel supply line pressure (engine warm) when pump is not operational. It is also used to keep the fuel supply line full of gasoline when pump is not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply line between the check valve and fuel injectors. Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine OFF) is a normal condition.

When the electric fuel pump is activated, fuel pressure should immediately (1-2 seconds) rise to specification.

The fuel system is equipped with a separate fuel pump module mounted, fuel pressure regulator. The fuel filter is remotely mounted. The fuel pressure regulator is not controlled by engine vacuum.

WARNING: THE FUEL SYSTEM IS UNDER CONSTANT 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.

Fig.20 Fuel Pressure Test Gauge (Typical Gauge Installation At Test Port)
pic 1
1. Remove protective cap at fuel rail test port. Connect the 0-414 kPa (0-60 psi) fuel pressure gauge (from gauge set 5069) to test port pressure fitting on fuel rail (Fig. 20). The DRB III Scan Tool along with the PEP module, the 500 psi pressure transducer, and the transducer-to-test port adapter may also be used in place of the fuel pressure gauge.
2. Start and warm engine and note pressure gauge reading. Fuel pressure should be 339 kPa + 34 kPa (49.2 psi + 5 psi) at idle.
3. If engine runs, but pressure is below 44.2 psi, check for a kinked fuel supply line somewhere between fuel rail and fuel pump module. If line is not kinked, but specifications for either the Fuel Pump Capacity, Fuel Pump Amperage or Fuel Pressure Leak Down Tests were not met, replace lower section of fuel pump module. Refer to Fuel Pump Module Removal/Installation.
4. If operating pressure is above 54.2 psi, electric fuel pump is OK, but fuel pressure regulator is defective. Replace lower section of fuel pump module. Refer to Fuel Pump Module Removal/Installation.
5. Install protective cap to fuel rail test port.

__________________________________________________

Also, check the fuel pump relay located in the power distribution box under the hood. I attached two pics to help locate it. You can simply switch it with another relay having the same part number, or here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here are a few link you may find helpful when testing.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

If these are things you have already tested, let me know. Also, let me know if you have other questions and what is found.

Take care,
joe
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Saturday, June 1st, 2019 AT 11:02 PM

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