LEMON Manuals: Even more car manuals for everyone
Home >> Jeep >> 2005 >> Wrangler Rubicon, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 488 (Powertrain Diagnostic Procedures - Gas) >> Diagnostic Information And Procedures >> Starting - Symptoms >> Symptom: *CHECKING FUEL DELIVERY >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
CHECKING FUEL DELIVERY DIAGNOSTIC TEST REFERENCE

TEST ACTION APPLICABILITY
1 Ignition on, engine not running.
With the DRBIII®, actuate the ASD Fuel System test.
NOTE: It may be necessary to use a mechanics stethoscope in the next step.

Listen for fuel pump operation at the fuel tank.
Does the Fuel Pump operate?
Yes --> Go To 2
No --> Go To 5
CAUTION: Stop All Actuations.
 All
2 Turn the ignition off.
WARNING: The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

Install a fuel pressure gauge to the fuel rail test port.
Ignition on, engine not running.
With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.
NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

Choose a conclusion that best matches your fuel pressure reading.
Below Specification
Go To 3
Within Specification
Test Complete.
Above Specification
Replace the fuel filter/fuel pressure regulator.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .
CAUTION: Stop All Actuations.
 All
3 Turn the ignition off.
WARNING: The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module.
Install special 5/16" fuel line adapter tool #6539 between disconnected fuel line and the fuel pump module.
Attach a fuel pressure test gauge to the "T" fitting on tool #6539.
Ignition on, engine not running.
With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.
NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

Is the fuel pressure within specification now?
Yes --> Repair/replace fuel supply line as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .
No --> Go To 4
CAUTION: Stop All Actuations.
 All
4 Turn the ignition off.
WARNING: The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.
Is the Fuel Inlet Strainer plugged?
Yes --> Replace the Fuel Pump Inlet Strainer.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .
No --> Replace the Fuel Pump Module.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .		 All
5 Turn the ignition off.
Disconnect the fuel pump module harness connector.
Ignition on, engine not running.
With the DRBIII®, actuate the ASD Fuel System test.
Using a 12-volt test light connected to ground, probe the (A141) Fuel Pump Relay Output circuit at the Fuel Pump Module harness connector.
Does the test light illuminate brightly?
Yes --> Go To 6
No --> Go To 8
CAUTION: Stop All Actuations.
 All
6 Turn the ignition off.
Disconnect the Fuel Pump Module harness connector.
Using a test light connected to 12-volts, probe the (Z211) Fuel Pump ground circuit at the Fuel Pump Module harness connector.
Does the test light illuminate brightly?
Yes --> Go To 7
No --> Repair the excessive resistance in the (Z211) Fuel Pump Ground circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .		 All
7 If there are no possible causes remaining, view repair.
Repair
Replace the Fuel Pump Module.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .		 All
8 Turn the ignition off.
Remove the Fuel Pump Relay from the PDC.
Using a 12-volt test light connected to ground, backprobe the (A14) Fuel Pump Relay Fused B+ circuit at the PDC.
Does the test light illuminate?
Yes --> Go To 9
No --> Repair the open or short to ground in the (A14) Fuel Pump Relay Fused B+ circuit. Inspect the fuse and repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .		 All
9 Disconnect the Fuel Pump Module harness connector.
Measure the resistance of the (A141) Fuel Pump Relay Output circuit from the relay connector to the Fuel Pump Module connector.
Is the resistance below 5.0 ohms?
Yes --> Replace the Fuel Pump Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .
No --> Repair the open in the (A141) Fuel Pump Relay Output circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 .		 All
scientia non olet · About LEMON Manuals