P0087
4GR-FSE ENGINE CONTROL: SFI SYSTEM: P0087: Fuel Rail / System Pressure - Too Low
P0087 - Fuel Rail / System Pressure - Too Low
DESCRIPTION
The high-pressure fuel system consists of the spill valve, pump plunger, check valve, relief valve and fuel pressure sensor. The spill valve opens and closes the low-pressure fuel line (from the fuel tank), the pump plunger operated by the camshaft pressurizes fuel, the check valve mechanically opens and closes the high pressure fuel line (to the fuel delivery pipe), the relief valve prevents fuel pressure from becoming extremely high, and the fuel pressure sensor located on the fuel delivery pipe monitors fuel pressure.
The high-pressure side fuel pump is installed to the cylinder head cover (bank 1) and is driven by the cam located at the rear end of the exhaust camshaft.
When the plunger moves up and down due to camshaft rotation, it produces vacuum to suck fuel and pressurizes the fuel. This fuel then pushes the check valve open and flows into the fuel delivery pipe. The ECM opens and closes the spill valve to regulate the fuel pressure to the target fuel pressure of 4 to 13 MPa (40.8 to 132.6 kgf/cm2, 580 to 1886 psi). In order to obtain and maintain the target pressure, the ECM monitors the fuel pressure using the fuel pressure sensor and performs the feedback control.
If the internal fuel pressure of the fuel delivery pipe exceeds the standard pressure of 15.3 MPa (156.0 kgf/cm2, 2219 psi), the fuel relief valve installed on the gateway of the fuel delivery pipe discharges the fuel pressure and then returns the fuel back to the fuel tank.
Text in Illustration
MONITOR DESCRIPTION
If the fuel pressure decreases even after the ECM commands the high-pressure fuel pump to close the spill control valve, a DTC is output.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG) and turn the Techstream on.
- Record the Freeze Frame Data.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) DTC Check / Clear.
- Turn the engine switch off.
- Turn the engine switch on (IG) and turn the Techstream on.
- Based on engine rpm, engine load and other freeze frame data stored in the ECM, reproduce the conditions present when the DTC was stored.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.
- Input the DTC: P0087.
- Check the DTC judgment result.
HINT
If the judgment result shows ABNORMAL, the system has a malfunction.
- If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Code / Pending.
- Read Pending DTCs.
HINT
If a pending DTC is output, the system is malfunctioning.
- If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.
HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
1. CHECK FUEL LEAK (HIGH PRESSURE SIDE)
(a) Check around and beneath the vehicle for fuel leaks, fumes, etc.
OK:
No fuel leaks present.
NG -- REPAIR OR REPLACE FUEL SYSTEM
OK -- Continue to next step.
2. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0087)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Trouble Codes.
(d) Read the DTCs.
Result:
HINT
If any DTCs other than P0087 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
3. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
(a) Has the vehicle run out of fuel in the past?
YES -- DTC CAUSED BY RUNNING OUT OF FUEL
NO -- Continue to next step.
4. CHECK MISFIRE COUNT (CYLINDER #1 (TO #6) MISFIRE COUNT)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 (to #6) Misfire Count.
(d) Allow the engine to idle.
(e) Read each value of Cylinder #1 (to #6) Misfire Count displayed on the Techstream.
(f) Check if there is a particular cylinder that the misfire count is concentrated on.
Result:
B -- REPLACE FUEL INJECTOR Removal
A -- Continue to next step.
5. CHECK FUEL PRESSURE SENSOR
(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(e) Check that the fuel pressure fluctuates when the engine condition changes from idling to racing.
Result:
C -- CHECK FUEL LEAK (HIGH PRESSURE FUEL LINE)
B -- REPLACE FUEL PRESSURE SENSOR
A -- Continue to next step.
6. CHECK FUEL PUMP (FUEL PUMP OPERATION)
(a) Check the fuel pump operation Testing and Inspection.
NG -- GO TO FUEL PUMP CONTROL CIRCUIT
OK -- Continue to next step.
7. CHECK FUEL PRESSURE (LOW PRESSURE SIDE)
(a) Check the fuel pressure (low pressure side) Testing and Inspection.
NG -- REPAIR OR REPLACE FUEL PRESSURE REGULATOR (FUEL PRESSURE REGULATOR, PIPE LINE AND FILTER)
OK -- Continue to next step.
8. CHECK FUEL LEAK (HIGH PRESSURE FUEL LINE)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(d) Start the engine.
(e) Check if the fuel pressure fluctuates when the engine switch is turned off.
HINT
Turn the engine switch off and on (IG) before checking the fuel pressure.
Result:
B -- REPLACE INJECTOR DRIVER
A -- Continue to next step.
9. CHECK FUEL RELIEF VALVE
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(d) Start the engine.
(e) Check if the fuel pressure fluctuates when the fuel hose is pressed with your fingers.
Result:
B -- REPLACE FUEL RELIEF VALVE
A -- Continue to next step.
10. REPLACE INJECTOR DRIVER
(a) Replace the injector driver Removal.
NEXT -- Continue to next step.
11. CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0087 IS OUTPUT AGAIN)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear the DTCs.
(d) Start the engine.
(e) Enter the following menus: Powertrain / Engine / Trouble Codes.
(f) Read the DTCs.
Result:
B -- END
A -- Continue to next step.
12. REPLACE FUEL PUMP FOR HIGH PRESSURE
(a) Replace the fuel pump for high pressure Testing and Inspection.
NEXT -- Continue to next step.
13. CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0087 IS OUTPUT AGAIN)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear the DTCs.
(d) Start the engine.
(e) Enter the following menus: Powertrain / Engine / Trouble Codes.
(f) Read the DTCs.
Result:
B -- END
A -- REPLACE ECM Removal