P0087

4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0087: Fuel Rail / System Pressure - Too Low

DTC 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.
Let the plunger moves up and down by the camshaft rotations, 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 4 to 13 MPa (40.8 to 132.6 kgf/cm2, 580 to 1,885 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 15 MPa (153 kgf/cm2, 2,175 psi), the fuel relief valve installed on gateway of the fuel delivery pipe discharges the fuel pressure and then returns the fuel back to the fuel tank.









MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM






INSPECTION PROCEDURE
HINT:
- If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- Read freeze frame data using 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.

PROCEDURE

1. CHECK FUEL LEAK (HIGH PRESSURE SIDE)
(a) Check around and beneath the car for gasoline leaks, fumes, etc.
OK:
No gasoline 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 Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the tester on.
(c) Clear DTCs.
(d) Start the engine.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(f) Read the DTCs using Techstream.
Result:





HINT: If any codes other than P0087 are output, perform troubleshooting for those DTCs first.

B -- GO TO DTC CHART
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 (CYL #1, #2, #3, #4, #5 AND #6)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the tester on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, #2, #3, #4, #5 and #6.
(d) Allow the engine to idle.
(e) Read each value of CYL #1 to #6 displayed on the tester.
(f) Check if there is a particular cylinder that the misfire count is concentrated on.
Result:






B -- REPLACE FUEL INJECTOR
A -- Continue to next step.
5. CHECK FUEL PRESSURE SENSOR
(a) Connect Techstream to the DLC3.
(b) Start the engine.
(c) Turn the tester on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
(e) Check that the fuel pressure fluctuates when the engine condition changes from idling to racing.
Result:






B -- CHECK FUEL LEAK (HIGH PRESSURE FUEL LINE)
A -- REPLACE FUEL PRESSURE SENSOR
C -- Continue to next step.
6. CHECK FUEL PUMP (FUEL PUMP OPERATION)
(a) Check the fuel pump operation Testing and Inspection.
NG -- REPLACE FUEL PUMP
OK -- Continue to next step.
7. CHECK FUEL PRESSURE (LOW PRESSURE SIDE)
(a) Check the fuel pressure (low pressure side) Testing and Inspection.
NG -- REPLACE FUEL PRESSURE REGULATOR
OK -- Continue to next step.
8. CHECK FUEL LEAK (HIGH PRESSURE FUEL LINE)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn Techstream on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
(d) Start the engine.
(e) Check that the fuel pressure fluctuations when the engine switch is turned off.
HINT: Turn the engine switch off and on (IG) before checking the fuel pressure.





Result:






A -- REPLACE FUEL PUMP FOR HIGH PRESSURE
B -- Continue to next step.
9. CHECK RELIEF VALVE
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn Techstream on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Fuel Press.
(d) Start the engine.
(e) Check the fuel pressure fluctuations when the fuel hose is pressed with your fingers.
Result:






A -- REPLACE RELIEF VALVE
B -- Continue to next step.
10. REPLACE FUEL PUMP FOR HIGH PRESSURE
(a) Replace the fuel pump for high pressure Components.
NEXT -- Continue to next step.
11. CHECK IF DTC OUTPUT REOCCURS (SEE IF DTC P0087 IS OUTPUT AGAIN)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the tester on.
(c) Clear DTCs.
(d) Start the engine.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(f) Read the DTCs using Techstream.
Result:






B -- END
A -- REPLACE ECM