10f. High Pressure Oil Sustem Air Pressure Check
10f. High Pressure Oil System Air Pressure Check
Note: An air leak on the high pressure oil pump shafi lip seal is normal while carrying out this procedure. This is not an indication of a high pressure oil leak and the high pressure oil pump should not be replaced for this condition. If the pump is suspect carry out the High Pressure Oil Pump Test to verify the pump generates sufficient pressure to start the engine.
Note: The replacement parts may leak if all the surfaces are not oil saturated under system pressure and the seals are not correctly seated during installation.
Note: Never replace the high pressure oil pump until all high pressure oil system leaks have been repaired and the high pressure oil system is retested.
Note: A complaint of engine stalls followed by a crank no start while the engine is warm indicates a leak in the high pressure oil system. This may or may not be accompanied by DTCs P2290 or P2291. Follow this procedure to isolate the leak.
Note: If an intermittent no start condition or delayed ICP pressure rise during restart afier a 15-minute soak exists~ a small leak is suspect. Refer to the Hard Start illustration of the previous test. Remove the valve covers to inspect for leaks.
Note: Higher oil temperatures are more effective for diagnosis of high pressure oil system leaks.
Purpose:
The purpose of this test is to verify IPR valve operation and to isolate leaks in the high pressure oil system.
Recommended Procedure:
^ Verify the base engine oil pressure. Refer to Engine Inspection and Verification.
^ If the engine will start warm the engine until the EOT is greater than 80 °C (176 °F).
^ For E-series vehicles, install the Adapter, High Pressure Pump Test 303-765 or equivalent by removing the test poll plug on the top of the high pressure oil pump. For F-Super Duty vehicles, install the Adapter, High Pressure Pump Test 303-765 or equivalent by removing the ICP sensor.
Note: It is easier to find small leaks with higher pressure.
^ Pressurize the high pressure oil system up to 1379 kPa (200 psi) using a suitable tool.
^ Key ON engine OFF.
^ Using the scan too open the IPR valve by decreasing the IPR duty cycle to 0%.
^ Allow oil to drain through the IPR valve for two (2) minutes. An air leak should be heard.
^ Using the scan tool close the IPR valve by increasing the IPR duty cycle to 85%
^ Listen for an air noise change.
^ Use a stethoscope through the oil fill tube or lefi valve cover crankcase vent hole to isolate the location of the air noise change.
^ Cycle the IPR valve open (IPR duty cycle 0%) and closed (IPR duty cycle 85%) as needed to help isolate the location of the air noise. An air noise at the base of the high pressure oil pump with the IPR duty cycle at 0% is normal.
^ If no air noise change is heard the IPR valve may not be functioning as commanded. GO to Pinpoint Test R to diagnose IPR circuit DTCs. If no DTCs are present and the engine will start carry out the Injection Pressure Regulator Test in this section to verify IPR function. If the engine will not start install a new IPR valve and repeat the air pressure check. Refer to Fuel Charging and Controls Injection Pressure Regulator Valve.
^ If no air noise change is heard and the IPR valve has already been replaced carry out the High Pressure Oil Pump Test in this section.
^ If an air noise change is heard under a valve cover remove the cover(s) to isolate the location of the leak. Refer to Engine Valve Cover. Listen for leaks around the fuel injector O-Rings stand pipes and oil rail plugs.
^ If an air noise change is heard at the back of the engine a leak at the rear engine tube assembly is suspect. Refer to Engine Dissassembly and Assembly for rear engine tube assembly replacement.
^ After completing all repairs verify the high pressure oil system integrity by re-pressurizing the system and listening again for any remaining leaks while cycling the IPR valve duty cycle. Repeat the Monitor the ICP and IPR Duty Cycle While Cranking test to verify the repair.
Possible Causes:
^ Low base engine oil pressure or level
^ ICP system leak
^ Damaged discharge tube
^ Damaged rear engine tube assembly
^ Leaking high pressure tube assembly male and female fitting
^ Damaged stand-pipe or oil supply tube
^ Damaged or missing stand-pipe 0-ring
^ Damaged or missing oil supply tube 0-ring
^ Damaged or missing 0-ring between discharge tube and high pressure pump
^ Damaged or missing discharge tube 0-ring that fits inside high pressure pump cover
^ Damaged or missing high pressure pump inlet 0-ring
^ Damaged or missing 0-ring between high pressure oil rail and the injector
^ IPR failure
^ Damaged high pressure pump
Possible Leak Locations
Tools Required:
^ Scan tool
^ Stethoscope
^ Adapter High Pressure Pump Test 303-765 or equivalent