• Verify nature of concern.
• Verify lube oil supply pressure.
• If the nature of the concern exists hot only (hot no starts), safely bring the vehicle up to necessary temperature range. Monitor IPR (Injection Pressure Regulator) duty cycle as EOT (engine oil temperature) increases. A high- pressure oil leak should be indicated by a rising IPR duty cycle. As EOT increases and the leak rate increases, ICP pressure can begin to drop as the IPR is no longer capable of compensating.
• Check the operation of the IPR valve. Remove one of the valve covers from the engine.
Apply shop-air pressure to the high-pressure rail using special tool adapter #303-766. When the air pressure is applied, there will be a noticable air leak do to the IPR valve being in an open state.
• With the WDS, increase the duty cycle of the IPR valve. This should block that air leak. If no change is heard, the IPR valve is not functioning as commanded. Your concern could be the IPR valve or the PCM to IPR circuit. If a change in the air leak is heard, the IPR valve is operating and investigation for the high-pressure oil leak begins.
• With the IPR blocking the air leak to the oil pan, listen for the position of the air leak in the engine. A stethoscope can improve your ability to narrow down the location of the leak.
