This procedure will allow a technician to identify a pumping element or suction valve concern within the high pressure pump. This test uses an infrared temperature gun (1) to measure the external temperature of the nuts on the high pressure pump. A defective pumping element or suction valve will show a distinct temperature difference between measurements. Pumping element concerns can cause the following conditions:
- Unstable rail pressure
- Long crank times
- Codes related to rail pressure deviation
Test as follows:
- Start engine and allow engine to idle for 5 minutes.
- Using an infrared temperature gun (1), monitor the high pressure line (2, 3) nut temperatures at the high pressure pump.
- If the temperature difference between each line is within 20 degrees, go to next step.
- If temperatures difference is greater than 20 degrees, suspect a failed pumping element or suction valve. Replace pump.
- Increase engine speed to 1500 rpm and monitor the line nut temperature at the high pressure pump.
- If the temperature difference between each line is within 20 degrees, no trouble found.
- If temperatures difference is greater than 20 degrees, suspect a failed pumping element or suction valve. Replace pump.
