Cummins - TECHNICAL TIPS

The following lists all common Technical Tips for Cummins Engines and DPF/SCR Systems.

For Pre-2010 engines, discard all maintenance items relating to the SCR System (I.E. SCR and DEF items).

For best diagnostic results use Cummins INSITE software with NEXIQ2 adapter.

TECHNICAL
INFORMATION

Engine Oil Level - Look not just for Low Level, but HIGH LEVEL. Fuel Dillution from failing Fuel Injectors, Cylinder Washout, Etc, can cause High Oil Levels (in addition to Coolant Entry).
Fuel and Oil Consumption - Check with Operator to determine if there has been recent increases in Fuel or Oil Consumption, or other changes in engine performance. Engine issues such as low power, or frequent DPF REGENs required, could indicate a fueling problem. With use of Cummins INSITE or Scan Tool, the High Pressure Fuel Rail Pressure (Command) vs (Actual) can be tested under loaded engine conditions to determine if Fuel Injectors, Fuel Pump, or other HPCR Fueling Components are failing.

Diesel Fuel and DEF Fluid - Smell the Fluids to ensure correct. Contamination in fluids is a major problem in diesel applications.
Oil Leaks - Look closely for any Oil Leaks on the engine. Oil Entry into the CAC and Intake is a very common problem due to lack of Crankcase Breather Element replacements. This causes Soot/Oil to mix in the EGR System and cause major engine problems. In severe cases, the CC Pressure may be so high that oil will spray out of the dipstick tube, when the dipstick is removed.

Heat Damage to DPF/SCR WIRING HARNESS - Over time, electrical wiring near the exhaust system can fall down onto the hot surfaces, and become damaged. Detailed diagnostic work can be required to find the source of electrical short/open circuits.

DPF REGEN Full Test - Running a DPF Parked REGEN can provide significant info on the DPF (and Engine) Performance. Look at Exhaust Temps over duration of REGEN and compare to proper running REGEN. Within the first 5 minutes of the REGEN the Turbocharger VGT Actuator will close (85-99%) and Exhaust Temps will exceed 500F. Next the DPF Fuel Injector will turn on, within the next 5-10 minutes, the DOC Outlet Temperature should exceed 1,000F.

SCR PERFORMANCE Test - Running an SCR Performance Test is the most efficient way to test the SCR System. There are (4) stages of the test, that ensure all major components are working well. The final stage, stage #4, is the most important, as this stage confirms the SCR System is running more than 90% efficient. Efficiency is measured by comparing the Outlet NOx Sensor to the Inlet NOx Sensor, to confirm the SCR System is reducing NOx emissions by over 90%.