How to Troubleshoot Cummins Engine Problems

Cummins engines have had problems, especially the 1999, 2000 and 2001 models. In these years, the Cummins 5.9-liter engine was prone to cracks in the side block. According to Lock-N-Stitch, Inc. there was no recall of the engine. Cracks in the engine caused by thermal expansion stress decreased the flow of coolant. Essentially, the design of the engine restricted the flow of coolant to the cylinders, cylinder head, and lower walls and outer walls of the engine block. Engage in a routine troubleshooting schedule if you own a vehicle with a Cummins engine.

Procedures:
1. Look for white smoke coming from the tail pipe. White smoke indicates that the coolant and the oil have mixed in the engine.
2. Check the color and consistency of the oil in the Cummins engine. If the oil is thick, milky and light brown in color, then the engine is blown.
3. Listen to the sound of the engine as it fires up. Oil fouled spark plugs can cause a misfire sound. Worn pistons cause a rapid ticking sound.
4. Tune up the engine if it is smoking and running rough, but run a cylinder balance test beforehand. If the cylinders are not running correctly, a tune up won't help the problem. A cylinder balance test determines if the cylinders in the engine are producing equal amounts of power. Use an engine analyzer, attach the cables to the spark plug, push the button on the analyzer and the spark plug will short out. Print out the engine speed reading. If the engine speed changes, there is an issue with the cylinder. This test also will determine which cylinders have bad valves and compression rings.
5. Conduct an engine misfire test. Misfire codes are in the P0300 range. Random misfire is a PO300 code. This test determines if an individual cylinder is not firing. A P0301 code is a misfire of cylinder 1 and a P0308 is a misfire in cylinder 8. The engine analyzer is a handheld device that attaches to the diagnostic harness of the vehicle's computerized system. The vehicle will run rough, lack acceleration power and get poor gas mileage.
6. Attach the engine analyzer to the diagnostic harness of the vehicle's computerized system to determine if there is a secondary ignition failure. From the secondary ignition pattern print-out, you can read where the vehicle is having air/fuel issues and mechanical faults. If it indicates a problem, you may need to replace the ignition coil, spark plugs and wires, distributor cap and/or rotor. Get a secondary ignition pattern from the dealership showing how the engine needs to fire. Compare your reading to that of a normal secondary ignition pattern to determine if the engine is firing correctly at the point of turning the engine over.