Engine Operation Procedures
Important: For cold-weather starting, engine break-in, and cold-weather operation, refer to the engine manufacturer’s manual for detailed instructions.
Operating vehicles in areas where there are concentrated flammable vapors (such as diesel, gasoline, or propane fumes) can create a hazardous situation. These vapors can be drawn into the engine through the air intake, and cause engine overspeed. Be especially cautious of low-lying or closed-in areas, and always check for signs that flammable vapors may be present.
Danger: Do not operate the engine in an area where flammable vapors such as gasoline or diesel fumes are present. Shut down the engine when in an area where flammable liquids or gases are being handled. Failure to observe these precautions could result in serious injury or death.
All diesel engines have been built to comply with the requirements of the Federal (U.S.) Clean Air Act. Once an engine is placed in service, the responsibility for meeting both state and local regulations is with the owner/operator. Good operating practices, regular maintenance, and correct adjustments are factors that will help to stay within the regulations.
Adequate maintenance of the engine, which is the responsibility of the owner/operator, is essential to keep the emission levels low.
The driver should be familiar with the vehicle warning system in order to bring the vehicle to a safe stop if the engine malfunctions. If the driver doesn't understand how the warning system works, an engine shutdown could occur, causing a safety hazard. See General Description for information on the control panel for the engine.
Follow the directions in the Cummins engine manufacturer's operator's manual and in this manual for trouble-free, economical vehicle engine operation.
Notice: Stop the engine at the first sign of malfunction. Almost all malfunctions give some warning to the operator before significant damage occurs. Many engines are saved because alert operators heed the warning signs (sudden drop in oil pressure, unusual noises, etc.) and immediately shut down the engine.
- Cummins diesel engines are designed to operate successfully at full throttle under transient conditions down to rated rpm. This is consistent with recommended operating practices.
- Depending on the vehicle gearing, the posted speed limit can sometimes allow operation in either of the top two gears; however, for improved operating efficiency (fuel economy and engine life), operate in the top gear at reduced rpm rather than in the next lower gear at the maximum rpm.
- Cruise at partial throttle whenever road conditions and speed requirements permit. This driving technique permits operating within the most economical power range of the engine.
- When approaching a hill, open the throttle smoothly to start the upgrade at full power, then shift down as desired to maintain the optimum vehicle speed. The high torque of the engine may permit topping some grades without shifting.
- Engines are designed to operate over a wide speed range. More frequent shifting than necessary does not allow proper utilization of this flexibility. The driver who stays in top gear and uses the wider speed range will achieve the best fuel economy.
- The Cummins engine is effective as a brake on downhill grades, but take care not to overspeed the engine going downhill. The governor has no control over engine speed when the engine is being pushed by the loaded vehicle.
- Never turn the ignition switch to the OFF position while going downhill. With the engine still in gear, fuel pressure will build up against the shutdown valve and can prevent it from opening when the ignition switch is turned to the ON/RUN position.
- Use a combination of brakes and gears to keep the vehicle under control at all times, and to keep the engine speed below the rated governed rpm.
- Check the coolant temperature and oil pressure gauges frequently.
- Do not idle the engine for more than 10 minutes. Long periods at low idle can damage the engine.
- If the engine starts to overheat, reduce the power output of the engine. Do one, or both, of the following: (1) Release pressure on the accelerator pedal; (2) Shift to a lower gear. If the temperature does not return to normal, shut down the engine.
Notice: Do not allow the engine to exceed its governed speed, or serious engine damage could result.
Notice: Continuous operation below 140°F (60°C), above 212°F (100°C), or with the oil pressure below 10 psi (69 kPa), can damage the engine.
Note: Long periods of idling are not good for an engine because the combustion chamber temperatures drop so low that the fuel may not burn completely. This will cause carbon to clog the injector spray holes and piston rings, and can result in stuck valves.