The Detroit Diesel Series 60 engine utilizes oil temperature data for critical functions like engine fan operation, protection derates/shutdowns, and even fuel and timing adjustments, especially during cranking and idle. Understanding the role of the oil temperature sensor and its impact on engine performance is crucial for Series 60 owners and technicians. This article will discuss the importance of the oil temperature sensor and its impact on cold start functions in a Detroit Diesel Series 60.
The Importance of Oil Temperature for Cold Starts
The Detroit Diesel Electronic Control (DDEC) system heavily relies on oil temperature readings to manage cold start functions. Unlike some engine manufacturers, Detroit Diesel utilizes oil temperature to modify fueling and timing significantly. For instance, at cranking speeds (around 200 RPM), the DDEC can advance timing by up to 3 degrees and nearly double the fuel delivery if the oil temperature is below -30 degrees Fahrenheit compared to 200 degrees Fahrenheit. This extra fuel is necessary to overcome the increased viscosity of cold oil and achieve a stable idle speed.
Common Issues with the Oil Temperature Sensor
A faulty or unplugged oil temperature sensor can lead to various problems. While some might consider disconnecting the sensor to avoid derates or shutdowns, this can have negative consequences for a Detroit Diesel engine. An unplugged sensor can trick the DDEC into thinking the oil is extremely cold, resulting in excessive fuel delivery and timing advance, even when the engine is warm. This can lead to poor fuel economy, increased emissions, and potential engine damage.
A common symptom of a malfunctioning oil temperature sensor on a DDEC IV Series 60 is a persistently high idle speed (900 RPM) even after the engine has warmed up. This is because the DDEC maintains a higher minimum idle below 60 degrees Fahrenheit oil temperature. On DDEC III systems (pre-October 1997), diagnosing a bad oil temperature sensor requires using a datalink device to read the sensor’s output.
Proper Cold Start Procedure
Instead of tampering with the oil temperature sensor, the correct cold start procedure for a Detroit Diesel Series 60 involves a simple throttle activation sequence. By turning the ignition on, fully depressing and releasing the accelerator pedal twice, and then holding it down while cranking, the DDEC provides the necessary fuel enrichment for a cold start without the risks associated with a disconnected or faulty sensor.
Conclusion
The oil temperature sensor plays a vital role in the performance and operation of a Detroit Diesel Series 60 engine. Understanding its function and potential issues is crucial for proper maintenance and troubleshooting. Utilizing the correct cold start procedure and addressing any oil temperature sensor problems promptly will ensure optimal engine performance, fuel efficiency, and longevity. Contact a qualified diesel technician for assistance with diagnosing and repairing any issues related to the oil temperature sensor. While the exact location of the sensor can vary slightly depending on the specific Series 60 configuration, consulting the engine’s service manual is recommended for precise location information. Diesel Control Service, a company specializing in Detroit Diesel engines, can provide expert assistance. You can reach them at 412-327-9400 or visit their website at www.dieselcontrolservice.com.
