Series 50 – Section 24.4 High Fuel Oil Temperature Return

Section 24.4
High Fuel Oil Temperature Return

To determine if high fuel oil temperature return is causing rough running or stalling, perform the following: ‪

1. Install the Diagnostic Data Reader to the vehicles Display Data Line Adaptor, see Figure "Typical Display Data Line Adaptor" ; refer to OEM guidelines.
   

   Figure 1. Typical Display Data Line Adaptor

2. Start and run the engine.
3. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range, 88-96°C (190-210°F).
   1. If the return fuel oil temperature is less than or equal to 60°C (140°F), refer to "24.5 Improper Injector Calibration Setting (DDEC III Engines Only)" .
   2. If the return fuel oil temperature is greater than 60°C (140°F), resolve the high fuel oil temperature; refer to "24.4.1 High Fuel Oil Temperature Resolution" .

Section 24.4.1
High Fuel Oil Temperature Resolution

Perform the following steps to resolve high fuel oil temperature: ‪

1. Remove and replace fuel oil filter(s); refer to "2.7 Fuel Filters (Spin-On)" .
2. Inspect check valve for any restricted fitting; refer to "2.8.2 Fuel Return System Check Valve" .
3. Replace both the restrictive fitting or check valve; refer to "2.8.4 Installation of PRO-CHEK ® Fuel System Check Valve" .
4. Verify fuel oil filter(s) replacement; refer to "24.4.1.1 Test the Engine with Replaced Oil Filters" .

Section 24.4.1.1
Test the Engine with Replaced Oil Filters

Perform the following steps to determine if the replaced oil filter(s) resolved the rough running or stalling condition:‪

1. Start and run the engine.
2. Run the engine through its operating range with no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range, 88-96°C (190-210°F).
   1. If the engine is not running rough or stalling, no further troubleshooting is required. Shut the engine down.
   2. If the engine is running rough or stalling, shut the engine down. Check for improper injector calibration setting; refer to "24.5 Improper Injector Calibration Setting (DDEC III Engines Only)" .