Cold Mode on Status Flags Caterpillar ET Software

Cold Mode

Figure 1.1 - Cold Mode and No Engine Speed (Status Flags)

The ECM limits engine power during cold mode operation and the ECM modifies injection timing during cold mode operation. Cold mode operation provides the following benefits:
  • Increased cold weather starting capability
  • Reduced warm-up time
  • Reduced white smoke
The Electronic Control Module (ECM) limits engine power during cold mode operation. The ECM may modify the injection timing and the ECM may cut out certain engine cylinders. This will increase startability and this will reduce warm up time. Cold mode is activated whenever the engine coolant temperature falls below a predetermined value. Cold mode remains active until the engine has warmed or a time limit is exceeded.

#Cold Mode Operation
The ECM will set the cold start strategy when the coolant temperature is below 63 °C (145 °F).

When the cold start strategy is activated, low idle rpm will be increased to 1000 rpm and engine power will be limited.

Cold mode operation will be deactivated when any of the following conditions have been met:
  • Coolant temperature rises above 70 °C (158 °F).
  • The engine has been running for 14 minutes.
Cold mode operation varies the fuel injection amount for white smoke cleanup. Cold mode operation also varies the timing for white smoke cleanup. The engine operating temperature is reached before the walk-around inspection is completed. The engine will idle at the programmed low idle rpm in order to be put in gear.

After the cold mode is completed, the engine should be operated at low rpm until normal operating temperature is reached. The engine will reach normal operating temperature faster when the engine is operated at low rpm and low-power demand.

#Cold Cylinder Cutout
The engine uses a strategy for the cold cylinder cutout to reduce white exhaust smoke after start-up and during extended idling in cold weather.

During a cold start and/or extended periods at low idle, the engine's Electronic Control Module (ECM) turns off one unit injector at a time to determine if each cylinder is firing by monitoring the change in the fuel rack. If a cylinder is firing, the ECM turns on the injector. If a cylinder is not firing, the injector is turned off. This cold cylinder cutout provides the following benefits: reduction of white smoke, improved engine starting, reduction in the use of ether injection and reduction of warmup time.

NOTE: During operation of the cold cylinder cutout, the engine may seem to misfire. This is normal. No corrective measures are necessary.

The cold cylinder cutout is activated after all the following conditions are met:
• The cold cylinder cutout is programmed to ENABLED.
Figure 1.2 - Cold Cylinder Cutout (Enabled)
• The engine speed is equal to high idle or below high idle.
• The fuel rack is less than 13 mm (0.50 inch).
• The jacket water coolant temperature is below 63 °C (145 °F).

The cold cylinder cutout strategy is activated 10 seconds after the engine starts and the engine reaches idle speed or 3 seconds after ether injection is completed.

The cold cylinder cutout is deactivated if any of the following conditions are met:
• The cold cylinder cutout is disabled with the Cat® Electronic Technician (ET).
• The jacket water coolant temperature rises above 70 °C (158 °F).
• The cylinder cutout test is activated.
• The ether injection is used.
• The coolant temperature sensor has failed.

If the fuel rack is greater than 13 mm (0.50 inch), the cold cylinder cutout deactivates for 3 seconds. The cold cylinder cutout will deactivate for 3 seconds when the engine speed varies by more than ± 50 rpm as the cold cylinder cutout begins. A new engine speed is established when the cold cylinder cutout reactivates.

The cold cylinder cutout deactivates for 30 seconds when the engine speed is at low idle for 10 seconds and the engine speed falls by more than 50 rpm below low idle.

No Engine Speed
It's normal to see the "No Engine Speed" on Status Flags while power switched ON or Engine Cranking. It will not go away until the Engine Starts, even when you are seeing Engine Speed in Status Tool on CAT ET Software.



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