FREE Cummins INSITE Software: Fast Idle Warm-Up on CUMMINS Engines

Fast Idle Warm-Up

Figure 1.1 - Fast Idle Warmup (ISL8.3 CM850)

#Feature Description

This feature increases idle speed and runs the engine on 3 cylinders during extended idle periods in cold ambient conditions. When enabled, Fast Idle Warmup activates when the following conditions are met:

• The engine idles for 30 seconds
• No vehicle speed is detected
• Coolant temperature is 140 degrees Fahrenheit or colder
• Intake Manifold temperature is 15 degrees Fahrenheit or colder 

The ECM then commands the idle speed to increase to 1200 RPM and cuts out three cylinders. To maintain the fast idle speed while running on 3 cylinders, fueling for those cylinders is increased. This improves combustion efficiency and increases engine temperatures during extended idle periods in cold weather.

If the engine coolant temperature is below 32 degrees Fahrenheit, Fast Idle Warmup will activate regardless of Intake Manifold temperature. Subsequently if Coolant temperature increases above 170 degrees Fahrenheit, Fast Idle Warmup automatically deactivates. Fast Idle Warmup can also be deactivated under the following conditions:

• The vehicle is equipped with a clutch switch and the clutch is depressed
• The vehicle is equipped with a brake switch and the service brake pedal is depressed
• The accelerator is depressed

When Fast Idle Warmup deactivates, engine speed returns to the normal idle speed, and the engine idles on all 6 cylinders.

Fast Idle Warmup can be activated on vehicles equipped with manual Transmissions, when Coolant temperature is below 140 degrees Fahrenheit and Intake Manifold temperature is below 15 degrees Fahrenheit, by depressing the brake pedal and holding it in the depressed position. Fast Idle Warmup will activate after 30 seconds. Fast Idle Warmup will NOT activate by this method if any one of the following conditions are present:

• Vehicle Speed is present
• Vehicle Speed tampering faults are active
• Vehicle Speed signal faults are active
• On vehicles equipped with manual Transmissions, Fast Idle Warmup will activate if the clutch or service brake are held in a depressed position. To deactivate Fast Idle Warmup when this occurs, be sure the vehicle Transmission is in neutral, then release the clutch or service brake.
• If the vehicle is equipped with an automatic Transmission and the service brake is depressed, Fast Idle Warmup will deactivate.
• While Fast Idle Warmup is active, you can not adjust the low idle speed using the increment or decrement switch.
• If the low Idle Shutdown feature is enabled, it will shut off the engine after the low Idle Shutdown time has expired. If the low Idle Shutdown override feature is enabled, the low Idle Shutdown can be overridden just as if the Fast Idle Warmup feature were not active. Using the accelerator, clutch, or service brake to override low Idle Shutdown will not deactivate Fast Idle Warmup during the low Idle Shutdown override period.
• If the vehicle is equipped with PTO, Fast Idle Warmup will activate during PTO if the PTO speed is below 1600 RPM, the PTO load is below a set threshold, and the conditions outlined above are met. If the PTO engine speed is greater than a 1600 RPM or the load is greater than the threshold that has been set, Fast Idle Warmup will not activate. The default load percentage is set at 10%.
• If the engine ECM is responding to a J1939 engine control message from a Transmission controller, Fast Idle Warmup will deactivate.

#Adjustable Parameters

Figure 1.2 - Fast Idle Warmup (Features and Parameters)

1). Fast Idle Warmup

Select the feature name to enable or disable the feature using the dropdown list in the ECM Value column.

2). Fast Idle Warmup Idle Speed

This parameter allows minor adjustment of the Fast Idle Warmup speed and can be used to reduce vibration, such as mirror shake, depending on the application. The default speed is set at 1200 RPM.

3). Fast Idle Warmup PTO Load Threshold

The PTO load that is used to determine whether Fast Idle Warmup should activate. This parameter should be set as low as possible to insure that Fast Idle Warmup will activate to maintain engine temperatures without interfering with the PTO operating speed or load. The default value for this parameter is 10%.

#Interaction with Other Features and Parameters

→Fast Idle Warmup will not activate if PTO is activated and the load exceeds the defined threshold.

→Fast Idle Warmup will deactivate if the PTO load is under the load threshold, but exceeds the threshold during PTO operation.

→If faults are detected on either the Coolant temperature sensor circuit or the Intake Manifold temperature sensor circuit, Fast Idle Warmup uses the lowest Intake Manifold and Coolant temperatures recorded since the key switch was turned ON to determine whether Fast Idle Warmup will activate.

→If vehicle speed tampering or vehicle speed signal faults are detected, Fast Idle Warmup will not activate.

#Fast Idle Warmup Test

Use this test to manually engage the Fast Idle Warmup feature. The test functions as a simulator of the feature, enabling you to determine the most suitable engine speed when the feature is activated. Note: Fast Idle Warmup must be enabled in the Features and Parameters window before this test can be run (refer to Figure 1.1 above).

#To perform the test:

1). Attach the PC to a running engine in a non-moving vehicle.

2). Select Fast Idle Warmup Test from the list in the ECM Diagnostic Tests Wizard. Click Next, and the Fast Idle Warmup Test window opens.

Figure 1.3 - ECM Diagnostic Tests Wizard

Figure 1.4 - Fast Idle Warmup Test

3). Be sure the engine speed is 600 rpm or higher.

4). Note any messages or warnings that may be displayed.

5). Click Start.

Figure 1.5 - Fast Idle Warmup Test (Value: Inactive)

6). Instructions: To manually test Fast Idle Warmup, select Engage to begin the test. Please cycle the key switch if INSITE is closed without first stopping or canceling this test. 

Figure 1.6 - Fast Idle Warmup (Engage)

Please be patient, there is approximately 5 minutes of delay time before the engine speed begins ramping to the desired Fast Idle Warmup speed (Value: Delay).

7). Use the Fast Idle Warmup Speed spin box to adjust the idle speed up or down.

8). When the desired speed is displayed, click Adjust to send the speed to the ECM.

#Special Instructions

The Fast Idle Warmup State Monitor parameter can be used to determine whether the ECM is commanding Fast Idle Warmup:

• If the state is Inactive - Fast Idle Warmup is not active (refer to Figure 1.5 above).
• If the state is Delay - the ECM is within the 30 seconds until 5 minutes delay time before Fast Idle Warmup will become active (refer to Figure 1.6 above).
• If the state is Ramp - Fast Idle Warmup is active and the engine speed is ramping from the low idle speed to the Fast Idle Warmup speed (refer to Figure 1.7 below).
• If the state is Active - then Fast Idle Warmup is active (refer to Figure 1.8 below).

Figure 1.7 - Fast Idle Warmup (Value: Ramp)

Figure 1.8 - Fast Idle Warmup (Value: Active)

NOTE: The ECM change is temporary, lasting only as long as the test is running. To permanently change the Fast Idle Warmup speed in the ECM, use the Features and Parameters window (refer to Figure 1.2 above). The maximum amount of time that the test will run is 15 minutes, at which point the test will stop automatically. The Timer box displays the currently elapsed test time.

9) Click Disengage, then Stop to stop the test.

Figure 1.9 - Fast Idle Warmup (Disengage)

Figure 1.10 - Test stopped (Stop)

10). Click Back to perform a different test.

Read More:

Cold Idle Warm-Up on Cummins INSITE Software (CUMMINS Engines)

Intake Air Heater Control on Cummins INSITE Software (CUMMINS Engines)

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