Cummins TOP 20 THINGS THAT CAN CAUSE EXCESSIVE FUEL CONSUMPTION on a ISX CM870

Cummins

Flex

Active member
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Nov 26, 2022
Messages
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These are your top 20 things that can be causing you to spend more money on fuel.​

List of Causes & Corrections for EXCESSIVE FUEL CONSUMPTION ON A ISX CM870​




1. Operator technique is not correct

Correction​

Explain correct engine operation to the operator.

2. Equipment and environmental factors are affecting fuel consumption

Correction​

Consider ambient temperatures, wind, tire size, axle alignment, routes, and use of aerodynamic aids when evaluating fuel consumption.

3. Drivetrain is not correctly matched to the engine

Correction​

Check for correct gearing and drivetrain components. Refer to the OEM vehicle specifications.

4. Electronic fault codes active or high counts of inactive fault codes

Correction​

Read the fault codes with an electronic service tool. Refer to Section TF for fault code troubleshooting.

5. Programmable parameters or selected features are not correct

Correction​

Check the programmable parameters and the selected features with an electronic service tool. Set the parameters and features again, if necessary.

6. Turbocharger is not correct

Correction​

Check the turbocharger part number and compare it to the Control Parts List.

7. Fuel leak

Correction​

Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tanks.

8. Hubometer or odometer is miscalibrated

Correction​

Check the hubometer and odometer calibrations. Calibrate or replace the hubometer or odometer, if necessary. Calculate fuel consumption with new mileage figures.

9. Fuel grade is not correct for the application or the fuel quality is poor.

Correction​

Operate the engine from a tank of known high quality fuel.

10. Lubricating oil level is above specification

Correction​

Check the oil level. Verify the dipstick calibration and oil pan capacity. Fill the system to the specified level.

11. Engine control module (ECM) calibration is malfunctioning

Correction​

Verify that the ECM calibration is correct.

12. Vehicle speed sensor (VSS) is not correct

Correction​

Use an electronic service tool to monitor the vehicle speed while the vehicle is not moving.

13. Vehicle speed sensor (VSS) or circuit is malfunctioning

Correction​

Check the vehicle speed sensor and circuit.

14. Vehicle speed sensor (VSS) tampering has occurred

Correction​

Check the vehicle speed sensor and circuit for tampering. Check for Fault Code 242.

15. Air intake system restriction is above specification

Correction​

Replace the air filter and inlet piping as necessary.

16. Exhaust system restriction is not within specification

Correction​

Check the exhaust system for restrictions.

17. Injector is malfunctioning

Correction​

Perform the cylinder performance test. Replace injectors as necessary.

18. Engine has poor acceleration, poor response, or low power

Correction​

Refer to Section TT, Engine Performance Troubleshooting.

19. Valve lash adjustments are not correct

Correction​

Measure and adjust the valve lash setting.

20. Internal engine damage

Correction​

Analyze the oil and inspect the filters to locate an area of probable damage.
 

Frank

Member
Joined
Nov 24, 2022
Messages
13
Troubleshooting is a tedious process, so when the dealer or local mechanic tells you it might take a day or two, this is one of the reasons.
 
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