ISBe/ISB Series Engines – Engine Speed Surges Under Load or in Operating Range

Fuel level is low in the tank

Fill the supply tank. Refer to the OEM service manual.

Electronic fault codes are active

For instructions on how to read active fault codes, refer to Diagnostic Fault Codes in Section 1. If fault codes are active, contact a Cummins Authorized Repair Facility.

Fuel supply is notadequate

Check the flow through the filter to locate the source of the restriction. Refer to a Cummins Authorized Repair Facility.

Air in the fuel system

Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary.

Vehicle parasitics are excessive

Check the vehicle brakes for dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to the OEM service manual.

Clutch is malfunctioning or is notcorrect

Compare the drivetrain specifications to Cummins recommendations. Check the clutch for correct operation. Refer to the OEM service manual.

Torque converter is malfunctioning

Check the torque converter. Refer to the OEM service manual.

Air intake system restriction is above specification

Check the air intake system for restriction. Clean or replace the air filter and inlet piping as necessary. Refer to Section 3.

Idling with excessive load

Use the PTO feature for loaded conditions at low engine speeds. Refer to the OEM service manual.

Fuel grade is notcorrect for the application, or the fuel quality is poor

Operate the engine from a tank of high-quality fuel. Refer to Section V.