Operation and maintenance manual

Troubleshooting Symptoms Charts QSB4.5 and QSB6.7
Page TS-36 Section TS - Troubleshooting Symptoms
Engine Speed Surges in PTO or Cruise Control
Cause Correction
STEP 1
Engine speed also surges at idle
.............
Refer to the Engine Speed Surges at Low or High
Idle symptom tree.
OK
Go To Next Step
STEP 2
Engine speed surges while in the normal operating
range and not in PTO or cruise control
.............
Refer to the Engine Speed Surges Under Load or
in Operating Range symptom tree.
OK
Go To Next Step
STEP 3
Electronic fault codes are active
.............
For instructions on how to read active fault codes,
refer to Section 1. If fault codes are active, contact
a Cummins Authorized Repair Facility.
OK
Go To Next Step
STEP 4
Moisture in the wiring harness connectors
.............
Dry the connectors with Cummins electronic
cleaner, Part Number 3824510.
OK
Go To Next Step
STEP 5
Fuel filter is plugged
.............
Measure the fuel pressure before and after the fuel
filter. Refer to Section 5.
OK
Go To Next Step
STEP 6
Fuel supply is not adequate
.............
Check the flow through the filter to locate the
source of the restriction. Refer to Section 5.
OK
Go To Next Step
STEP 7
Contact a Cummins® Authorized Repair Facility