Cummins/Onan 6CTA8.3-M (JW) Engine Engine

• No fault lamp lit.
  Cause: Possible defective ECM
  Fix: Check fuses F4 and F2 of ECM board A11. F4 (Main) - 5 Ampere F2 (Fuel solenoid or ignition) - 20 Ampere Perform restart and check for B+ voltage in at TB1-9 and voltage out at TB1-10 to fuel solenoid. If there is voltage out at TB1-10, check fuel supply solenoid, shutoff valves, etc. If there is no voltage out at TB1-10, ECM board A11 is defective. Replace.
• Low power 35
• LOP, HET, Overspeed lamp lit.
  Cause: As indicated.
  Fix: Refer to Table 4-3.
• Knock 338
• Is residual voltage across TB21-22 and -23 equal to 5 to 10 VAC or more?
  Fix: Yes: Is exciter field voltage across VR21-X and -XX at approximately 24 to 32 VDC? No: Check exciter field wiring for shorts. Replace bad wiring. Check exciter field wiring for opens. Replace bad wiring. Replace voltage regulator VR21. Check exciter field winding. Replace if bad.
• Is field breaker CB21, if equipped, at ON (fully-in) position?
  Fix: Replace defective field breaker. Remove one lead from breaker and check continuity with ohmmeter. Is breaker open? Place breaker switch to ON position. Does voltage is unstable, high or low, or causes generator AC output voltage build up? If breaker to trip, refer to other Flow Charts.
• Is engine running at correct rpm?
  Fix: No: Refer to Governor Adjustments. Yes: Are generator output connections correct and secure? No: Refer to appropriate electrical schematic. Yes: Does adjustment of Voltage Adjust control R21 (if equipped) result in correct output voltage? No: Set Voltage Adjust control R21. Check voltage adjust rheostat and replace if defective.
• Fuel or oil leaking from exhaust manifold 29
• Fault 1 or Fault 2 Over/Under Voltage or Frequency, as dedicated by customer. Restart unit and monitor gauges.
  Cause: If shutdown was due to over/under voltage, the voltage regulator may require adjustment or is faulty. Refer to Tests and Adjustments section for adjustments, replace if faulty. If shutdown was due to over/under frequency, the engine governor may require adjustment or is faulty. Refer to Tests and Adjustments section for adjustments, replace if faulty.
  Fix: Refer to Tests and Adjustments section. Restart unit and monitor gauges.
• Exhaust smoke excessive under load 80
• Excessive vibration 387
• Excessive fuel consumption 86
• Excessive engine moisture 38
• Engine will not shut off 31
• Engine starts, but stops after running short time.
  Cause: Overspeed lamp lit. Mechanical O.S. Switch or Overspeed Module (if equipped) initialized shutdown. Unstable engine operation. Low Oil Pressure lamp lit. Low oil level in engine. LOP switch faulty. High Engine Temperature lamp lit. Low coolant level in engine. HET switch is faulty. Thermostat defective. Fan belt slipping.
  Fix: Refer to Tests and Adjustments section. Perform necessary adjustments of O.S. switch or module. Perform start-up and monitor engine speed to overspeed shutdown. If shutdown occurs before desired setpoint, readjust O.S. switch/module. If adjustment does not correct fault condition, replace O.S. switch/module. Replenish as necessary. Check oil level, perform restart, and monitor oil pressure gauge. If gauge reading is within normal range, switch S1 is faulty. Replace. Replenish as necessary. Check coolant level, perform restart, and monitor engine temperature.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 6CTA8.3-M (JW).