20/40REOZJB Troubleshooting Guide

Newer DecisionMaker Info

  • Connect to controller with sitetech
  • Cable is USB A to Firewire

How to program Woodward DPG

  • Make RJ11 to RS232 adapter
  • Power controller using 12v and ground or 5v through RJ11 Port
  • Use universal PST to pull config

Throttle stops

  • Set minimum throttle stop to 60hz no load cold
  • Max throttle stop is zset to prevent technicians from revving generator by hand.

Force engine to run without controller

  • Jump 12v to woodward actuator
  • Start engine
  • When actuator loses 12v, return spring pulls actuator to off position internal to injection pump

Disable starting circuit

  • Unhook trigger wire from solenoid under voltage regulator

Governor Info

  • The woodward speed controller does not communicate with the decision maker. It is standalone and it keeps the engine running provided there is a good MPU signal, power and ground.
  • The woodward actuator has a return spring that turns the engine off when power is lost
  • You can program the governor with universal PST
  • Controller uses standard RS232 communication, you just need to make an adapter for it.

Generator not detecting RPM?

  • There is a crank sensor on the alternator end. It is how the decision maker detects the engine is running. The speed governor does not communicate with the decisionmaker.

AUX Fault - Generator Won’t Run

  • Coolant Temperature Switch Issue:
    Coolant temperature switch tends to short out on the thermostat housing. Ensure it’s not shorted and that the radiator is full of coolant.
    (Do not bypass the temperature sensor! This can be critical in cold weather.)
    Source

  • If AUX fault persists (solid):
    The control board likely needs to be rebuilt or replaced.

AUX Fault - Generator Will Run

  • Jump or bypass the coolant level sensor to rule it out
  • Ensure the safeguard breaker is set to ON.
  • Check if AC voltage is sufficient. If not:
    Replace the voltage regulator or diode kit (split activator kit) located at the end of the alternator. —

AUX Fault Light Acting Funky?

  • Inspect the battery terminal connections.

No Power Past Run Relay?

  • Check the glass fuse on the main board to ensure it’s not blown.

Overspeed Warning

  • Check the sensor near the flywheel at the middle for dirt and correct spacing.
  • Check the Woodward speed regulator below the control board on the side of the cover.
  • Crank Sensor Part Number: Magnetic Pickup (255750)
  • Make sure throttle is moving freely on Standanyne pump

Generator running choppy?

  • Make sure fuel system isn’t leaking or sucking air
  • Clean crank sensor and adjust while the engine is running. (You need 2 wrenches!)
  • Adjust governor speed after generator is running correctly.

Diode on starter solenoid

  • Diode is to prevent starter hanging. Do NOT bypass any diodes!

Voltage and HZ too low

  • Inspect voltage sensing wires and fuses for voltage sensing wires, a phase could have a fuse blown or wiring compromised.

Generator Coolant Low, but No Visible Leak?

  • Add an overflow tank and replace the radiator cap.

Intermittent Alarms

  • Check the coolant heater’s performance and the coolant tank level.
    Cold coolant or fluctuating fuel tank levels (low at night/high during the day) could trigger alarms.

Set to Run but Won’t Start

  • Flip the switch a couple of times; the issue might be a bad switch or failing control board. (Full solution unavailable.)

  • Make sure no alarms are on other than switch not in auto.

Voltage Low

  • Adjust the voltage potentiometer.
    Ohms range for potentiometer: (XXX-XXX).
    • If potentiometer checks out and the generator doesn’t show 500-600V on any setting, the voltage regulator (72-360800-00) is likely bad.
      Minimum Voltage for No AUX Fault: 350V.

Control Board Information

  • Name: DEC3+ Logic Board.
  • Pinout: Currently unavailable.
  • Run relay and start relay require two fuses.
  • Input power originates from one of the pins closer to the edge of the red connector.

Running the Engine Without a Controller

  1. Send 12 volts to the fuel shut-off solenoid.
  2. Jump the starter solenoid.
  3. (Optional) Throttle actuator may need bypassing.

Overcrank Issues

Possible causes include:

  • Poor fuel quality.
  • Clogged fuel filter.
  • Exerciser not set.
  • Block heater not working.
  • Weak battery.
  • Weak starter.
  • Shorted coolant temperature sensor.
    (Applicable to all brands of generators.)

Testing the Woodward Actuator

  • The actuator has three pins at the top.
    It receives ___ volts, with polarity changing direction depending on actuator movement.
  • To test:
    • Use a power probe to manually move the actuator.
    • Alternatively, remove the actuator and verify its function manually.

Dropped an Item Under the Generator Head?

  • Remove the 4-bolt panel on the side of the generator to access and retrieve the item.

Low Fuel Sensor

  • Low fuel sensor is normally open, when fuel is full. Pin 63 from low fuel sensor. Relay K8 on Common fault relay kit

Low Coolant Sensor

  • Low coolant sensor is normally _____, when coolant is full. The sensor eithers grounds pin 31a out or opens the circuit

Alarms not working correctly?

  • Verify functions of alarms inside relay kit. Check continuity of relays and try to use 12v or ground to cycle them.

Commonly used wiring method of alarms?

  • Common failure relay on right side of alternator back panel.

Voltage above or below 60hz?

  • Adjust the speed governor for the Stanadyne pump to run at 1800rpm. (Woodward or equivalent)

Wires below injection pump

  • They are for the fuel advance solenoid. (Stanadyne 33240)
  • Ties in with coolant temperature switch

Fuses

  • Fuse F1 - Remote Annunciator
  • Fuse F2 - 3 amp controller fuse
  • Fuse F3 - Engine/Accessories