Section 5 Troubleshooting; Introduction; Theory Of Operation, Electronic Start Sequence; Initial Checks - Kohler 38RCL Manual

5.1 Introduction

Corrective action and testing in many cases requires
knowledge of electrical systems and electronic circuits.
Have an authorized distributor/dealer or trained service
technician perform testing and service.
Refer to the engine service manuals for engine service
information. See the List of Related Materials for the
document part number.
If the troubleshooting procedures in this section identify
a failed part, refer to the parts catalog for replacement
part numbers. See the List of Related Materials in the
Introduction for the parts catalog number.
5.2 Theory of Operation,
Electronic Start Sequence
The following steps trace the electronic system as wires
and components are energized and fuel, ignition, and
engine crank are added during the start sequence. Use
the steps below and refer to the wiring schematics in
section 8 to assist with troubleshooting and to check for
loose connections or damaged wires.
1. Fuel
a. When the Run button is pressed, the RDC2
controller energizes lead 70 and 71.
(1) Lead 70 energizes leads 70A, 701A, and
70B.
(2) Lead 71 supplies power to the R1 power
relay. See step 2, engine crank.
b. Lead 70A supplies power to fuel valve 1 and
fuel valve 2.
c. Lead 70B energizes the VSWITCH on the
ECM.
d. When the ECM receives the VSWITCH signal,
the ECM provides a ground to fuel valve 1, fuel
valve 2, and R1 power relay.
(1) The fuel valves open allowing fuel to flow to
the air--fuel mixer and throttle body.
2. Engine Crank
a. When the ECM provides a ground to the R1
power relay, the R1 power relay closes the R1
contact.
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Section 5 Troubleshooting

b. R1 contact energizes the starter solenoid and
provides cranking power to the engine.
3. Ignition
a. When the crank position sensor detects engine
rotation, the ECM energizes the R2 power
relay.
b. The R2 power relay closes the R2 contact.
c. The R2 contact energizes the ignition coil and
ignition module and the engine starts.
d. When the RDC2 controller senses that the
engine has reached 750 RPM, the RDC2
controller will drop power to lead 71 ending the
start sequence.

5.3 Initial Checks

Note: Read all safety precautions at the beginning of
this publication before performing any work on
the generator set.
When troubleshooting, always check for simple
problems first. Check for the following common
problems before replacing parts:
Loose connections or damaged wiring.
D
Blown fuses. See Section 5.4.2.
D
Dead battery.
D
Inadequate fuel supply.
D
primary or secondary
connections to the fuel solenoid valve, a damaged or
closed fuel shutoff valve, an empty LP fuel tank, or
other problems with the fuel supply. Check the fuel
supply pressure to the generator set.
Section 6.8, Fuel Systems.
Fault shutdown. Check for a fault message on the
D
controller display. Section 5.7 describes the warning
and shutdown fault messages. If a fault message is
displayed, identify and correct the cause of the fault
condition. Then reset the controller.
Incorrect controller settings. Always check the
D
controller settings before replacing the controller.
See Section 3.3.1 for controller settings. Refer to the
operation manual for instructions to check and
change the controller settings from the controller
Check for damaged
fuel regulators, loose
See
Section 5 Troubleshooting 59