Chapter 7. Basic Troubleshooting; Preliminary Checks; Before Starting; Visual/Physical Check - Doosan G643E Service Manual

Chapter 7. BASIC TROUBLESHOOTING

Preliminary Checks

MI-07 systems are equipped with built-in fault
diagnostics. Detected system faults can be
displayed by the Malfunction Indicator Lamp (MIL)
and are covered in Chapter 9, Advanced
Diagnostics. However, items such as fuel level,
plugged fuel lines, clogged fuel filters, and
malfunctioning pressure regulators may not set a
fault code and usually can be corrected with the
basic troubleshooting steps described on the
following pages.
If engine or drivability problems are encountered
with your MI-07 system, perform the checks in this
section before referring to Advanced Diagnostics.
NOTE: Locating a problem in a propane engine is
done exactly the same as with a gasoline engine.
Consider all parts of the ignition and mechanical
systems as well as the fuel system.

Before Starting

1. Determine that the SECM and MIL light are
operating. Verify operation by keying on engine
and checking for flash of MIL light. When the
ignition key is turned on, the MIL will illuminate
and remain on until the engine is started. Once
the engine is started, the MIL lamp will go out
unless one or more fault conditions are present. If
a detected fault condition exists, the fault or faults
will be stored in the memory of the small engine
control module (SECM). Once an active fault
occurs the MIL will illuminate and remain ON.
This signals the operator that a fault has been
detected by the SECM.
2. Determine that there are no diagnostic codes
stored, or there is a diagnostic code but no MIL
light.
G643(E) Service Manual

Visual/Physical check

Several of the procedures call for a "Careful
Visual/Physical Check" which should include:
• SECM grounds for being clean and tight
• Vacuum hoses for splits, kinks, and proper
connection.
• Air leaks at throttle body mounting and intake
manifold
• Exhaust system leaks
• Ignition wires for cracking, hardness, proper
routing, and carbon tracking
• Wiring for pinches and cuts
Also check:
• Connections to determine that none are loose,
cracked, or missing
• Fuel level in vehicle is sufficient
• Fuel is not leaking
• Battery voltage is greater than 11.5 volts
• Steering, brakes, and hydraulics are in proper
condition and vehicle is safe to operate
NOTE: The Visual/Physical check is very important,
as it can often correct a problem without further
troubleshooting and save valuable time.
227 Chapter 7. Basic Troubleshooting