Doosan D20S-7 - Page 100

Operation Section
-97-
Symptoms
Impossible
to start
Poor starting
Poor idle Poor driving control Engine stall Other
Check that symptoms are detected with self-diagnosis.
Check that symptoms are in fall-safe condition.
Sensor malfunction
⊕: Highly possible
◆: Possible
No initial combustion
Initial combustion
When en
g
ine is cold
When en
g
ine is warmin
g
up
Fast idle is not effective
High idle rpm
Low idle rpm
Inconsistent idle when engine is cold.
Inconsistent idle when warming up
Poor power output
Poor acceleration
Engine rpm does not increase smoothly.
During surge and acceleration
During surge and constant speed driving
Knocking
Backfire
After-burn
At Idle
Driving
During deceleration
During a heavy load
Engine over temperature (Overheat)
Poor fuel consumption efficiency
Description/notable
characteristics
of the symptom
Sensor
ground
(coolant
temperatur
e sensor,
throttle
position
sensor)
OPEN/
SHORT
◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆◆ ◆
• The same as the open circuit
in the applicable sensor.
Control unit
and
connector
Poor
connectio
n water
entry?
◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆
• A slightly raised connector
often results in poor
connection. Entry of water
causes engine stall, and
afterwards it is momentarily
impossible to restart engine.
In some cases, restarting is
possible after a short wait.
LPG fuel
pressure
sensor
OPEN/
SHORT
◆◆
Fuel
changing
switch
OPEN ⊕
• Fuel changing cannot be
done.
LPG fuel
pressure
sensor
OPEN ⊕ ⊕ ⊕ ⊕ ⊕ ◆ ◆ • LPG interception valve OFF.