Page 1003 - Workshop Manual - Tunland (2017)

DIAGNOSTICS - ENGINE CONTROL SYSTEM 04-317

BAD ACCELERATION, POOR PERFORMANCE 04

Fault phenomenon Diagnosis logic Possible reasons
• Injector fault
• Leakage in the intake
system
• Low fuel pressure
• Injector • Air filter blocked
• Intake system • Electronic throttle fault
• Fuel system • Block in fuel filter
Bad acceleration, poor • Injection timing • Incorrect injection timing
performance
• Electronic throttle valve • Air fuel ratio control system
• Exhaust system fault
• ECM • Fuel supply system fault
• Too low of the compression
pressure
• Exhaust system blocked
• ECM fault

Diagnosis Procedure

1 . Check the engine data
(a) Ignition switch: OFF.
(b) Connect the diagnosis tool with the fault diagnosis connector (16 pins) on the lower
left of the dashboard.
(c) Ignition switch: ON, and start the diagnostic tool.
(d) Read the motor data shown on the diagnostic tool.
Check whether the data flow is normal or not.

YES>To step 2.
No >Maintenance related faults.

2 . Perform visual and external check
(a) Observe the rotation status and shaking degree of the engine
(b) At the same time, observe the swing range of the engine tachometer indicator, and
check whether it deviates from the idle target value.
(c) Observe whether it is normal idle jitter or load idle jitter. (Turn on the air conditioner,
light, hanging gear and turn the steering wheel etc.)
(d) Whether the external parts of the motor are normal or not; whether the wire connector
looses or not.

Is the inspection result normal?
YES>To step 3.
No > Exclude the problem and confirm that the phenomenon no longer exists.

3 . Check the position of the throttle
(a) Use a diagnostic tool to check whether the throttle is normal or not.