Service manual

Information Summary and Preparation 1
20
(10) Start-up normal but idle speed too high
General trouble location: 1. Air throttle and idle air bypass; 2. Vacuum tube; 3, Idle governor; 4. Engine
temperature sensor; 5. Ignition timing.
Procedure for general diagnoses:
No. Operating Procedure
Detection
Results
Subsequent Steps
1 Check the throttle cable for jammed or too tight.
Yes Adjustment
No Next step
2
Check the air intake system and the connected vacuum tube
for any leakage.
Yes
Repair the air intake
system.
No Next step
3
Remove the idle governor to check the air throttle, the idle
governor and the idle air bypass for any carbon deposition.
Yes Clean relevant parts.
No Next step
4
Press the engine temperature sensor connector and start the
engine; check if the engine’s the idle speed is too high.
Yes
Correct circuits or
replace any sensor.
No Next step
5
Check if mechanical ignition timing of the engine is
conformable to specifications.
Yes Next step
No
Correct ignition
timing.
6
Connect an EMS adapter and press the power switch to check
voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Yes Diagnosis assist
No
Repair the relevant
circuits.