Start-Up Normal But Idle Speed Unstable During Warm-Up - PGO Tigra AF-125BAE Service Manual

(7) Start-up normal but idle speed unstable during warm-up

General trouble location: 1. Water in fuel; 2. Engine temperature sensor; 3. Spark plug; 4. Air throttle and
idle air bypass; 5. Air intake; 6. Idle governor; 7. Engine mechanism.
Procedure for general diagnoses:
No.
1 Check any jam of the air filter and leakage of the air intake.
Check the spark plug and its model and gap conformable to
2
specifications.
Remove the Idle governor and check the air throttle, the idle
3
governor, and the idle air bypass for any carbon deposition.
Press the engine temperature sensor connector and start the
4 engine to check any instability of the idle speed during
warm-up of the engine.
Disassemble the nozzle and check the nozzle leaking or
5 blocked, or the flow out of tolerance with a nozzle cleaner &
analyzer.
Check fuel and observe any trouble attributed to fuel just
6
added.
Check pressure of the engine cylinder and find any big
7
difference in pressure.
Connect an EMS adapter and press the power switch to check
8 voltages at Pins 5#, 10#, and 23#; check grounding at Pins 2#
and 21#.
Information Summary and Preparation 1
Operating Procedure
17
Detection
Subsequent Steps
Results
Repair the air intake
Yes
system.
No Next step
Yes Next step
Adjustment or
No
change
Yes Clean relevant parts.
No Next step
Correct circuits or
Yes
replace any sensor.
No Next step
Change the defective
Yes
nozzle.
No Next step
Yes Change fuel.
No Next step
Eliminate any
Yes mechanical trouble of
the engine.
No Next step
Yes Diagnosis assist
Repair the relevant
No
circuits.