Service manual

Information Summary and Preparation 1
21
(11) RPM low or stall during acceleration
General trouble location: 1. Water in fuel; 2. Inlet pressure sensor & air throttle sensor; 3, Spark plug; 4.
Air throttle & idle air bypass; 5. Air intake; 6. Idle governor; 7. Nozzle; 8. Ignition timing; 9. Exhauster.
Procedure for general diagnoses:
No. Operating Procedure
Detection
Results
Subsequent Steps
1 Check the air filter for any jam.
Yes
Check the air intake
system.
No Next step
2
Connect a fuel pressure gauge before the fuel inlet of the nozzle;
start the engine to check the fuel pressure at 300kPa or so during
the idle status.
Yes Next step
No
Repair the fuel supply
system.
3
Check the spark plug in the cylinder and its model and gap
conformable to specifications.
Yes Next step
No
Adjustment or
replacement
4
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
5 Check the inlet pressure sensor, the air throttle and circuits.
Yes Next step
No
Correct circuits or
replace any sensor.
6
Disassemble the nozzle and check any leakage or jam in the
nozzle with a nozzle cleaner & analyzer.
Yes
Replace the defective
nozzle.
No Next step
7 Check fuel and observe any trouble attributed to fuel just added.
Yes Change fuel.
No Next step
8
Check if ignition timing of the engine is conformable to
specifications.
Yes Next step
No Correct ignition timing.
9 Check the exhauster for exhaust normally discharged.
Yes Next step
No
Repair or replace the
exhauster.
10
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.