
i. Incorrect ignition timing, adjust it;
j. Vacuum pressure sensor failure, repair or replace it.
5. Idle Speed Is Not Stable, Tends to Flame-
out
(1) Symptom of fault:
Engine starts normally, but idle speed is not stable either for
cold auto or warm auto, idle
revolution is too low and tends to flameout.
(2) Cause of fault and elimination
a. Idle control valve works poorly, repair or replace it;
b. Idle revolution is a bit low, idle control valve is defective or
maladjusted, troubleshoot to recover normal condition;
c. Water temperature sensor failure, repair or replace it;
d. Poor airtightness of intake system, repair it;
e. Inaccurate ignition timing, adjust it;
f. High voltage spark too weak, carbon accumulation in
spark plug or electrode gap too small,
repair, remove or adjust it;
g. Pressure sensor failure, repair or replace it;
h. Compression pressure of the cylinder too low, repair it;
i. Pressure of oil passage too low, repair it;
j. Air filter clogged, clean, eliminate or replace it;
k. Poor atomization of injector, there are leaking, blocking
or large difference between injections, repair it;
(3) Fault diagnosis procedure (Fig. 359):
Fig. 359 Fault Diagnosis and Troubleshooting Procedure for Instability and Flameout at Idle Speed
Idle speed is not stable, tends to flameout
Yes
Repair and eliminate
Poor
Dismantle, check or replace
Does not work
Check whether tightness of intake system is good
Normal
Check whether idle control valve works or not
Works
Readjust initial idle speed
Normal
Normal
Normal
Normal
Normal
Normal
Check spark plug
Adjust gap or replace
Check fuel pressure
Check injector
Abnormal
Check pressure sensor
Check cylinder compression
Check and adjust throttle gap
Poor
Check electric petrol pump, fuel
pressure adjuster and filter
Abnormal
Abnormal
Abnormal
Replace
Replace
Detach and check the engine
168
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...