Royal Alloy GP125S, Maintenance Manual

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(2). When starting, the engine can be towed but cannot start successfully.
General fault parts:1, fuel tank without oil; 2, fuel pump; 3, speed sensor; 4, ignition coil; 5, engine mechanical parts.
General diagnosis process:
No. Inspection steps Follow steps
1
Connect the OBD diagnostic, observe the data items of the engine speed, start
engine, and observe whether there is a speed signal output. Inspect speed sensor
circuit and speed sensor
2
Remove the spark plug cap, connect the spark plug, let the spark plug on the
engine block, start the engine, check whether there was continuous blue and
white high pressure fire.
Inspect ignition system
3
Connect the fuel pressure gauge, turn on the key switch and check whether the
fuel pressure was around 250KPa. If there was no fuel pressure gauge, can
pinch the high pressure oil pipe by hand, judge the hardness.
Inspect fuel system
4
Check the pressure of the engine cylinder and observe whether there is
insufficient pressure in the engine cylinder.
Exclude engine
mechanical failure (pay
attention to check
whether engine valve
clearance is too small).