Shangchai SC27G Series Diesel Engine Troubleshooting

Low ambient temperature, low load.

Increase load to a proper degree.

The reading of water thermometer is not correct.

Regulate or replace the thermometer when required.

The thermostat does not work well or was damaged.

Replace the thermostat.

Damage of the oil cooler core.

Replace the oil cooler core.

Fault of the cylinder head gasket.

Replace the gasket.

Starting motor does not work.

(1) Poor contact of the connecting wires.

(2) Poor contact of the electromagnetic switch.

(3) Poor contact of the electric brush.

(4) Short-circuit of the starting motor.

(5) Poor electric charging or the capacity of battery too small.

Clean and tighten the terminals or joints.

Check the switch contactor and grind it by sandpaper.

Clean the surface of the reverser or replace the electric brush.

Locate and fix the short-circuit issue.

Replace the starting motor if required.

Charge the battery, or add more batteries with parallel connection.

Replace the battery if required.

The starting motor rotates but no engine starting takes places.

(1) Poor contact of the electric brush or terminal or sealing sleeve.

(2) Wear of the bearing sleeve.

(3) Partial short-circuit of magnetic field winding or electric field winding.

(4) Poor contact of the electromagnetic switch.

(5) Poor electric charging or the capacity of battery too small, and a big drop of starting motor circuit voltage.

Clean the surface and weld firm.

Make replacement if necessary.

Replace the bearing sleeve.

Locate the short-circuit and fix it out.

Check the switch contact and grind it by sandpaper.

Charge the battery and replace it if needed. Increase the wire cross section or decrease the wire length.

The starting motor gear collides with flywheel ring gear or the gear of the starting motor can not set back.

(1) The center of the starting motor is not parallel with that of flywheel ring gear.

(2) The switch contact of electro-magnetic switch fused together.

Install the starting motor again to make the two centers parallel.

Check the switch contact and grind it by sandpaper.

The starting motor keeps running when the starting button is released.

(1) The alternator belt is loose.

(2) Poor terminal contact of the alternator or/and battery.

Regulate it again.

Repair.

Alternator can not charge.

(1) The alternator belt is loose.

(2) Poor terminal contact of the alternator or and battery.

(3) Rotor failure (magnetic coil)

Adjust the belt to a proper tension.

Clean or tighten all terminals and connects of the alternator and battery, and replace wires and terminals and joints if required.

Change the rotor.

Too low alternator voltage or abnormal alternator charge.

(1) The drive belt is loose.

(2) Poor terminal contact of the alternator or/and battery.

(3) The voltage regulator of the alternator is damaged.

(4) Rotor failure (magnetic coil)

(5) Burn of the rectifier diode.

Adjust the belt to a proper tension.

Clean and tighten all the terminals and connects of the alternator and battery.

Replace wires and and terminals and joints if required.

Replace the voltage regulator.

Too big voltage of the alternator.

(1) Poor contact of the connector of the alternator or its voltage regulator.

(2) Fault of the alternator voltage regulator.

Tighten the all connectors.

Change the regulator.

Abnormal noise from the alternator.

(1) Abrasion or damage of the drive belt.

(2) The driver belt is loose.

(3) The centers of the drive belt and pulleys are not in alignment.

(4) Wear of the bushing.

(5) The armature or rotor bent.

(6) The alternator rectifier circuit is short.

Change the belt.

Adjust the belt to a proper tension.

Adjust and make them in alignment.

Change the alternator.

Change the alternator.

Change the alternator.

Fuel injection pump does not supply fuel.

(1) No fuel in the fuel tank.

(2) There is air in the fuel system.

(3) Block of the fuel filter or fuel pipes.

(4) Failure of the fuel transfer pump.

(5) Seizure of the plunger and barrel.

(6) Poor seal at the fuel delivery valve seats.

Add fuel in time.

Prime the fuel system, refer to Section 5.3 for the procedure.

Replace the fuel element and clean the low pressure fuel pipeline.

Replace the fuel transfer pump.

Let a professional serviceman check and repair the plunger and barrel assembly, and make replacement if necessary.

Let a professional serviceman check and repair the fuel delivery valve seats, and make replacement if necessary.

Uneven fuel supply.

(1) There is air in the fuel pipeline, resulting in inter-mitten fuel supply.

(2) Break of the delivery valve springs.

(3) Wear of the delivery valve-seats.

(4) Impurity leads to the seizure of plunger.

(5) Fuel inlet pressure too small.

Priming the fuel system and refer to Section 5.3 for the procedure.

Replace the fuel injection pump.

Let a professional serviceman replace the fuel delivery valve seats.

Let a professional serviceman clean the plunger and barrel assembly and make replacement if necessary.

Check the strainer of the inlet connector in the fuel transfer pump and the fuel filter for block. Clean and replace them if necessary. And maintain them according to the maintenance plan.

Insufficient fuel supply.

(1) Fuel leak at the delivery valve assembly.

(2) Block of fuel strainer on the fuel transfer pump or block of fuel filter.

(3) Wear of plunger and barrel assembly.

Let a professional serviceman check the delivery valve assembly, and replace the assembly when required.

Clean the strainer, replace the fuel filter.

Let a professional serviceman replace the plunger and barrel assembly.