Compression System; Poor Idle Speed Performance - Hisun HS700UTV-4 Maintenance Handbook

Starter motor
Battery
Cylinder and cylinder head
Piston and piston rings
Valve, camshaft and crankshaft
Crankcase and crankshaft
Valve train
EFI system
TROUBLESHOOTING
1、Faulty starter motor
2、Faulty starter relay
3、Faulty overrunning clutch in engine
4、Broken main switch
5、Broken main fuse
1、Low battery voltage
2、Faulty battery

COMPRESSION SYSTEM

1、Loose spark plug
2、Loose cylinder head or cylinder
3、Broken cylinder head gasket
4、Broken cylinder gasket
5、Worn, damaged or seized cylinder
1、Improperly installed piston ring
2、Worn, fatigued or broken piston ring
3、Seized piston ring
4、Seized or damaged piston
1、Improperly sealed valve
2、Improperly contacted valve and valve seat
3、Improper valve timing
4、Broken valve spring
5、Seized camshaft
1、Improperly seated crankcase
2、Seized crankshaft
1、Improperly adjusted valve clearance
2、Improperly adjusted valve timing

POOR IDLE SPEED PERFORMANCE

POOR IDLE SPEED PERFORMANCE
1、Broken ECU
2、Clogged nozzle or the rupture the line from nozzle to ECU
3、Damage of engine speed signal sensor
4、Rupture of the line from engine speed signal sensor to ECU
5、 Broken inlet pressure or temperature sensor or damaged line to ECU
6、Broken air throttle or damage line to ECU.
7、Broken vice line (cable) of electrical injection
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