GENERAL INFORMATION
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1. The injector is clogged
2. The pump pressure is not enough
3. ECU program chaos
4. ECU damage
5. The pressure sensor, oxygen sensor, solar term door position sensor fault
ENGINE
Engine Smoke
The color of engine smoke can help diagnose engine problems or operating conditions
Black smoke
Black smoke is an indication of a rich air/fuel mixture
Blue smoke
Blue smoke indicates that the engine is burning oil in the combustion chamber as it leaks past worn
valve stem seals and piston rings. Excessive oil consumption is another indicator of an engine that is
burning oil. Perform a compression test to isolate the problem.
White smoke or steam
It is normal to see white smoke or steam from the exhaust after first starting the engine in cold
weather. This is actually condensed steam formed by the engine during combustion. If the UTV is
ridden far enough, the water cannot collect in the crankcase and should not become a problem. Once
the engine heats up to normal operating temperature, the water evaporates and exits the engine
through the crankcase vent system. However, if the UTV is ridden for short trips or repeatedly started
and stopped and allowed to cool off without the engine getting warm enough, water will start to collect
in the crankcase. With each short run of the engine, more water collects. As this water mixes with the
oil in the crankcase, sludge is produced. Sludge can eventually cause engine damage as it circulates
through the lubrication system and blocks off oil passages.
Large amounts of steam can also be caused by a cracked cylinder head or cylinder block surface
that allows coolant to leak into the combustion chamber. Perform a Coolant System Pressure Test.
Low Engine Compression
Problems with the engine top end will affect engine performance. When the engine is suspect,
perform the leak down procedure in this chapter and make a compression test . Interpret the results as
described in each procedure to troubleshoot the suspect area. An engine can lose compression
through the following areas:
1. Valves:
a. The gap between the valve is not suitable.
b. Incorrect valve timing.
c. Worn or damaged valve seat surfaces.
d. Bent valves.
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