1.2L REVOTRON ENGINE
79
HLA noise can be heard as repeated tappet like
noise when engine is running at low idle speed.
Following procedure is recommended to eliminate
the noise.
Raise the Engine speed to 500rpm without
load (Vehicle stationary) to bleed the hydraulic
chamber of HLA. The noise should disappear
in 15-30 seconds.
If the noise still persists, run the engine further
under same condition (no load at 500 RPM)
for several minutes. The noise should
disappear in 3 to 30 mins, in few cases.
• In a very rare case if the noise is still heard,
the HLA is stuck in compressed position and
has to be replaced
6. VCT (Variable Cam Timing)
The variable cam timing (VCT) control system
controls the opening/closing timing of the intake
valve and exhaust valve in accordance with driving
conditions; improving engine output and reducing
fuel consumption and emissions.
The variable cam timing (VCT) controller adjusts
cam shaft rotation relative to crank shaft rotation in
accordance with amounts of oil in its oil chambers,
controlling the opening/closing timing of the intake
or exhaust valve. The amounts of oil in the oil
chambers are managed by controlling the oil flow
control valve in accordance with driving conditions.
It improves the engine performance significantly,
providing greater engine output, better fuel
economy and reduces emissions.
7. Solenoid Valve (Oil Control Valve)
The variable camshaft timing oil control solenoid
is attached to camshaft and is hydraulically
operated in order to change the angle of the
camshaft relative to Crankshaft Position. The
variable camshaft timing oil control solenoid is
controlled by the control module. The control
module sends a pulse width modulated 12 volt
signal to a variable camshaft timing oil control
solenoid. The solenoid controls the amount of
engine oil flow.
.