Peterbilt 579 - Page 227

DRIVING TIPS AND TECHNIQUES
Use of Tachometer
The tachometer
is an instrument that
aids in obtaining the best performance
of the engine and manual transmission,
serving as a guide for shifting gears.
Refer to
the Engine Operation and
Maintenance manual for optimum
engine rpm.
• If the engine rpm moves beyond
the maximum governed speed,
indicating an overspeed condition,
apply the service brake or shift to
a higher gear to bring engine rpm
within the optimum speed range.
• When driving downhill: shift to a
lower gear, use the engine brake
(if so equipped), and use the
service brake, keeping the engine
speed below 2,100 rpm.
When the
engine speed reaches
its maximum governed speed, the
injection pump governor cuts off fuel
to the
engine. However, the governor
has no control over the engine rpm
when it is being driven by the vehicle's
transmission, for example, on steep
downgrades. Apply service brakes or
shift to a higher gear.
Fuel economy
and engine performance
are also directly related to driving
habits:
• The best results in trip time and
fuel economy are obtained while
driving the vehicle at a steady
speed.
• Shift into higher or lower gears (or
apply the service brake) to keep
engine rpm near the lower end of
the optimum operating range.
• Avoid rapid acceleration and
braking.
Optimal Engine
Speed
WARNING!
Do not look at the Instrument Clus-
ter Display for prolonged periods or at
it repeatedly in a short period of time
while the vehicle is moving. Extended
glance durations to instrument cluster
and or overly frequent glances inside
the vehicle can cause a loss of at
-
tention to the situations on the road-
way and vehicle’s road position, which
could lead to an accident and possible
death or personal injury or equipment
damage.
The tachometer displays a green bar
just below the most efcient engine
speed for the vehicle. The placement
and size of this bar is dependent on
the engine as installed at the factory.
The driver’s general goal should
be to select a gear that keeps the
tachometer needle positioned over
the green light as much as possible
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(04/13) Y53-6047–2C 4-55