Holiday 2002 NEPTUNE, Owner'S Manual

Page: 37 / 344

Driving & Safety
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2 0 0 2 N E P T U N E
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When descending a long grade, use the braking force of the engine and the
auxiliary braking device, i.e. engine Jake Brake or exhaust Pac Brake, to main-
tain a safe, slow speed. Do not rely entirely on the service brakes to slow the
motorhome when descending long grades. "Pumping" and riding the service
brakes is not recommended when descending a grade, as the brakes can over-
heat; over-use can result in the loss of brake effectiveness.
If it is necessary to use the service brakes for additional braking, use a mod-
erately heavy pressure on the brake pedal to reduce the motorhome speed and
then release the brakes.
Before descending a grade, downshift the transmission to a lower gear and
use the engine to slow the vehicle. Monitor the motorhome speed while
descending the grade.
Many factors contribute to the amount of fuel consumed during driving.
Driving styles, wind resistance, terrain, vehicle weight, and engine-driven
accessories are some of the factors that affect the fuel economy. Use the fol-
lowing guidelines to help increase fuel efficiency:
• When starting out, use smooth, easy starts by gradually increasing
speed, rather than using excessive throttle and accelerating quickly.
• While operating the motorhome, keep the engine at a low to mid RPM
range of 1100 to 1500 RPM. Doing so will use less fuel than operating
at higher rpm.
• While driving in rolling hills, avoid downshifts when going uphill, and
use the downhill grades for accelerating, rather than the throttle.
• Avoid extended idling to allow the engine to warm. Only wait long
enough for normal oil pressure to register and the engine coolant tem-
perature gauge to begin to climb. Whenever coolant temperatures are
below 160°F (as in an idling engine), diesel fuel does not burn well or
completely. This causes carbon buildup and fuel slobber from the
exhaust. If the engine coolant temperature becomes too low, raw fuel
will wash the lubricating oil off the cylinder walls and dilute the
crankcase oil.
• Excessive idling (more than 10 or 15 minutes), carbon can clog injec-
tor spray holes and piston rings and cause the valves to stick. Operate
the transmission with the
ECON MODE switch set to Economy
whenever possible; this allows for earlier shifts and enhanced fuel
economy.
• Follow the maintenance schedule for the chassis. Proper maintenance
will lead to enhanced fuel economy, motorhome performance, and
longevity.
Descending a Grade
Fuel Economy