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film inside the tank, whether that's water or some
kind of microorganism that's growing. "
Fuel injectors represent another area technicians
should pay close attention to.
" High-pressure common rail fuel injectors are
susceptible to abrasive wear particles typically
found in the 4- to 15-micron range, " said Jay
Stephenson, North American training leader for
Cummins Filtration, a global leader in air, fuel,
hydraulic, and lube filtration. " Sacrificing filter
performance to save a few dollars can come back
to haunt a fleet when the fuel system starts experiencing
problems. "
Stephenson pointed to an example where failing
injectors can lead to fuel washing the lubricating
oil off the cylinder walls, which enables metalon-metal
contact between the power cylinder
components during combustion.
" Injectors that are not maintaining correct
injection pressures will spray as a fine mist, struggling
to atomize fuel properly, " Stephenson said.
" The first signs of injector wear are hard engine
starts and rough idling. But as this continues,
increased fuel consumption, loss of horsepower,
and increased emissions are common signs that
injector wear is in advanced stages and may be
nearing failure. "
Malfunctioning injectors can also lead to an
abundance of soot due to over-fueling. " That can
prematurely clog the diesel particulate filter (DPF)
and cause the aftertreatment system to throw
codes, " Stephenson said. " In terms of the filter
directly, if premature plugging or short filter life
are experienced, it's often an indication that the
cleanliness of the diesel fuel in the tank is poor. "
Tips on proper fuel filtration
As Cummins Filtration's Stephenson pointed out,
the only proven method for combating dirty fuel
is through effective filtration techniques using a
combination of multi-stage filtration fuel filters
when possible: stage 2 (on-engine), stage 1 (fuel/
water separators which are typically chassis-mounted),
and stage 0 (bulk fuel storage tanks) fuel filters.
For fuel fill-ups on the road, stage 0 filtration
is not realistic. But for fleets operating their own
fueling sites, Stephenson said stage 0 filtration
and routine bulk tank storage cleaning are best
practices for ensuring cleaner fuel.
For any fleet, Stephenson said it is always imperative
to use a stage 1 fuel filter/water separator,
such as a DAVCO Diesel Pro or Fuel Pro unit, in
combination with a stage 2 on-engine fuel filter,
to ensure that the stage 2 fuel filter can achieve
its rated service interval. " Without a stage 1 fuel
filter/water separator, the stage 2 filter will take
the brunt of all fuel contamination and will be
quickly overwhelmed, " Stephenson explained.
Some Cummins Fleetguard stage 1 fuel/water
separator filters are constructed with a three-stage
water-removal architecture to combat the severe
challenges of water in diesel fuel. Stephenson said
this filter design also helps fleets meet the requirements
for advanced water removal on 2017 and
newer U.S. EPA model engines.
Even when utilizing premium-quality fuel
filters, technicians must still adhere to proper
filter maintenance and changeout intervals.
» Rislone Hy-per Diesel Complete Fuel
System Treatment is an all-in-one diesel fuel
additive. Each bottle contains important
fuel quality and performance improvers such
as a complete fuel system cleaner, anti-gel
additive for cold weather, fuel stabilizer and
conditioner, cetane power booster, ULSD sulfur
substitute, and upper cylinder lubricants.
Photo courtesy of Rislone
" Engines
that have a fuel/water
separator
should be drained on a periodic basis, "
ExxonMobil's Rivera said. " The frequency depends
on the amount of fuel the truck consumes, as well
as the amount of fuel a fleet with on-site storage
purchases. As a general rule, the fuel/water
separator should be drained at the same time the
regular fuel filter is changed. "
Fuel filter replacement intervals will vary
based on several factors. " How often a fuel
filter must be changed depends on geography,
fuel type, and other factors, " Rivera said. " I see
recommended intervals ranging from 12,000 to
25,000 miles depending on the OE. Know what
the recommended interval is, and always use an
OE or OE-quality filter. "
Before a technician even touches a fuel filter,
River said it's critical to clean the filter housing
and surrounding area to remove any dirt or other
contaminant buildup. " It's really important to
have good housekeeping procedures to prevent
contamination of the new filter you're installing, "
Rivera added.
A little additive can
go a long way
Clean, high-quality fuel is key to maximizing vehicle
performance. Trimble, of Hot Shot's Secret, said
fleets should search for a fuel that is consistently
strong in the following categories:
ÜCetane number
ÜLubricity
ÜCorrosion protection
ÜInjector deposit control
ÜLow-temperature operability (October to March)
ÜFilter-blocking tendency
ÜThermal stability
" Running a fuel without the proper cetane
number can result in lower fuel economy,
rougher operation, and less power, " Trimble
said. " Fuel without proper lubrication can lead
to catastrophic failures such as fuel pumps and
injectors. Diesel fuel that cannot adequately
control injector deposits will lead to deposits
forming both internally and externally on fuel
injectors. These can lead to fuel delivery issues,
rough operation, and wear. "
Fuel additives can help combat potential issues.
" General-purpose diesel fuel additives are
designed for use all year, while others are specifically
formulated for certain seasons or particular
issues, " Rislone's Parks explained. " For example,
cold-weather driving requires the use of anti-gel
additives to keep fuel from gelling and clogging
the fuel tank and filters. This can be especially
important in the winter when southern trucks
travel north. There are also special water removers
that work in combination with anti-gel additives
to keep fuel lines from freezing up. "
Cetane additives also exist to help boost
engine power. Upper cylinder lubricants help
reduce friction. " This is especially helpful in
older diesel engines that were not specifically
designed for ultra-low sulfur diesel (ULSD) fuel, "
Parks pointed out. " A lubricant also keeps fuel
pumps running smoothly. "
Sometimes a fleet has more than one fuel-re»
Hot Shot's Secret Diesel Extreme
can help reduce the need for DPF
regen cycles by reportedly restoring
lost engine power by up to 87%.
Photo courtesy of Lubrication Specialties, Inc.
lated issue to contend with. In those instances,
Trimble said a fully-formulated additive that isn't
full of fillers can be an efficient and cost-effective
solution. Examples include Hot Shot's Secret
Everyday Diesel Treatment and Rislone Hy-per
Diesel Complete Fuel System Treatment.
ExxonMobil's Rivera reminded that it's always
essential to refer to the OE manual for advice on
what should and shouldn't be used.
" Some manufacturers don't allow for the use
of certain aftermarket fuel additives in their
engines, " Rivera pointed out. " Some OEs feel that
diesel fuel that meets ASTM D975 is sufficient for
most conditions.
" At the end of the day, an individual fleet has
to manage this decision for itself, " Rivera continued.
" If you have on-site bulk tanks and are
having issues with water intrusion or microorganisms
affecting your fuel, your next recourse
is going to be some kind of additive treatment. In
a perfect world, 2D gets refined and is delivered
to the end-user in a refined condition. But time is
the enemy. Add to that some severe fluctuations
in temperature, and some kind of degradation
is likely to occur. Plus, you never know when
other types of contaminants might enter the
supply chain. "
That is precisely why fleet technicians should
always be on the lookout for symptoms of fuel-related
issues.
August 2021 | FleetMaintenance.com
29
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august2021

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