Light duty diesels today are far more sophisticated than they were only a few short years ago, and diesel service today is correspondingly more complex. Older diesel systems were basically mechanical, and most repairs involved identifying the problem, performing mechanical repairs and replacing any parts needed on-site, or taking the parts to a service specialist who would repair them for reinstallation.
"Today's diesels in lighter duty vehicles increasingly utilize computerized engine management systems and are electronically controlled, and equipped with sensors typically requiring at least a scan tool to identify trouble codes-just like with gasoline engines. And almost without exception, they require specialized training for the technicians who service them-training on the modern systems is absolutely crucial for proper diesel service," notes Al Krenz, director of service for Robert Bosch Corporation, a leading supplier of diesel systems.
With a tradition of providing on-engine/on-vehicle diesel training to independent service dealers through the Bosch Diesel Service Center (DSC) program, Bosch knows a thing or two about light diesel maintenance.
"Much of our work is with fuel systems, and mostly deals with customer driveability concerns," says Chuck Oliveros, a Bosch-trained diesel technician from Williams Diesel Service in Ocala, FL. "Typical symptoms include: no start; hard to start; rough running; and lack of power. We frequently repair, recalibrate or replace injectors and fuel-injection pumps."
TIPS & TRICKS
According to Keith Atkins, senior training author for Clinton Township, MI-based Tweddle Litho Company, and Jim Weiss, training team leader for Tweddle, technicians who work on light-duty gasoline engines can easily make the switch to servicing the new generation of light duty diesel engines. All technicians need to know, they say, are a few new "tips & tricks."
In their work for Tweddle Litho, a major publisher of automotive service training materials, Atkins and Weiss have helped develop service training for International Truck & Engine's Ford Powerstroke diesels, and the new 2.8L diesel being offered in the 2005 Jeep Liberty and Dodge Sprinter. Atkins' first advice for light duty technicians is to become familiar with new emission-control technology:
"The new low sulfur diesel fuel has five to seven times less soot-style emissions than previous fuel mixtures," he says. "We're looking at 3,000 ppm in previous diesel engines to where now we have about 500 ppm.
"The next thing that also helps emissions on diesels are the electronic engine controls," he continues. "Fuel delivery systems are updated with common rail-style fuel injection, where they have computer control over timing and volume. This is very precise, and helps mileage and emissions in diesel engines.
"The last item being used is the particulate trap, which is actually a filter or a scrubber, where the exhaust passes through the system and it removes the soot and the smell from the exhaust," he explains. "They have a couple types: on one you would have to clean that filter or scrubber, and the other type is a new design where they put an electric current through a heating element to burn off particle collection and clean the device."
These issues are sure to become more relevant to fleets with light-duty vehicles, as small "clean" diesels are showing up in growing numbers of light vehicles in the U.S.
"There is a greater acceptance, and part of that is due to fuel prices and improvements in performance," says Weiss. "Keith recalled that his dad had a VW Rabbit diesel in 1981, and the vibration would literally shake the dashboard loose at idle. It got 51 miles to the gallon, but if you were sitting there at a light it was unbearable."
"There are huge improvements in the noise, the smoke and the overall performance," says Weiss. "With the new fast light off glow plugs, you don't have the lag time for start up, you don't get the smoke on start up, you don't get the noise. It's getting to the point that it's indistinguishable from a gasoline engine in terms of what the driver's going to feel."
New engines mean new training challenges.
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