Gasoline direct injection, or GDI, is becoming more
commonplace on late model cars and light trucks. As its
name implies, fuel is injected directly into the
combustion chamber at extremely high pressure, much like
a diesel common rail system. The promise of this
technology is more power, lower emissions and better
fuel economy.
The challenge to technicians comes in understanding how
these systems work, how to diagnose them when there’s a
problem and how to service them properly. CARS attendees
who participated in the CarQuest Technical Institute’s
class “Gasoline Direct Injection Diagnosis” learned all
of that Friday morning.
Led by CTI instructor Jason Virdin, the class focused on
the theory and operation of GM’s Spark Ignited Direct
Injection (SIDI), Ford’s Gasoline Turbo Direct Injection
(GTDI) and Toyota’s D4-S. Virdin explained to his class
that, while the presentation focus was on these three,
the workbook that came with the class covered other
systems produced by VW/Audi, Saturn, Mazda, Mitsubishi
and more, making it a valuable toolbox reference.
“While the class is primarily focused on technicians
service writers and shop owners also benefit from
attending,” Virdin says. “They, too, need to understand
how these systems work, the tools required for their
service, and the (maintenance) issues that will affect
their customers.”
Virdin further explained to the group that one service
issue they need to be aware of is the increased need for
intake cleaning caused by deposit build up in the intake
tract. With no fuel to clean away deposits brought in by
the EGR system, deposits are building to severe levels
in as little as 15,000 miles.
Virdin brings 16 years of experience as a technician and
service manager with him to CTI’s Midwest and Mountain
regions. He is ASE CMAT with L1 certified, and
recognized as a California Bureau of Automotive Repair
(BAR) Certified Instructor.
