Fixed Ops_Jan-Feb 2015_GDI

Featu r e
January / February 2015 || Fixed Ops Magazine
Digging For Answers
GDI E n g i n e C o m p l a i n t s Of t e n My s t e r i o u s , H a r d t o R e s o l v e Many modern vehicles powered by
Gasoline Direct Injection (GDI) engines
are showing up in Service Departments
with mysterious complaints: high oil
consumption, misfires and performance
loss. These problems can put the diagnostic skills of even the best Technicians
to the test.
OEMs developed GDI engines to meet
2016 CAFE fuel economy standards and
they’ve been increasing in use since
2000. The technology, however, has
been around since WW II. MercedesBenz used it in the early ‘50s for its
300SL Gullwing, which won at LeMans
in 1952.
Diagnosing and remedying these engines’ issues early is important. Problems can affect engine performance in
as little as 3,000 miles. Neglected treatment may require a costly upper end
teardown or vigorous mechanical cleaning to restore vitality.
One reason GDI problem diagnosis is
often elusive is that some of the diagnostic skills to identify it are long outof-practice. For instance, the industry’s
heavy reliance on sensor codes and
scan diagnostics have eroded many
Techs’ ability to diagnose based on observation, knowledge and instinct.
A dealer (and OEM) can only hope that
the repairs will restore the vehicle owner’s brand trust.
Shawn Crow, Service Manager for Bob
Chevrolet-Buick-CadillacGMC near Wheeling, West Virginia, told
me his shop sees GDI engine issues
every day. “It involves ’07 models forward,” he said. “It’s even more a problem in turbo versus naturally aspirated
GDI engines because the intake gases in
turbo engines are even hotter.”
Pat Goss, Motorweek’s resident master Technician and Owner/Operator of
Goss’s Garage near Washington, D.C.,
for the last 43 years, has told me that
part of the diagnostic challenge is that
many Technicians have not been educated about issues associated with GDI
p. 60
By Jim Leman
Also disconcerting, Goss said, is that
many techs and motorists still check
a vehicle’s tailpipe for bluish exhaust.
That diagnosis for cylinder oil burning
was valid in the days before cars had to
use catalytic converters. These devices
burn away all gases entering them, leaving zero telltale oil smoke at the tailpipe.
“Many modern vehicles powered by Gasoline
Direct Injection (GDI) engines are showing
up in Service Departments with mysterious
complaints: high oil consumption,
misfires and performance loss.”
January / February 2015 || Fixed Ops Magazine
Problem details
GDI engines burn leaner than port fuel
injection engines, a 40-to-1 versus 14.7to-1 air-to-fuel ratio. This leaner mixture
results in more conservative fuel usage
but contributes to much hotter engine
operating temperatures.
There are several GDI engine concerns:
• Higher cylinder temperatures and pressures released into the crankcase accelerate oil vaporization. Eventually this
causes oil droplets to coat intake valves.
• Cylinder injector spray position means
fresh fuel is not sprayed onto intake
valves to flush away vapor build-up.
This build-up can accumulate and bake
onto intake valves in as little as 10,000
miles (16,000 km).
• Rings can become stuck into their
lands by carbonized oil sludge. This can
prevent these engine’s low-tension rings
from properly sealing the piston. This
also causes sludge, oil and fuel deposits
to bake onto piston tops.
• Since inception, GDI engines have had
known problems with coking – a buildup
of cooked fuel deposits that foul injectors.
p. 62
Konrad DeLong is a former regional field
engineer for General Motors. He now is
Development Coordinator for Lubrication Specialists, Inc. of Houston. In both
roles, he has learned well how major vehicle engine problems, like those showing up in GDI engines, can shake consumer confidence.
“Customers would bring vehicles into
the shop complaining of misfires or
performance lags, but when Techs run
diagnostics, the PCM [power control
module] might show a diagnostic trouble
code but no indicator of the cause,” DeLong recalled from his GM experiences.
“The Technician would perform an intake
cleaner service perhaps, but the vehicle
would return with the same problem,” he
added. “The cleaners and the cleaning
process used couldn’t reach these deposits and did little to address the stuck
rings and crankcase vapor deposits that
were the core issues.
“Having to tear down an engine to address a problem can be a real confidence
shaker for the customer, causing loss of
trust in the brand, so remedying the situation correctly is critical,” he said.
The National Highway Traffic Safety Administration believes that 60 percent of
the fleet by 2016 will use GDI technology. Service Departments can expect
to see an increasing volume of GDIpowered vehicles in their shops. OEMs
reluctance to talk about these engines’
issues, Goss believes, has hampered
techs’ ability to understand, diagnose
and remedy these problems for their
To be fair, OEMs are studying and hoping to resolve GDI combustion chamber and valve design to prevent these
issues. For instance, General Motors
Service bulletin document ID 3650687
addresses “engine misfires due to major
carbon deposits on the intake and / or
exhaust valves.” It covers 17 GM models
from 2009 to 2014. In other cases, motorists have sued Ford for performance
issues related to its EcoBoost GDI engine. According to reports, the National
Highway Traffic Safety Administration is
However, as is often the case, the aftermarket provides a remedy.
January / February 2015 || Fixed Ops Magazine
Solution details
Experts’ observations and my personal
research of literature on the topic led to This site bristles with
photography, obtained by borescope, of
what the combustion chambers of these
engines can look like even after only a
few thousand miles. Other borescope
studies on these engines show:
• A crankcase cleaner (added to the
engine and the engine operated for 15
minutes prior to an oil and filter change
and then introduced as supplement
treatment with the fresh oil change)
to loosen and dissolve heat-baked oil
sludge in the crankcase, piston rings
and oil screens and passages, rocker
arms and other critical areas of engines.
liver a solid, proven maintenance investment for these vehicles.”
• Oil sucked into the air intake and into
the turbocharger at 6,454 miles on a
2012 Porsche 4.8L
• An engine-performance restoration
treatment to control future oil deposits.
How advisors present this remedy is important, Crow said.
GDI engines deliver superior fuel economy, performance and reduced emissions. However, these advantages come
with some potentially costly problems.
“Presenting customers a supplement
treatment solution can be a fine line,”
said Crow, a former master-certified
GM Technician. “No customer who just
purchased a new vehicle powered by a
GDI engine wants to hear that more than
routine oil and filter maintenance may be
Finally, where a solution is available and
presented knowledgeably for GDI engine performance problems – and its
use in their engine is agreed to by vehicle owners -- this noninvasive remedy
may save them frustration, money and
lost confidence and get their vehicles
running like new again.
• Intake port deposits at 21,000 miles on
a 2009 BMW 3.5L
• Cylinder scoring from deposits at
25,600 miles on a Ford F-150 3.5L EcoBoost
• Sticky deposits on pistons in a 2013
Porsche 4.8L after 6,454 miles
Goss and Crow described a supplements-based treatment they have found
to be effective in remedying GDI issues.
One or both described the service they
do on these cars as:
• A detergent- and additives-rich fuel
tank and fuel system cleaner to clean
deposits in the fuel line, intake manifold,
fuel injectors, valves and combustion
p. 64
“This is especially true now that new
GM models come with a two-year free
maintenance program. Why then should
a customer want to pay for an out-ofpocket preventive service? However,”
Crow stressed, “treating GDI engines
with a motor oil additive that reduces
acidity and sludge buildup between oil
changes and fuel tank and valve cleaners is the only way we’ve found to de-
Goss of Goss’s Garage agreed. “We
have had tremendous luck with this
treatment for these engines, which uses
a chemical engine cleaner that dissolves
and removes deposits from piston rings
to help restore compression,” he said.
Round Lake, Illinois-based Jim Leman, who has faced carbon and sludge
buildup in the ‘30s and ‘40s engines he
has rebuilt, writes often about automotive
technologies and automotive retail.