"Dr. Gizmo"
By Phil Arendt
New Sensors Are Not The Cure
Question
1
I
have a 1994 Toyota Camry with a V-6 engine.
I think it is a 3.0-liter. The
car is in great shape even though it has 127,000 miles. I have owned it since it was new and treat it
like a baby with oil changes every 2,000 miles.
The
trouble is that the check engine light turns on in the morning every time I
start. I’ve taken the car to two different
repair shops more than once to have the cause repaired.
Each
time I take the car to a repair shop a technician finds codes that indicate a
problem with the camshaft sensor or crankshaft sensor. Both sensors have been replaced more than
once. When the sensors have been
replaced the engine does not start or run any better. After the sensors are replaced the check
engine light is off and remains off for up to two weeks. Once a week or two passes the light turns on
when I start in the morning and it remains on until the sensors are replaced
once again.
It’s
been about two weeks since the last time the sensors were replaced. The light turned on yesterday. The technician working on the car has a great
reputation. He has done some tests on the
sensors. He says they pass tests and are
working fine. He suggests that I drive
with the light turned on. He says at
some point the trouble will become worse and stall the engine. He says when it happens he will be able to
determine the cause of the trouble.
The
engine runs fine with the light on, but I’m afraid the engine will stall and
I’ll be stranded. Do you have any
suggestions? A.S.M., e-mail
Answer
1
Sure.
Swap cars with your technician. He can
drive yours until it stalls and you can drive his until your car is fixed.
It
is possible your engine will stall, but from your description of the trouble it
is not likely to occur. Since it appears
the trouble is not related to failed sensors ask your technician to consider
checking the computer. Maybe terminals
in the computer plug are loose or corroded.
Perhaps there is an internal problem.
There have been times under circumstances such as yours that tapping on
the computer turns off the check engine light.
In an instance such as this, replacing the computer resolved the issue.
Oil
Consumption Under Scrutiny
Question
2
My
2004 Acura TL with a 3.2-liter engine burns a quart of oil every 800
miles. It has 60,000 miles on it. I also have a warranty that I purchased a
couple of years ago. I took the car to
my local shop that works with warranty companies. The warranty company wants the shop to do an
oil consumption test and determine the cause of the trouble before they will
cover repairs. They also wanted service
records. I gave them copies of
everything I have done to the car including receipts and a log for all the oil
I have had to add but they still want the shop to do an oil consumption test.
I
suspect the shop and the warranty company are giving me the run-around. The shop wants me to pay for repairs. They said I can send the warranty company
receipts and I’ll be reimbursed.
What
do you think? H.T., e-mail
Answer
2
Long
ago I owned a 1970 Pinto station wagon that burned a quart of oil every 200
miles. The front passenger floor rusted
away, too. It burned oil so ravenously
it was almost sucking crude directly from an oil well. One benefit was there were no mosquitos in my
neighborhood.
At
this point don’t authorize any repairs.
Since your shop says the warranty company will reimburse you for their
work without authorization from the warranty company it is time to find a
different shop. Perhaps your warranty
company can suggest one.
Once
your car is at a repair shop, agree to warranty company requests for an oil
consumption test. After all they have
the check book. Once the test proves
excessive oil consumption, your shop must determine the cause and give the
warranty company an estimate for repair.
Since
you have provided all service records supporting regular and frequent care to
the vehicle there should not be any problem having the claim approved. Based upon all documentation and technician
findings your warranty company will respond with approval or denial of your
claim. Until then, only authorize the
shop to do procedures with warranty company prior approval.
It’s
Time For The Hook
Question
3
I
hear a popping sound in the 6.0-liter diesel engine of my 2004 Ford
Excursion. It also does not idle smooth.
There
are no technicians in my area who work on diesel engines. It’s 90 miles to my dealership. Do you know what might cause problems like
this? Do you think the engine would be
harmed if I drove to my dealership? N.N., e-mail
Answer
3
Consider
towing the vehicle to your dealership. A
condition such as this could be caused by a bent valve, broken valve spring,
bent or broken pushrod or even a burnt valve.
Troubles such as this can cause more damage to the engine if you drive
the vehicle. It’s time for a tow.
Tracking
Down Glitch In Cruise Control
Question
4
The
cruise control quit working in my 2006 Mercury Grand Marquis with a 4.6-liter
engine. I checked all the fuses with a
multi-meter and they are fine. I also
checked the connections on the cruise control unit in the engine bay. They are fine, too.
Is
there anything else I can check before I take the car to a repair shop? A.D.,
e-mail
Answer
4
There
is one. It is likely your car is
equipped with a cruise control deactivation switch on the brake master
cylinder. Since these are troublesome
and in some cases have caused fires, disconnect the plug on the unit and head
to a dealership. While this may not be
the cause of the trouble it’s better to be safe than sorry and disconnect the
plug.
Once
the car is at your dealership a technician can perform tests on the
system. More than likely the cause of
the trouble is a failed vehicle speed sensor on the transmission. If so, replacement of the part does not
require major surgery on the transmission.
Engine
Rattle Sound Is Not A Mechanical Problem
Question
5
Occasionally,
the 6-cylinder engine in my 2001 Infinity QX4 makes a rattling sound when
accelerating or when going up a hill. It
does not do it every time I drive. I
checked the oil level. It’s full. I also had the oil and filter changed. A mechanic at a local shop suggested that
cleaning the injectors might stop the noise but this service was in vain.
Do
you know what causes the rattling? S.K., e-mail
Answer
5
Your
description of the noise is somewhat vague, but it appears that the engine is
suffering from what is commonly called pre-ignition or ping. The sound is similar to marbles dropping into
a frying pan and usually occurs on acceleration.
One
condition that causes the sound is a lean fuel mixture. This does not mean the fuel used is the cause
but the ratio of fuel to air in the cylinders is lean. This can be caused by dirty fuel injectors,
air leaks or even carbon deposits in the cylinders. Cleaning the fuel injectors not only cleans
injectors but the chemical action often removes carbon deposits in the
cylinders.
Since
cleaning the fuel injectors did not cure the condition it is possible a knock
sensor has a fault, the engine timing may need resetting or perhaps fuel trims
in the computer system needs a reset or reprogramming. It is also possible carbon deposits are
excessive. If this is verified
additional chemical cleaning might resolve the issue.
Ask
your favorite technician to consider these suggestions the next time your
vehicle is in his shop.
Electric
Power Steering On The Blink
Question
6
Occasionally,
the EPS light turns on my dash panel. I
can be driving along with no lights on the panel and suddenly the EPS light
turns on. If I continue to drive the
light may stay on or it may turn off.
One time this happened I shut off the car and then turned it back
on. When I restarted the light was off.
The
car drives fine. I don’t notice anything
unusual when the light turns on. What’s
up? B.T., e-mail
Answer
6
Your
vehicle is equipped with electronic power steering. Most vehicles are equipped with hydraulic
power steering but there is industry movement to switch to electronic power
steering due to fuel economy standards and more options to place system
components in places where it would not make sense to place hydraulic
parts. The illuminated EPS light means
there is a fault in the system.
An
experienced technician with proper test equipment can determine the cause of
the issue. Since there is a factory
technical service bulletin suggesting trouble in the EPS module a technician
might need to replace the part in order to resolve this condition.
Thanks
for all of your great questions. Dr.
Gizmo can’t wait to answer more.
Phil Arendt is a columnist, consultant and
A.S.E.-Certified Master Technician.
Readers may send questions to Dr. Gizmo at P.O. Box 548, Cary, IL. 60013
or e-mail address drgizmo@drgizmo.ws. ® DR. GIZMO © 1989-2012
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