"Dr. Gizmo"
By Phil Arendt
Many Issues Can Cause Engine Stalls
Question 1I have a 2007 Mazda 3 with a 2.0-liter 4-cylinder engine and automatic transmission. It has 127,000 miles. It’s in great condition. I’ve owned it since it was new and I follow the factory recommended maintenance schedule. It’s well maintained and looks like new.
Recently, the dash light
came on. Since then when I accelerate
the engine feels like it is sputtering and it has little pickup. If I accelerate slowly it’s not as bad.
I went to an auto parts
store to have the codes read. The codes
found are PO300 and P2177. The partsman
said the trouble could be the gasoline. He
suggested that I take the car to a repair shop to have it tested. He also said that the spark plugs might be
bad.
I went to a repair
shop. Tests found the gas is ok. The mechanic did some other tests and found
the same codes as the partsman. He said
that probably the spark plugs are misfiring because of a lean fuel
mixture. He needed to do more testing
but I did not give him the okay.
Do you know what causes the
lean mixture? K.J., email
Answer 1
No, but I can tell you that
your technician has ruled out problems with gasoline. Also, a lean fuel mixture could be caused by
vacuum leaks at the intake manifold gasket, cracked manifold, a failing mass
air flow sensor, cracked vacuum line, failed brake vacuum booster, failed
oxygen sensor, failing fuel pump, faulty fuel pressure regulator, dirty mass
air flow sensor, failing fuel injectors and more.
To find the exact cause the
best thing to do is ask your favorite technician to perform tests. Code PO300 points towards multiple spark plug
misfires. This does not necessarily mean
the spark plugs need replacement. More
than likely the misfire is due to a lean fuel mixture. This means that there is too much air or not
enough fuel in the air/fuel ratio going into the cylinders and not faulty spark
plugs.
Code P2177 refers to a lean
condition caused by about a dozen issues including those I have already
mentioned.
Dr. Gizmo Is Wrong
Question 2In a recent column, I read with interest your answer to N.L.D. As soon as I read your answer I knew you were wrong. I have a 2002 Dodge Ram pickup with 65,000 miles. It stalled just like the other person’s vehicle. I spent $300 at different shops trying to have the problem repaired. None of the shops had any idea what was wrong. Then I went to a friend who does tune-up work. He drove the truck and knew right away that the problem was caused by a bad oxygen sensor. He explained how the sensor works and said that it causes the engine to shut off. He said that the spark plugs have nothing to do with stalling. Since he replaced it, the truck has not been any trouble.
Can you tell the person with
the Cherokee? W.U., Bayport, Minn.
Answer 2
Thanks for bringing this to
my attention. Hopefully N.L.D. is
reading the column today. He or she owns
a 2010 Jeep Grand Cherokee that stalls.
It’s equipped with a 3.7-liter engine and has 73,000 miles. A shop technician suggested tuning the engine
with new spark plugs. N.L.D. did not
have the work done because a friend said plugs don’t need replacement until the
truck hits 100,000 miles. N.L.D. wanted
to know what causes stalling.
In my response I said there are
many reasons for an engine to stall.
Certainly I can’t list every possible cause in this column. You are correct a faulty oxygen sensor can
indeed cause an engine to stall. Also, in
my response, I did indeed suggest replacing the spark plugs because according
to the factory maintenance schedule the plugs needed replacement at 30,000
miles and the vehicle has 73,000.
Excessively worn spark plugs can cause an engine to stall.
Also as a caveat, I added an
additional service that was overdue. I
suggested a transmission flush because according to the factory schedule that
was due at 60,000 miles.
Poor Electrical Connections
Turn On Charging Light
Question 3The charging light on the dash of my 2001 Nissan Pathfinder is on but dimly. I took the alternator to an auto parts place for testing. Tests found it is charging fine. I also asked them to test the battery. It’s fine too. The partsman suggested that I go to a repair shop but I’m not in a position to spend a lot of money on the truck right now.
Sometimes as I drive the
dash light becomes bright and sometimes it turns off. Do you think the trouble is in the dash? Since the battery does not die is this
something I should have repaired right now or can I put it off? T.F., email
Answer 3
The fact that the battery is
not going dead is a good sign but it may not be receiving a full charge. On an extremely frigid day such as we
recently experienced the battery just might not have the oomph to start the
engine. However, you might let it slide
for a while.
The light issue might be
caused by a poor connection in the dash.
It’s also possible a poor ground connection or a poor connection in the
relay center under the hood might be the cause.
When you are able to take the vehicle to a shop ask your technician to consider
these suggestions.
Oil Leak Develops After Oil
Change
Question 4There is oil dripping on my garage floor near the driver’s side. It’s where I park my 2007 Mini Cooper. I checked the oil level. It’s a little low.
I have noticed the leak
since the last oil change when the car had 117,000 miles on it. Now it has 119,000. I called the shop that did the oil change but
they said they don’t do big repairs such as oil leaks because they are only a quick
oil change shop. They suggested I take
the car to a full service repair shop. I
did as suggested.
The second shop said the oil
filter housing gasket is leaking and needs replacement. Is this something the quick oil change shop
damaged? Y.D., email
Answer 4
There are a couple of
gaskets on the oil filter housing. One
is located where the oil filter housing mates with the engine. There is another that should be replaced when
the oil filter is replaced.
If the gasket at the oil
filter housing and engine mating surface is leaking, the likely cause is normal
wear and tear. If the large rubber “O”
ring at the oil filter is leaking, the seal might be defective, damaged or
improperly installed. If so, the shop
that replaced the filter should resolve the issue at no cost to you as this
seal is replaced with every oil filter replacement.
Aftermarket Remote Start
System Impairs Starts
Question 5I have a 2007 Toyota Tacoma that won’t start. Well it starts and then dies. I had the truck towed to a repair shop where a technician found a code for the antitheft system. He has done many tests but can’t find the cause of the trouble. At first he thought the engine computer was causing the trouble. He does not want to replace it unless he is absolutely sure. He also thinks the remote start that I had installed about four years ago is the cause of the trouble. He wants to remove it and go from there.
I really enjoy the remote
start feature. My truck is parked
outdoors and it’s nice to get into a warm vehicle. Does removing it seem right to you? T.B., email
Answer 5
Your truck is equipped with
a factory installed Immobilizer antitheft system that helps deter vehicle theft. Apparently, it is impairing engine
starts. This indeed sometimes occurs
when there is a fault in an aftermarket add-on such as a remote start system.
To find out for sure if a
fault in the remote start causes the trouble your technician does not have to
remove it. He instead can disconnect it
and reprogram the ignition key. If the
vehicle starts and runs as deigned after disconnecting the system he can fully
remove the system or leave it in place but disabled. It’s up to you whether to remove it
completely or leave components dangling.
Also, if the remote start
system is the cause of the trouble you might consider returning to the shop
that installed it. They may be able to
repair it. Then your truck will be as
warm as toast before you enter the cabin.
Wait For Computers To Fall
Asleep
Question 6I have a 2000 Toyota Avalon with two problems. Once in a while when I start the engine the starter stays engaged and won’t release. When this happens I turn off the ignition and restart. The starter returns to normal and does not stick. The other problem is the battery dies after the car is parked for a few days. I need to jump it. A new battery was installed about two years ago.
I went to a repair shop and
the starter did not act up for them.
They tested the battery and said it is marginal and should be
replaced. They also found that there is
a high draw on the battery after the ignition is turned off. They say the cause of the issue is the
display in the center of the dash. They
told me it is normal for there to be some electrical activity after turning off
the ignition but it is too high. They
want to replace the battery and dash display.
Does this make sense to you?
B.A., email
Answer 6
Since the starter sticks you
might consider replacing it. Also, since
the battery is weak and it is two years old there is reason to replace it. It might be covered under a prorated warranty
that will drop the cost of a new battery.
As for replacing the dash
display, it is normal for computers to draw power from the battery for a while
after the ignition is shut off. Some
computers remain active for an hour or so.
Since the dash display is a computer and other than the electrical draw
it is operating normally providing information to you and full function, your
shop might consider testing for an electrical draw after the car has been off
for more than an hour. They may find the
dash unit has gone to sleep and no longer draws above average milliamps of
power from the battery. If so, there is
no need to replace it.
Thank you for all the 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@hotmail.com. 01/20/2014 ® DR. GIZMO © 1989 - Present
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