01/01/2018
“Dr. Gizmo”
By Phil Arendt
Question
1
I
have 2000 Chevrolet Silverado 1500 with a 5.3-liter V-8 engine that sometimes
starts hard. Normally, the engine starts
within the first two revolutions. When
it does not start right away it cranks for about six or seven seconds before I
shut off the key. If it cranks longer
the cranking slows down and I have to shut off the key. When I try to start again it starts right
up.
I
have been to two different shops for this trouble. They have done several tests on the spark
plugs and fuel injectors but did not find anything wrong.
One
shop suggested replacing the fuel pump even though it passed tests. I told them to go ahead so they replaced the
fuel pump, fuel filter and regulator. This
made no difference.
My
truck has 197,000 miles. I’ve owned it
since it was new. This is the only
trouble I have ever had with it. Have
you ever heard something like this?
M.T., email
Answer
1
Every
day in this business brings on new challenges.
Your truck is no exception. The
one clue that stands out the most is your description of the engine revolutions
slowing down while cranking. Sometimes a
technician will overlook a clue such as this because he or she is looking for
another issue that might be complex in nature.
The condition you experience might be due to low voltage. A battery cable might be loose. Maybe the battery no longer holds a full
charge and needs replacement. Just maybe
a battery cable connection is suffering from corrosion.
It’s
time for a technician too look for a basic cause for the condition.
Question
2
The
parking and dash lights quit in my 1999 Toyota Celica GT. I checked the all the fuses. All of them are good. I also checked if power is at the fuses for
the dash and parking lights. There is
power. I then used a jumper wire to
apply power to both sets of lights. They
work.
Is
this caused by a broken wire or is there something else I should look for? R.K., email
Answer
2
It
would be helpful if you utilized a wiring schematic. Be this as it may the trouble might be caused
by a faulty relay or perhaps a broken or corroded ground connection. You will find relays for the lights in the
fuse panels. Since it appears you have
equipment to test circuits, you should be able to test the relays and ground
connections.
What
needs repair all depends upon what you find.
The cure might be as simple as a thorough cleaning of a ground
connection.
Question
3
I
have a 2010 Chevrolet Equinox LS with a 2.4-liter engine that quit while
driving a steady speed on the highway.
It has 162,000 miles. No warning
lights came on when it shut off. It shut
off as if I turned off the ignition. It
was towed to a reliable shop.
After
tests and some disassembly my shop said the timing chain jumped. They said that this is an interference engine
and it might be shot. They said that the
valves and pistons smashed together.
They say this causes broken pistons and valves. They won’t know for sure how much damage
there is until they disassemble it. They
suggested installing a rebuilt engine instead of tearing this one apart to
inspect the damage.
I
did not hear any metallic sounds when the engine stopped. Is what they are saying right? Can this engine be saved? Is it better just to replace it? D.V., email
Answer
3
What
happened might have caused severe damage to the pistons but maybe not. Sometimes when this happens the only damage
is to the cylinder head. Consider asking
a technician just to remove the cylinder head for inspection. He might find bent valves and certainly
debris from the timing chain. The
pistons might have gone through this incident without damage. If so the engine does not need
replacing. A technician can install a
new cylinder head and timing chain and all should be well.
Question
4
When
I start the 7.3-liter engine in my 2001 Ford Excursion Limited with 288,000
miles it smokes like crazy and runs rough.
This began shortly after a vacuum pump was replaced.
Once
the engine warms up it runs fine. Does this
have anything to do with the vacuum repair?
If not what do you think is wrong?
R.P. email
Answer
4
It’s
not likely your diesel is suffering from this condition due to previous repairs
for the vacuum pump. More than likely
the issue is caused by a fuel system problem such as contaminated fuel or
perhaps failed glow plugs. It appears
the engine is spewing unburned fuel.
It’s
time to visit a repair shop that specializes in diesel engine repairs. Tests will find the cause. Consider leaving the vehicle overnight so a
technician can experience the trouble when the engine is stone cold in the
morning.
Question
5
The
battery in my 2004 Volkswagen Touareg with a 4.2-liter motor dies
overnight. My car has 151,000
miles. The battery is only six months
old so I doubt it is the problem. I have
checked all the fuses. They look
fine. I also have checked removed the
battery cables to clean them. They are
now clean and tight. Over the weekend I
charged the battery all day but the next day it was dead. Everything is turned off. Do you think the alternator generator is the
cause of the trouble? D.N., email
Answer
5
While
the battery is only six months old it might be defective. It should be tested. It might need replacement. It’s also possible it is suffering from
excessive parasitic discharge. Although
all switches are turned off there might be an issue such as a stuck relay,
failed computer module or another issue draws power from the battery. While it is possible a fault in the
alternator causes the condition it would not be wise to replace it until tests
show it has a fault.
Consider
a trip to an experienced technician who will perform tests and determine the
cause. Repair might be as simple as
replacing a relay.
Question
6
My 1993 Cadillac DeVille failed to start. It
did absolutely nothing when I turned the key.
The dash lights came on and that was it.
I had it towed to a shop that has been servicing it for many years. Of course after the tow truck arrived at the
shop the car started without any problem and was driven off the flatbed truck.
My
shop restarted it without any trouble several times during the day. The only thing they found is that the
security light flashes after it starts.
They say there must be something wrong with the security system but
tests have not found any problems. Do
you have any suggestions? H.L., email
Answer
6
This
is an interesting problem. Tests did not
find any issues but it appears your technician is on the right path. There does indeed seem to be an issue with
the antitheft system.
It’s
likely your technician performed diagnostic test that checked modules. No problems were found. It’s time for him or her to look for other
possible causes. One place to look is at
the steering column. There is a key
resistor and related conductors. It’s
possible a conductor has a small break that intermittently opens the
circuit. This will prevent starts.
If
indeed a technician finds this is the trouble it’s likely he will suggest a
couple different repair options for you to consider.
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
his e-mail address drgizmo@drgizmo.ws. 01/01/2018 ® DR. GIZMO © 1989 – Present
