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Car Back Fire Questions and Answers
This category contains featured questions as examples. They relate to most vehicles.
Question: 2002 Ford F150
mileage: 90,000. I am one of those guys that
really enjoys taking care of his truck, it
stays in a garage at night, I keep up on all
the services, etc. I was on my way back from
visiting my brother in the valley, heading
up an on ramp to the freeway when it started
backfiring. I made it onto the freeway and
it seemed ok but now whenever I accelerate
the truck backfires?. I have installed a new
fuel filter thinking that is what it could
be... but no help. Thanks for the help in
advance.
Answer: There are two
main things that can cause this condition.
First is a low fuel pressure condition. Full
fuel pressure is needed under load, check
fuel pressure under load it should stay
between 35-45 pounds if not replace the fuel
pump. Second is the ignition system. If the
ignition system is worn it can misfire
causing the backfire you describe. Check
your spark plugs and ignition coils, replace
as needed.
Question: 1998 Jaguar
XK-8 miles: 76,000. Hi, I own a 1998 Jaguar
XK-8 it has been a great car for years but
now when I take my car out first thing in
the morning it runs rough, seems low on
power and sometimes backfires. When it warms
up it seems ok. I have had all regular
service work done at the dealer so I took it
in. They charged me $122.00 to tell me they
didn't know what was wrong. They scanned the
computer but it didn't show anything and
they couldn't get the car to duplicate it.
What do I do now?
Answer: This is a
difficult problem to detect because the
computer can not sense a malfunction, the
vehicles computer system thinks everything
is ok. In reality what is happening is the
electrical component inside the
MAF sensor becomes contaminated by
air impurities. These containments imbed
themselves to the electrical component that
senses the air flow causing the sensor to be
slightly off, but not enough to trigger the
MIL (malfunction indicator lamp). Replace
the
MAF sensor with a new. NOTE: (Mass
Air Flow MAF sensor or Air Intake Sensor
AIS, depending on manufacturer. It does the
same thing only with different names).
New "How
to Repair Guides" -
Fuel Filter -
Oil Filter -
Air Filter -
Radiator -
Tune-Up
Question: 1994 Mazda
B3000 3.0 L V-6 mileage: 153,000.
I recently had a tune up done to the truck
and had the plugs, wires, rotor, and cap
changed. It was also discovered that the
thermostat was stuck open that was changed
too. Now, after the truck warms up there is
a low burping and repetitive backfire in the
exhaust system. The repair shop has no clue.
They say that there are no fault codes being
produced. A compression test was done and
the results were fine 155 to 150 lbs, except
for #3 and #6 at 147. The shop has test
drove the truck and knows that it is
happening but cannot give me any answers.
They say the have tested the injectors, O2
sensors, compression, and done multiple
computer diagnostics. The longer distances I
drive the truck the more repetitive the
backfire and louder. What could be a
possible solution?
Answer: Check the air
diverter valve and vacuum hoses. Check for
vacuum leaks and check the air injection
system.
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