We are a team of ASE certified mechanics that have created this guide to help
you save money while doing the job yourself, or at least see what you are paying
for when having the job done at a shop. An engine tune up is required between 35,000
to 75,000 miles depending on driving conditions and the vehicle's manufacturer
recommendations. This service comprises many individual operations which we have
listed below, this list can vary depending on engine ignition and fuel system designs.
When a tune up is performed there can be many variables which affect the parts
and labor price. Some shops consider just a spark plug replacement as a tune up
which by itself is incomplete, so it best to get a full list of what is included
with the service, an
engine oil change can be included as well. By looking under the hood you can see if the engine has coil over
spark plugs (COP) set up that uses no spark plug wires, this is one configuration
example which will cause price fluctuations. When purchasing tune up parts let it
be known there are quality variables that affect price and the performance of each
item. If exact times or procedures are needed you can ask
our experts to supply you with the information (free), or consult an online
resource such as AllData DIY (pay).
Let's Jump In!
Spark plugs are the most major part of a tune up which must be replaced
without fail. Before removing the spark plugs use compressed air to clear the
plug well free of dirt and debris which will help stop internal contamination
of the cylinders. Remove the ignition coil or plug wire from the spark plug,
if engine oil is present on the outside of the plug the
valve cover gaskets need replacement.
Most spark plug gaps are pre-set and ready to install but because of shipping
conditions the gap can become mal-adjusted, confirm the proper gap by using
a spark plug gap tool. Inspect the
new spark plug's porcelain for cracks and isolator condition before installing
(new spark plugs can be defective). If the ignition system uses plug wires,
replace the spark plugs and
wires one at a time to avoid confusion, mark the wires clearly while confirming
proper length of each wire, also twist the plug wire boot to help break the
seal which will assist in the wire removal.
After the ignition coil has been removed (COP systems), inspect the coil
for dark or light markings which indicates electrical leakage failure warranting
coil replacement, also inspect the coil low voltage electrical terminals for
corrosion or signs of heat which indicates failure.
An ignition system can be constructed with an distributor cap and rotor
which is responsible for distributing the ignition spark from the coil to the
individual cylinders, over time the electrical terminals can become burnt and
corroded and should be replaced as part of the tune up.
An engine processes large amounts of air while in operation, this will cause
the throttle actuator to get dirty, a condition called Coking, this is where
heavy air particles are left behind hindering the actuators performance. An
engine tune up should include a
throttle bore actuator cleaning
Manually controlled actuators use a throttle cable which utilizes an
idle air control valve
(IAC) to adjust engine idle speed via the
Much like the throttle bore actuator the IAC is subject to the Coking condition
as well and should be cleaned within the tune up service to ensure proper operation.
The engine air filter is used to help keep dirty and debris from entering
the engine, this too will become dirty which cases engine performance to suffer,
inspect and replace the
air filter as needed.
Some engines are equipped with a
mass air flow sensor
(MAF) which provides feedback information to the engine computer by monitoring
the amount of air that enters the engine. This is also subject to Coking which
contaminates the sensor wire located internally inside the sensor. Remove the
sensor and use MAF cleaner to alleviate the sensor wire (hot wire) from dirt
and air contaminants to help return the correct sensor operation.
Vehicles can be equipped with a
serviceable fuel filter
(not inside the fuel tank) which should be changed out during a tune up service.
This fuel filter is used to remove fuel impurities before being processed through
the fuel injectors allowing the fuel system to stay clean and trouble free.
This filter is optional and will vary per vehicle manufacturer.
Our certified technicians are ready to answer tune up
questions for free. We hope you saved money and learned from this guide. We
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