Engine Tune-Up

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Engine Tune-Up
By Jonathan Rollins
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• Tune Up Procedures are done as part of a
  routine maintenance rather than to correct a
  drivability problem.

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Wear safety glasses!
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Spark plug replacement

• Most new engines do not require spark plug
  replacement for up to (100,000 miles)

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Normal service and replacement items in a minor
tune-up are

• Perform a visual inspection for obvious problems
• Check for trouble codes on computer controlled
  vehicles
• Replace spark plugs
• Service the ignition system, including checking
  secondary components
• Replacing the air and fuel filter
• Changing oil and lubricating the chassis
• Testing and servicing emission control system,
  and resetting the reminder circuit
• Adjusting the fuel system if applicable
• Cleaning the throttle body and idle air bypass on
  fuel injected engines
• Road testing before and after tune-up to check
  engine performance

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Service and replacement items in a major tune-up
are

• Perform a scope analysis of engine system
• Testing and replacing spark plug wires
• Testing and replacing fuel pump
• Replacing drive belts
• Replacing brake, transmission, and other fluids
• Replacing or rebuilding the throttle body
• Rebuilding or replacing the distributer
• Adjusting the valve train (some engines)
• Replacing weak sensors oxygen sensor, cam
  position sensor, crank shaft position sensor, ect

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Six of the diagnostic tools used during a tune-up
are

• scan tool, an exhaust gas analyzer, a compression
  gauge, a multi meter, an oscilloscope, a vacuum
  gauge, and other tools

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Some performance factors affected by a tune-up
are

• Engine power acceleration
• Fuel consumption
• Exhaust emissions
• Smoothness of engine operation
• Ease of starting
• Engine service life

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General Tune-Up Rules

• It is important to gather engine and vehicle
  performance info before performing the tune-up
  because this gives you clues on what you need to
  investigate or replace.

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• It is important to bring the engine up to full
  operating temperature prior to diagnosing an
  operating condition because when the engine is
  cold you cannot obtain accurate test results.

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• Its important to maintain a vehicles service
  records because if a problem occurs you can check
  your record to correct the trouble.

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Tune-up safety rules

• It is important for the battery to be
  disconnected before maintenance so it does not
  accidentally crank the engine or electrical fire.

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Tune-up safety rules to follow

• Wear eye protection
• Set parking break
• Place vent hose on exhaust pipe
• Disconnect battery

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Typical tune-up procedures

• Battery problems-dirty case top, corroded
  terminals, and physical damage
• Air cleaner problems clogged or contaminated
  filter, inoperative air flaps or disconnected
  vacuum hoses.
• Belt problems- looseness, fraying, and slippage.
• Low fluid levels- engine oil, brake fluid, power
  steering fluid, ect.
• Deteriorated hoses- hardened or softened cooling
  system, fuel system, and vacuum hoses.
• Poor electrical connections-loose or corroded
  connections frayed, pinched, or burned wiring
  and terminals.

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Three important steps in replacing spark-plug
wires are

• To remove the spark-plug, first check that the
  spark-plug wires are numbered or located
  correctly in their clips. Grasping the spark-plug
  wire boot, pull the wire off the plug. Twist the
  boot back and forth if it sticks Ignition coils
  must be numbered before plugs can or located
  correctly in their clips. grasping the spark-plug
  wire boot, pull the wire off the plug. Twist the
  boot back and forth if it sticks. Ignition coils
  must be removed before plugs can be replaced. Be
  sure engine is cool before removing spark-plugs.
  Removing a spark-plug from a warm aluminum head
  can damage the threads in the spark-plugs holes.

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Tools used to remove spark-plugs

• Swivel ratchet, an extension, and a spark plug
  socket.

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The correct colors for the tip and insulator

• Grayish or brown properly burning
• Black or wet not firing or engine problem

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• If the spark-plug wire is not put on the right
  cylinder spark-plug, the plug will not fire.

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Oxygen sensors

• One and two wires need to be replaced at
  50,000-60,000 miles
• Heated three-wire oxygen sensors should be
  replaced at about 100,000 miles

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Recommended procedures for replacing a sensor

• Disconnect the negative battery cable. then,
  separate the sensor from the wiring harness by
  unplugging the connector. Never pull on the wires
  them selves, as damage may result.

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Three primary adjustments performance during a
tune-up

• Pick up coil air gap adjustment
• Idle speed adjustment
• Ignition timing adjustment

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Diesel engine tune-up

• Diesel engines require periodic maintenance
  similar to gasoline engines but dont have spark
  plugs to replace or an ignition system.

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Typical service tasks performed during diesel
engine maintenance intervals are

• Replacing the air filter element
• Cleaning, draining, or replacing the fuel filters
• Adjusting engine idle speed
• Adjusting accelerator and governor linkage
• Inspecting the engine and related systems
• Adjusting valve and injector timing
• Changing engine oil and oil filter
• Servicing emission control systems
• maintenance intervals are specific periods ( in
  miles or months ) for component service.