2005 Mercury Montego Base, AWDFACTORY OEM SERVICE PROCEDURE

Engine Ignition

The electronic ignition (El) system for the 3.0L Duratec engine consists of the following components:

  • Crankshaft position (CKP) sensor
  • Camshaft position (CMP) sensor
  • 6 ignition coil-on-plugs
  • 6 spark plugs

The CKP sensor:

  • is a variable reluctance sensor.
  • is mounted in the front cover.
  • is triggered by a 36-minus-l tooth trigger wheel located behind the front cover.
  • provides base timing and crankshaft speed (rpm) to the powertrain control module (PCM). For additional information, refer to ELECTRONIC ENGINE CONTROLS .

The CMP sensor:

  • is a variable reluctance sensor.
  • is mounted in the front cover.
  • is triggered by the high point mark on the LH exhaust camshaft.
  • provides camshaft rotational location information to the PCM. For additional information, refer to ELECTRONIC ENGINE CONTROLS .

The 6 ignition coil-on-plugs:

  • are connected directly to each spark plug.
  • change low voltage signals from the PCM to high voltage pulses.
  • supply the high voltage pulses to the spark plugs.

The 6 spark plugs:

  • change high voltage pulses into a spark which ignites the fuel and air mixture.
  • originally equipped on the vehicle have a platinum-enhanced active electrode for long life.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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