Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSTOYOTA2004CELICA GT, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 375 (IGNITION SYSTEM)IGNITION SYSTEM (3MZ-FE)INSPECTION

2004 Toyota Celica GT, Standard

Ignition System (3MZ-FE): Inspection

2004 Toyota Celica GT, StandardSECTION Inspection

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT SPARK PLUG
NOTE:
- Do not use a wire brush to clean the spark plug.
- Do not try to adjust the electrode gap of a used spark plug.
1. Inspect the resistance.
  1. Using an ohmmeter, measure the resistance between the insulation and body ground.
    Resistance: 10 MΩ or more
    
    If the resistance is not as specified, check the electrode gap.
    
    Fig 1: Measuring Resistance Between Insulation And Body Ground
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Alternative inspection method.
  1. Quickly accelerate the engine speed to 4,000 rpm 5 times.
  2. Remove the spark plug.
  3. Visually check the spark plug.
  4. If the electrode is dry...OK.
  5. If the electrode is wet...Proceed to step (c).
  6. Reinstall the spark plug.
    
    Fig 2: Checking Spark Plug Electrode
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check the appearance.
  1. Check the thread and insulator of the spark plug for damage.
    If damaged, replace the spark plug.
    
    Recommended spark plug:
    
    Fig 3: Identifying Spark Plug
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

RENDER: 1.0x

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When to See a Mechanic

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

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