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.
2007 Mazda 6 L4-2.3LFACTORY OEM SERVICE PROCEDURE
Spark Plug: Testing and Inspection
SPARK PLUG INSPECTION[L3, AJ]
Plug Gap Inspection
CAUTION:
- To avoid possible damage to the tip, do not adjust the plug gap.
- To prevent damaging the tip, use a wire type plug gap gauge when inspecting the plug gap.
1. Measure the spark plug gap using a wire type plug gap gauge.
- If it exceeds the specification, replace the spark plug.
Standard plug gap
L3: 1.25-1.35 mm {0.05O-0.053 in}
AJ: 1.29-1.45 mm {0.051-0.057 in}
Cleaning
CAUTION:
- Carbon may adhere to the tip of the spark plug during vehicle delivery or repeated short distance driving during the winter time. If there is any malfunction such as rough idling or start difficulty due to carbon adhesion causing plug fouling, burn oft the carbon by performing no-load racing of the engine.
- When performing the no-load racing, apply the side brake and foot brake, move the shift lever to neutral (MTX), or the selector lever to P position (ATX) to prevent an accident and serious injury.
- To avoid possible damage to the spark plug tip, do not use a wire brush for cleaning.
NOTE:
- To avoid possible damage to the tip, use gasoline to clean the spark plugs after removing dirt.
- If the accelerator pedal is depressed continuously for a specified time, the engine speed may decrease to the idle speed. This is due to the fuel cut control operation, which prevents overheating, and it does not indicate a malfunction.
- Do not perform no-load racing at high engine speed continuously for 10 s or more.
1. If there is carbon adhering to the spark plug, perform no-load racing at 4,000 rpm for 2 mm, 2 times.
Visual inspection
1. Inspect the following items:
- If any of the following malfunctions are indicated, replace the spark plug.
- Insulator breakage
- Worn electrode
- Damaged gasket
- Badly burned insulator (sparking side)
Resistance Inspection
1. Measure the resistance of the spark plug using a tester as shown in the figure.
- If not within the specification, replace the spark plug.
Resistance
L3: 3.0-7.5 kilohms [25 °C {77 °F}]
AJ: 8.0-20 kilohms [25 °C {77 °F}]
Plug Gap Inspection
CAUTION:
- To avoid possible damage to the tip, do not adjust the plug gap.
- To prevent damaging the tip, use a wire type plug gap gauge when inspecting the plug gap.
1. Measure the spark plug gap using a wire type plug gap gauge.
- If it exceeds the specification, replace the spark plug.
Standard plug gap
L3: 1.25-1.35 mm {0.05O-0.053 in}
AJ: 1.29-1.45 mm {0.051-0.057 in}
Cleaning
CAUTION:
- Carbon may adhere to the tip of the spark plug during vehicle delivery or repeated short distance driving during the winter time. If there is any malfunction such as rough idling or start difficulty due to carbon adhesion causing plug fouling, burn oft the carbon by performing no-load racing of the engine.
- When performing the no-load racing, apply the side brake and foot brake, move the shift lever to neutral (MTX), or the selector lever to P position (ATX) to prevent an accident and serious injury.
- To avoid possible damage to the spark plug tip, do not use a wire brush for cleaning.
NOTE:
- To avoid possible damage to the tip, use gasoline to clean the spark plugs after removing dirt.
- If the accelerator pedal is depressed continuously for a specified time, the engine speed may decrease to the idle speed. This is due to the fuel cut control operation, which prevents overheating, and it does not indicate a malfunction.
- Do not perform no-load racing at high engine speed continuously for 10 s or more.
1. If there is carbon adhering to the spark plug, perform no-load racing at 4,000 rpm for 2 mm, 2 times.
Visual inspection
1. Inspect the following items:
- If any of the following malfunctions are indicated, replace the spark plug.
- Insulator breakage
- Worn electrode
- Damaged gasket
- Badly burned insulator (sparking side)
Resistance Inspection
1. Measure the resistance of the spark plug using a tester as shown in the figure.
- If not within the specification, replace the spark plug.
Resistance
L3: 3.0-7.5 kilohms [25 °C {77 °F}]
AJ: 8.0-20 kilohms [25 °C {77 °F}]
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:
- • 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.
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