Denso 4091 Spark Plug

Reliable Ignition with Denso U-Groove Conventional Spark Plug 4091

The Denso U-Groove Conventional Spark Plug 4091 is engineered to deliver consistent ignition performance for a variety of vehicles. Designed with a U-groove ground electrode tip and durable materials, this spark plug supports efficient combustion and reliable engine operation.

• U-groove ground electrode tip design for improved spark exposure
• Nickel ground electrode core and tip for durability
• Copper center electrode core for optimal conductivity
• Standard ground configuration with a single ground electrode
• Flat seat type with 19.00 mm reach and 12.00 mm thread diameter
• Pre-gap size of 0.7 mm for precise ignition timing
• Hex size of 18.0 mm for standard installation tools
• Manufacturer heat range of 22 suitable for moderate engine temperatures

About the U-Groove Conventional Product Line

The Denso U-Groove Conventional spark plug line features a unique U-groove ground electrode tip design that enhances spark exposure to the air-fuel mixture. This design supports more efficient combustion compared to traditional flat electrodes. The conventional construction uses nickel and copper materials to balance durability and conductivity, making it suitable for a wide range of gasoline engines requiring reliable secondary ignition components.

Technical Details and Performance

The Denso 4091 spark plug incorporates a copper core center electrode with a nickel tip, providing excellent electrical conductivity and resistance to wear. The single nickel ground electrode with a U-groove tip improves spark efficiency by increasing the spark area. With a pre-gap size of 0.7 mm and a flat seat, this spark plug ensures consistent ignition timing and proper sealing in the combustion chamber. The 19.00 mm reach and 12.00 mm thread diameter make it compatible with many vehicle engines requiring these specifications.

Common Applications and Problem Solving

• Restores engine misfire issues caused by worn or fouled spark plugs
• Improves cold start performance in compatible vehicles
• Reduces rough idling and hesitation during acceleration
• Helps maintain fuel efficiency by ensuring proper combustion
• Prevents spark plug fouling in moderate heat range engines

Installation Notes and Tips

When installing the Denso 4091 spark plug, ensure the pre-gap of 0.7 mm is maintained or adjusted according to the vehicle manufacturer’s specifications. Use an 18 mm socket wrench for proper tightening to avoid damage to the spark plug or cylinder head. Confirm compatibility with your vehicle’s engine specifications, particularly thread diameter and reach, to ensure proper fitment and sealing.

Quality Assurance and Warranty

Denso spark plugs are manufactured to meet strict quality standards for durability and performance. The 4091 spark plug undergoes rigorous testing to ensure consistent ignition and resistance to electrode wear. While specific warranty details are not provided, Denso products typically come with manufacturer-backed quality assurance to support reliable operation in compatible vehicles.