Denso 3313 Spark Plug

Denso 3313 U-Groove Spark Plug Overview

The Denso 3313 spark plug is a conventional secondary ignition component built around a U-Groove ground electrode design for improved ignitability and more efficient combustion. It uses a copper core center electrode, nickel tip materials, and a 5000-ohm resistor to support stable spark delivery in the correct application.

For drivers searching for a Denso spark plug for Honda Civic or other compatible vehicle applications, part number 3313 is part of Denso’s U-Groove Conventional line. This line focuses on dependable ignition performance with OE-style construction and a precise 0.9 pre-gap.

Key Features

• U-Groove ground electrode tip design for improved spark exposure
• 5000-ohm resistor for controlled electrical resistance
• Copper core center electrode for efficient heat transfer
• Nickel center and ground electrode tip materials
• Standard ground configuration with one ground electrode
• Flat seat design, 12.00 mm thread diameter, and 19.00 mm reach
• Manufacturer heat range 27 and 16.0 mm hex size

U-Groove Conventional Line Details

Denso’s U-Groove Conventional spark plug line is built for straightforward OE-style replacement service. The U-shaped ground electrode helps expose the spark kernel more effectively, which supports cleaner ignition in the specified engine application. If you are replacing a worn Denso 3313 plug in a Honda Civic or similar fitment, this design keeps the focus on consistent combustion and factory-style serviceability.

This part cross-references DENSO Auto Parts (e.g., XU27EPR-U) for the same application.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent ignition
• Misfire conditions related to degraded secondary ignition performance
• Reduced fuel efficiency from incomplete combustion
• Loss of throttle response from aged spark plug electrodes

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range against the vehicle service specification before installation. The Denso 3313 uses a flat seat, 12.00 mm thread diameter, 19.00 mm reach, and 0.9 pre-gap, so correct application matching is important for proper combustion chamber sealing and ignition performance. For Honda Civic spark plug replacement searches, confirm the engine-specific requirement before ordering.

Use proper spark plug handling practices during installation, including checking the gap condition and tightening to the manufacturer’s torque specification for the vehicle. Inspect ignition wires or coil-on-plug components at the same time if the plug is being replaced due to drivability concerns.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional ignition line, using nickel and copper-core construction for consistent service in the intended application. Part number 3313 is engineered to match the listed specifications and interchange reference for OE-style replacement use.