Denso 3129 Spark Plug

Reliable Ignition Performance for Geo and Toyota Vehicles

The Denso 3129 spark plug is engineered to deliver consistent ignition performance for select Geo and Toyota models, including the 4Runner, Celica, Corolla, Pickup, and Prizm. Designed with precision materials and specifications, this spark plug supports efficient combustion and engine reliability.

• U-groove ground electrode tip design for improved spark exposure
• Nickel ground and center electrode tips with copper core for durability and conductivity
• Standard ground configuration with a single ground electrode
• Flat seat type with 14mm thread diameter and 19mm reach for proper fitment
• Pre-gap size of 0.8 mm optimized for ignition efficiency
• Hex size of 16.0 mm for standard installation tools
• Manufacturer heat range of 16 suitable for specified vehicle applications

About the U-Groove Conventional Spark Plug 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 stable ignition and improved combustion efficiency. The conventional construction with nickel and copper materials balances durability and electrical conductivity, making it suitable for a range of Geo and Toyota vehicles requiring reliable secondary ignition components.

Technical Details and Specifications

This spark plug (part number 3129) incorporates a nickel ground electrode tip and a copper core center electrode with a nickel tip, providing a balance of wear resistance and thermal conductivity. The single ground electrode with a U-groove design increases the spark area, which can contribute to more complete combustion. The flat seat and 14mm thread diameter ensure compatibility with the specified Geo and Toyota models. The 0.8 mm pre-gap size is factory set to optimize ignition timing and performance.

Applications and Problem Solving

• Compatible with Geo 4Runner, Celica, Corolla, Pickup, and Prizm models
• Addresses misfires caused by worn or damaged spark plugs
• Helps improve cold start performance and throttle response
• Reduces fouling and carbon buildup with proper electrode design
• Supports consistent engine idling and fuel efficiency

Installation Notes and Tips

• Verify compatibility with your vehicle’s make and model before installation
• Use a 16 mm socket wrench for proper tightening
• Check and adjust spark plug gap if necessary, though pre-gap is factory set at 0.8 mm
• Apply anti-seize compound on threads if recommended by the vehicle manufacturer
• Torque to manufacturer specifications to avoid damage or improper sealing

Quality Assurance and Warranty

Denso spark plugs, including part number 3129, are manufactured to meet strict quality standards for ignition components. The materials and design undergo rigorous testing to ensure durability and performance in secondary ignition systems. Warranty coverage details should be confirmed with the original equipment manufacturer or authorized distributor.