Denso 4709 Spark Plug

Denso Iridium TT Spark Plug 4709

The Denso Iridium TT 4709 spark plug combines OE-style durability with a performance-focused electrode design for steady ignition and responsive engine operation. It is built for a wide range of import and domestic applications, including Honda Accord, Mitsubishi Eclipse, and Volkswagen Golf fitments.

Key Features

• Iridium center electrode tip for consistent spark delivery
• Platinum twin-tip ground electrode design for stable ignition performance
• Copper core center electrode and nickel ground electrode core for efficient heat transfer
• 5000 ohm resistor for reduced electrical noise
• 1.0 mm pre-gap for direct replacement service
• Flat seat, 14.00 mm thread diameter, and 19.00 mm reach
• Manufacturer heat range 20

Iridium TT Product Line

Denso Iridium TT plugs are part of the Iridium TT line, which pairs an iridium center tip with a twin-tip ground electrode layout. This construction is used to balance long service life with strong ignition performance, making the Denso 4709 a practical choice for drivers maintaining older import vehicles and classic applications.

Detailed Description

Denso 4709 is a spark plug for secondary ignition systems that uses an iridium center electrode tip and a platinum twin-tip ground design to promote reliable spark formation. The copper core center electrode helps manage heat, while the nickel ground electrode core supports durability in everyday driving. With OE-style dimensions and a flat seat design, this plug is a direct-service option for many vehicles that call for the Iridium TT specification. This part cross-references DENSO Auto Parts IW20TT for the same application.

Compatible fitment includes 1987-1987 Honda Accord, 1983-1987 Honda Prelude, 1990-1992 Volkswagen Golf, 1990-1992 Volkswagen Jetta, 1989-1993 Mitsubishi Galant, and 1990-1999 Mitsubishi Eclipse. It also covers many additional applications such as 1985-1993 Volkswagen Cabriolet, 1985-1992 Mitsubishi Mirage, and 1979-1988 Saab 900.

What It Helps Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition output
• Misfire symptoms related to aged secondary ignition components
• Reduced throttle response from degraded spark quality
• Maintenance replacement for OE-style spark plug service intervals

Installation Notes and Tips

Verify the thread diameter, reach, seat type, and heat range against the vehicle specification before installation. Check the pre-gap setting during service and confirm the ignition system is in good condition, including wires, coils, and distributor components where equipped. For fitment-specific service, use the vehicle listing for the exact year and model, such as Honda Accord, Mitsubishi Eclipse, or Volkswagen Golf applications.

Quality Assurance

Denso manufactures this spark plug to OE-style dimensional standards with performance-oriented electrode materials for dependable service in a broad range of import and domestic engines. The Iridium TT design is built to support consistent ignition performance and long-term durability in the applications listed.