Denso 4509 Spark Plug

Denso Platinum TT Spark Plug 4509

Denso Platinum TT 4509 is a spark plug built for secondary ignition service across a wide range of classic Ford, Chevrolet, GMC, Dodge, Jeep, and GM applications. Its twin-tip design promotes faster flame travel for more complete combustion, while the platinum center electrode supports consistent ignition performance.

Key Features

• Twin-Tip ground electrode design for quicker flame propagation
• Platinum center electrode tip for stable spark delivery
• Copper core center electrode for efficient heat transfer
• Nickel ground electrode core material
• 5000 ohm resistance
• Tapered seat design
• 14.00 mm thread diameter, 11.60 mm reach, 16.0 mm hex size
• Pre-gapped at 1.0 mm

Product Details

The Denso Platinum TT line focuses on controlled combustion and dependable ignition response. This plug uses a Titanium Enhanced Twin-Tip ground electrode configuration to help the spark kernel develop quickly, which supports smoother combustion in engines that call for a tapered-seat spark plug with these dimensions. The part number 4509 is a direct reference point for shoppers searching Denso 4509 spark plug, Denso Platinum TT 4509, or OE-style ignition service parts for older Ford F-150, Ford Mustang, and Chevrolet Camaro applications.

This part cross-references DENSO Auto Parts PTF16TT for the same application.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent spark output
• Misfire conditions tied to degraded secondary ignition components
• Reduced combustion efficiency in high-mileage engines
• Maintenance replacement for vehicles calling for a tapered-seat platinum plug

Installation Notes and Fitment

Verify thread diameter, reach, seat type, and heat range before installation. The plug is listed with a 14.00 mm thread diameter, 11.60 mm reach, 16.0 mm hex size, tapered seat, and manufacturer heat range 16. Compatible With 1978-1997 Ford F-350, 1990-1996 Ford Bronco, 1990-1996 Ford E-150 Econoline, 1990-1996 Ford E-150 Econoline Club Wagon, 1978-1996 Ford E-350 Econoline, 1990-1996 Ford F-150, 1978-1996 Ford F-250, and 1987-1995 Ford Mustang. Additional fitment includes 1978-1992 Chevrolet Camaro, 1988-1993 Chevrolet C1500, 1988-1993 Chevrolet K1500, 1978-1987 Buick Regal, and 1984-1986 Jeep Cherokee. For fitment-specific searches, use Denso 4509 spark plug for Ford Mustang, Chevrolet Camaro, or Ford F-150 secondary ignition service.

Quality Assurance

Denso Platinum TT spark plugs are engineered around a platinum-tipped center electrode and twin-tip ground design for consistent ignition service. The 5000 ohm resistor helps control electrical noise in the ignition system, and the pre-set gap supports straightforward installation when the application matches the listed specifications.