Denso 4090 Spark Plug

Denso 4090 U-Groove Spark Plug

The Denso 4090 spark plug is a conventional ignition component built around a U-Groove ground electrode for improved ignitability and more consistent combustion. It is a practical choice for drivers searching for a Denso spark plug 4090 replacement with copper and nickel electrode construction.

Key Features

• U-Groove ground electrode tip design for stronger spark exposure
• Nickel ground electrode tip with a standard ground configuration
• Copper center electrode core for dependable conductivity
• Nickel center electrode tip for conventional ignition service
• Pre-gapped to 0.7 mm for straightforward installation
• Flat seat design, 12.00 mm thread diameter, 19.00 mm reach, and 18.0 mm hex size
• Manufacturer heat range 22

Product Details

Denso U-Groove Conventional spark plugs are built for drivers who want a straightforward secondary ignition service part with OE-style construction. The U-shaped ground electrode helps expose the spark kernel more effectively, which supports cleaner ignition events and stable engine operation. Part number 4090 is also referenced as DENSO Auto Parts X22ES-U, making it easier to match the correct Denso 4090 spark plug when searching by cross-reference.

For fitment-based searches, this spark plug is commonly researched for Denso spark plug 4090 applications and Denso U-Groove Conventional ignition service. It is a direct replacement-style part for vehicles that specify the listed thread, reach, seat, and heat range requirements. This part cross-references DENSO Auto Parts X22ES-U for the same application.

Common Issues It Can Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent spark delivery
• Misfire symptoms related to degraded ignition performance
• Reduced fuel efficiency from incomplete combustion
• Loss of throttle response from aged secondary ignition components

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range against the vehicle service specification before installation. The pre-gap size is 0.7 mm, so confirm the engine calls for that gap setting before use. Clean the plug seat area, thread the plug by hand first, and tighten to the manufacturer’s torque specification to protect the cylinder head and ensure proper sealing.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional line, which focuses on conventional ignition service with a U-groove electrode profile and OE-style material selection. For shoppers comparing Denso 4090 and X22ES-U references, this part provides a consistent specification match for the listed application requirements.