Bosch 9691 Spark Plug

Bosch OE Fine Wire Double Iridium Spark Plug

Bosch 9691 is an OE Fine Wire Double Iridium spark plug built for direct ignition performance and extended service life. It uses an ultra-fine wire center electrode, a laser-welded tapered ground electrode, and a preset gap for precise ignition in modern engines.

This Bosch OE Fine Wire Double Iridium line focuses on OE-style fit and stable spark delivery for vehicles such as the Hyundai Elantra, Hyundai Ioniq, Kia Niro, Smart Fortwo, and Mitsubishi Outlander. Part number 9691 is engineered for applications that call for a flat seat, 12 mm thread diameter, 26.5 mm reach, and a 16 mm hex.

Key Features

• Double iridium construction for strong ignitability and long service life
• Fine-wire center electrode with iridium-alloy firing pin
• Laser-welded ground electrode with iridium alloy inlay
• Preset .7 gap; do not gap before installation where OE notes specify preset gap
• Resistor design with 6000 resistance rating
• Ceramic insulator and non-projected insulator type
• Flat seat design for listed OE applications

Detailed Description

Bosch 9691 is part of the OE Fine Wire Double Iridium product line, developed for drivers and technicians who need an OE-style spark plug with durable electrode materials and consistent ignition performance. The fine-wire design helps concentrate spark energy, while the laser-welded tapered ground electrode supports stable firing under demanding combustion conditions. The iridium center electrode and iridium-alloy ground inlay are selected to maintain performance over extended service intervals.

Compatible With 2021-2025 Hyundai Elantra, N/A; 2021-2022 Hyundai Ioniq, N/A; 2021-2022 Kia Niro, N/A; 2017-2020 Hyundai Ioniq, N/A; 2017-2020 Kia Niro, N/A; 2008-2015 Smart Fortwo, N/A; and 2007-2013 Mitsubishi Outlander, N/A. This part cross-references no listed aftermarket numbers in the provided data.

What It Helps Address

• Hard starting caused by worn spark plug electrodes
• Misfire concerns related to weak or inconsistent spark
• Rough idle from degraded ignition performance
• Loss of throttle response from aged plugs
• Service intervals that call for a long-life iridium plug

Installation Notes and Tips

Verify engine application before installation and match the listed OE-style specifications, including thread diameter, reach, seat type, and heat range. The gap is preset, so do not adjust it unless the vehicle service information specifically calls for verification. Use proper spark plug service procedures and torque specifications for the engine.

Quality Assurance

Bosch OE Fine Wire Double Iridium plugs are built with iridium and platinum-iridium electrode materials, laser-welded construction, and OE-focused dimensions for consistent fitment in the listed applications. Part number 9691 is designed to meet the requirements of the vehicles shown above.