Walker 921-2025 Ignition Coil

Walker ThunderSpark Ignition Coil

Walker ThunderSpark ignition coil Part Number 921-2025 is a direct-fit ignition component for select BMW applications. It supports consistent spark delivery for BMW 540i, X5, Z8, 320i, 325i, 325xi, 525i, Z3, 323ti, 328Ci, 740i, 740iL, 750iL, 850Ci, 840Ci, 528i, and M3 models listed below.

Key Features

• Walker ThunderSpark product line ignition coil
• Part Number: 921-2025
• Fits select BMW models with Bosch system or square coil spark plug wire set applications
• Application-specific fitment for listed BMW engines and model years
• Direct replacement ignition coil for maintenance and repair work

Fitment Details

• Fits 1997-2003 BMW 540i, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 2000-2003 BMW X5, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 2002-2003 BMW Z8, N/A, ThunderSpark
• Fits 2002 BMW 320i, N/A, To 09/2002, w/ Bosch System; Single Coil
• Fits 2001-2002 BMW 325i, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 2001-2002 BMW 325xi, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 2001-2002 BMW 525i, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 2002 BMW Z3, N/A, w/ Bosch System; Single Coil
• Fits 2001 BMW 320i, N/A, w/ Bosch System; Single Coil
• Fits 1997-2001 BMW 740i, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1996-2001 BMW 740iL, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1997-2001 BMW 750iL, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1999-2001 BMW Z3, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1999-2000 BMW 323ti, N/A, w/ Bosch Coil; Single Coil
• Fits 2000 BMW 328Ci, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1998-1999 BMW 850Ci, N/A, w/ Bosch System; Single Coil
• Fits 1996-1997 BMW 840Ci, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark
• Fits 1996 BMW 528i, N/A, w/ Bosch System; Single Coil
• Fits 1994-1995 BMW M3, N/A, Fitment: Square Coil Spark Plug Wire Set; ThunderSpark

What It Helps Address

• Engine misfire caused by a weak or failing ignition coil
• Hard starting related to inconsistent spark output
• Rough idle from degraded ignition performance
• Loss of power under load from ignition breakdown
• Check engine light conditions tied to ignition coil faults

Installation Notes

Verify the vehicle’s ignition system style before ordering, since this part is listed for both Bosch system single-coil applications and square coil spark plug wire set applications. Confirm the BMW model, year, and engine configuration against the fitment table before installation. Part Number 921-2025 should be matched to the exact application shown for BMW 540i, X5, Z8, 320i, and other listed models.

Quality Assurance

Walker ThunderSpark is the product line identified for this ignition coil, and the listed fitment is application-specific for the BMW models shown. This part cross-references no additional part numbers in the provided data.