Full Engine Tune-Up

Complete engine tune-up including spark plug replacement, ignition coil inspection, throttle body cleaning, air filter replacement, and fuel system inspection for the 2009 Aston Martin DB9 6.0L V12.

Warnings

Tools required

Parts

• Spark plugs (NGK or OEM equivalent) × 12 — Use OEM specification - 12 required
• Engine air filter × 1 — Use OEM specification
• Cabin air filter × 1 — Use OEM specification
• Valve cover gaskets (if degraded) × 2 — Use OEM specification - 2 required

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely (minimum 2 hours after running)
3. Disconnect negative battery terminal and wait 10 minutes for system discharge
4. Remove engine cover by releasing quick-release fasteners or clips (typically 4 attachment points)
5. Photograph ignition coil arrangement and harness routing for reference during reassembly
6. Clear workspace around engine bay and organize storage for removed components

Procedure

1. 1

   Remove ignition coil covers and access panels
   Remove the plastic ignition coil covers from both valve covers. Verify the ignition coil cover fastener type and count against Aston Martin documentation (commonly Torx fasteners or push clips, but confirm before removal). The DB9 V12 uses a bank-specific layout, commonly 6 coils per side (12 total) — verify exact coil count and per-bank distribution against Aston Martin factory documentation before removal. Remove any decorative covers or cable routing clips that obstruct access to the coil packs. Use compressed air to clean debris from around coil wells before proceeding.
2. 2

   Disconnect and remove ignition coils - Bank 1 (passenger side)
   Disconnect the electrical connector from each ignition coil by pressing the release tab and pulling straight up. Remove the ignition coil mounting bolt from each coil pack using appropriate socket. Extract each coil by pulling straight up with steady pressure - they may be seated tightly in the spark plug wells. Inspect coil boots for cracks or carbon tracking and replace if damaged. Set coils aside in order. Note: The DB9 V12 uses coil-on-plug ignition with one coil per cylinder, 6 coils per bank (12 total). Verify the exact cover and coil arrangement against factory documentation before removal. Note: The DB9 V12 uses a bank-specific layout with 6 coils per cylinder bank, 12 coils total. Note: The DB9 V12 uses a coil-on-plug layout; verify exact coil count and per-bank distribution against factory service documentation before proceeding.
   Torque spec

   Ignition Coil Bolt8 Nm (6 lb-ft)
3. 3

   Disconnect and remove ignition coils - Bank 2 (driver side)
   Repeat the coil removal process for the driver side bank. Disconnect electrical connectors, remove mounting bolts, and extract all 6 coils. Inspect boots and coil bodies for damage, oil contamination, or carbon deposits. Oil in spark plug wells indicates valve cover gasket failure and should be addressed. Note: Disconnect and remove ignition coils - Bank 2 (opposite bank)
4. 4

   Remove spark plugs - Bank 1
   Use compressed air to thoroughly clean debris from each spark plug well before removal. Using the appropriate spark plug socket with extension, carefully remove all 6 spark plugs from Bank 1. Maintain gentle pressure and turn counterclockwise steadily. If resistance is encountered, do not force - apply penetrating oil and wait. Inspect removed plugs for wear patterns, gap condition, and electrode erosion. Abnormal wear indicates engine issues requiring further diagnosis. Note: If a spark plug binds during removal, stop immediately. Do not force it — apply penetrating oil, allow it to soak, and back the plug out in small increments to avoid stripping the aluminum threads.
   ⚠Aluminum cylinder heads are prone to thread damage. If a spark plug binds during removal, stop immediately and allow engine to heat slightly to aid removal through thermal expansion.
5. 5

   Remove spark plugs - Bank 2
   Clean spark plug wells with compressed air. Remove all 6 spark plugs from Bank 2 using the same careful technique. Inspect each plug and compare wear patterns between banks. Uneven wear between banks may indicate fuel delivery or ignition timing issues. Set all removed plugs aside for comparison with new plugs.
6. 6

   Inspect cylinder head threads and clean wells
   With all spark plugs removed, inspect the cylinder head threads in each well using a flashlight. Look for aluminum debris, carbon buildup, or damaged threads. Clean each well thoroughly with compressed air. If thread damage is suspected, use a thread chaser tool matching the factory spark plug thread size and pitch (verify against OEM specification) gently to clean threads - do NOT use a tap which removes material. Check for oil accumulation in wells indicating valve cover gasket seepage. Note: If thread damage is suspected, use a thread chaser tool matched to the factory-specified spark plug thread size and pitch (verify against Aston Martin documentation) gently to clean threads - do NOT use a tap which removes material. Note: If thread damage is suspected, use a thread chaser tool matching the OEM spark plug thread size and pitch (verify against factory documentation) gently to clean threads - do NOT use a tap which removes material.
7. 7

   Gap and prepare new spark plugs
   Verify the gap specification for your specific DB9 model year against Aston Martin factory documentation before installation; do not rely on an assumed value. Use a spark plug gap tool to verify each new plug is properly gapped - do not assume pre-gapped plugs are correct. Only apply anti-seize if specified by the spark plug manufacturer and Aston Martin; many modern plated-thread plugs must be installed dry. If anti-seize is approved, apply a small amount to the threads only, keeping compound away from the electrode and insulator, and reduce torque accordingly. Apply sparingly - excess anti-seize can contaminate the combustion chamber. Note: Check the spark plug manufacturer's specification regarding anti-seize; many modern plugs have plated threads and should be installed dry. If anti-seize is specified, apply a small amount to the threads only, keeping compound away from the electrode and insulator, and reduce torque accordingly. Note: Verify the gap specification for your specific DB9 model year against factory service documentation before installation. Note: Do not apply anti-seize unless specifically required by the plug manufacturer; most modern plated-thread plugs are installed dry. If anti-seize is specified, apply sparingly to the threads only, keeping compound away from the electrode and insulator, and reduce torque accordingly. Note: Verify the gap specification for your specific DB9 model year against factory documentation before installation; do not assume a value. Note: verify against Aston Martin factory documentation (unverified — do not assume a value)
   ⚠Never apply anti-seize to the electrode end or insulator. Contamination will cause misfires.
8. 8

   Install new spark plugs - Both banks
   Thread each new spark plug by hand into its cylinder head, turning clockwise. Each plug should thread smoothly with finger pressure for at least 3-4 full turns. If resistance is felt immediately, remove and restart - cross-threading will destroy the aluminum head. Once hand-tight, use the torque wrench and spark plug socket to tighten to the Aston Martin factory-specified spark plug torque (verify the exact value before tightening — do not use a generic figure). Work systematically through all 12 cylinders. Do not skip the torque wrench step - both under and over-tightening cause problems in aluminum heads.
   Torque spec

   Spark Plugs - Aluminum Head15 Nm (11 lb-ft)
9. 9

   Service throttle body
   Locate the throttle body on the intake plenum. Disconnect the electrical connector from the throttle position sensor. Remove the throttle body mounting bolts (verify exact count against Aston Martin documentation before removal). Carefully remove the throttle body and gasket. Inspect the throttle bore and butterfly valve for carbon deposits. Clean both sides of the butterfly valve and bore using throttle body cleaner and lint-free rags. Do not force the butterfly valve open - many are electronically controlled. Inspect the gasket and replace if damaged or compressed. Note: Remove the throttle body mounting bolts (verify exact count against factory service documentation, as the V12 may use dual throttle bodies). Note: Remove the throttle body mounting bolts (verify exact count against factory documentation). Note: count per Aston Martin factory documentation (unverified)
   Torque spec

   Throttle Body Bolts10 Nm (7 lb-ft)
10. 10

    Replace air filter and inspect intake system
    Locate the air filter housing (typically on driver side of engine bay). Release the housing clamps or fasteners (usually spring clips or Torx screws). Separate the housing halves and remove the old air filter element. Inspect the housing interior for debris, oil contamination, or damage. Clean housing with a damp cloth if needed. Install the new air filter ensuring proper seating and directional flow arrows if marked. Secure housing ensuring all sealing surfaces mate properly and clamps are fully engaged.
11. 11

    Replace cabin air filter
    Locate the cabin air filter per Aston Martin service documentation for the DB9 (access location and removal method vary; confirm before proceeding). Remove the access panel/door as specified, note airflow direction, and slide out the old filter. Note the airflow direction arrows on the old filter. Install the new cabin filter with airflow arrows oriented to match the removed filter and the housing marking. Secure the access door and reinstall the glove box.
12. 12

    Reinstall ignition coils with dielectric grease
    Apply a thin coat of dielectric grease to the inside of each ignition coil boot. This prevents moisture intrusion and aids future removal. Install each coil into its corresponding spark plug well, ensuring the boot seats fully onto the spark plug terminal - you should feel a positive click or seating. Install the coil mounting bolt and tighten to specification. Reconnect the electrical connector to each coil, ensuring the locking tab clicks into place. Repeat for all 12 coil packs.
    Torque spec

    Ignition Coil Bolt8 Nm (6 lb-ft)
13. 13

    Inspect and reinstall throttle body
    Position a new throttle body gasket (or reuse if undamaged) onto the intake manifold mounting surface. Align the throttle body to the mounting studs or holes and install mounting bolts finger-tight. Tighten bolts in a crisscross pattern to specification using the torque wrench. Reconnect the throttle position sensor electrical connector. Verify the throttle butterfly moves freely without binding.
    Torque spec

    Throttle Body Bolts10 Nm (7 lb-ft)
14. 14

    Reinstall engine covers and verify connections
    Reinstall all ignition coil covers, cable routing clips, and decorative engine covers removed during disassembly. Verify all electrical connectors are fully seated with locking tabs engaged. Double-check that no tools or rags remain in the engine bay. Reconnect the negative battery terminal and tighten securely.
15. 15

    Clear diagnostic codes and perform initial start
    Connect an OBD-II scanner and clear any diagnostic trouble codes stored during the procedure. Turn the ignition to ON position (do not start) and verify no warning lights illuminate on the dashboard except normal pre-start indicators. Start the engine and allow it to idle. Listen for smooth operation, unusual noises, or misfires. The engine may run slightly rough for the first 30 seconds as the ECU adapts to the new spark plugs. Verify idle stabilizes and no warning lights appear.

Reassembly

1. Ensure all 12 ignition coil electrical connectors are fully seated and locked
2. Verify all engine covers and cable routing clips are reinstalled to prevent vibration or chafing
3. Confirm throttle body gasket is properly seated to prevent vacuum leaks
4. Check that no tools, rags, or parts remain in engine bay before closing hood

Verification

• Start engine and verify smooth idle with no misfires or rough running
• Scan for diagnostic trouble codes - there should be none present
• Rev engine gently to 3000 RPM and verify smooth acceleration with no hesitation
• Perform a test drive under various load conditions to confirm proper engine performance
• Recheck all electrical connections after test drive to ensure nothing vibrated loose
• Verify no new fluid leaks around valve covers or throttle body after heat cycle
• Monitor engine performance over the next 100 miles for any abnormal behavior

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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