Each cylinder in your DB9 V12 engine has its own individual coil pack installed on top of the spark plug right down in the valve cover area. You might need to remove the coil packs to replace them, or service the spark plugs, or to remove the valve cover or something deeper in the engine. I’m replacing mine since my car is suffering from a Lumpy Idle (see my post on this). Removing them is pretty easy once you have the preliminary work necessary to access them out of the way.I’ve done a lot of work already getting to this point, including the steps detailed in these other posts and videos:
- Depressurizing your fuel system (so you don’t start a fire)
- Disconnecting your Battery (also so you don’t start a fire)
- Covering your fenders (so you don’t screw up your paint)
- Removing the Engine Bay Cross Braces (because it’s in the way)
- Removing the Intake Manifold Brace (because it’s in the way)
- Disconnecting the Fuel Rails and removing the Fuel Injectors (because they are attached)
- Disconnecting all the other ancillary components attached to the manifolds (also in the way)
- Removing the Intake Manifolds
- Removing the Spark Plug Covers
- 7mm 6-point Socket
- A suitable ratchet
- A suitable nut driver to make the process go faster
If you have all the preliminaries noted above already out of the way this step only takes about 5 minutes per side. Easy.
The official Aston Martin Workshop manual section on Spark Plugs covers it in steps 3 & 4 “Disconnect Coil Packs” and “Remove Coil Packs”. Succinct. Here’s my slightly more verbose version with a few tips:
- Disconnect the electrical connections to the coil packs by squeezing and pulling the connector off.
- Remove the bolt holding the coil pack in place using the 7mm 6-point socket and ratchet.
- After you crack them all lose you might want to switch to the nut driver to speed the process along.
- Once you’ve removed the twelve (12) bolts, set them aside on your workbench so they aren’t laying around in the engine compartment. Be careful that they don’t find their way into the intake chambers or engine block V area.
- Time to remove the coil packs.
- If you plan to reuse them, the mechanic in me says you should be careful and label them so they get returned to the exact same cylinder location. The DB9 has a sophisticated misfire correction system and its tuned to the performance of each cylinder’s electronic components, so if you return the coils back to the original spot you won’t have to worry about relearning the misfire correction factors (check out my blog post on this).
- Remove them by simply gripping them firmly and wiggling them up and out.
That’s it. You should have your coil packs out and sitting nicely on the bench now.
NOTE: You might take a quick peek at the electrical connections on your coil pack now. There are two iterations of coil packs, early cars seem to have ‘2 pin’ coil packs, and later cars have ‘3 pin’. My dealer and parts people couldn’t look up for sure, so I just guessed and bought the 2 pin version. You’ll want to confirm you have the right version if you are replacing them. [If anyone knows the definitive cutover point between 2 and 3 pin cars, please leave me a comment below]
Here is a quick video of the process I followed:
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