DB9 Workshop Manual

Random Ticking and Misfire

Only 1,200 miles after replacing all the coils and plugs the car developed a random ticking sound and misfire at idle. It would disappear even with the slightest increase in engine speed over idle. The ticking sound, which was coming from the #6 cylinder area, turned out to be sparking. I would see sparks at random near the ground bolt near #6 and also on other random areas on the RHS intake manifold. Here is a video clip. I was never able to capture the sparking on camera. I inspected all the grounds. They were in excellent condition. I even ran the car with the battery -ve directly connected to the alternator body. But it made no difference. I physically couldn't see anything wrong with the #6 coil or spark plug. I first replaced the spark plug, but that didn't do anything. So I decided to replace the #6 coil as well and that seems to have fixed the issue. I removed and refit the RHS intake manifold twice while troubleshooting. I've become quite good at it. Here are a lis...

Coil Pack Service

On the plus side, after production moved to Germany, these V12s became very reliable, not having any major issues. But on the negative, they like to eat ignition coils faster than most cars. Likely due to the coils buried deep under the intake manifolds with absolutely no air circulation. And this, once every 30k mile service is a major pain in the butt. If everything goes perfect (very unlikely given how old these cars are now), it takes about 6 hrs to R&R the coils and spark plugs. I would budget about 3x that time if its your first time and you just want to take your time and enjoy freshening things up as you go. Most of the major parts can be readily purchased without the Aston tax directly from Ford, NGK etc.. But the intake gasket is quite unique. And not really worth modifying the v6 Mondeo ones. The PCV valves are also another issue. Although the valve itself is just a $2 Motorcraft part, the harness its glued into is not readily available. One would have to make something ...

V12 English Spy

Search This Blog