"ticking" around the dist cap

[bytes311]

I recently performed a basic tune-up with a new cap, rotor, and spark plug wire set from DMCH. After triple-verifying the order of the wires and putting it all back together, there is now a distinct "ticking" sound within proximity of the distributor cap, which has no pattern that I can tell. The "ticking" affects the RPM at idle as it makes the engine stumble momentarily. It's only noticeable at idle. The engine runs great otherwise. It definitely sounds electrical. Has anyone encountered this before?

Here is a video of the "tick:" https://youtu.be/rV_-WNTXC7U

Thanks!

[opethmike]

Completely unrelated car, but I had a VERY similar sound when I recently did headers on my Corvette. Turned out that one of my spark plug boots was not fully seated, so sometimes it would arc, sometimes it would not.

[Bitsyncmaster]

Sounds like a cross fire. With a new cap, would not expect any cross fire. With an old cap you would clean the cap to remove any condensation and carbon tracks.

Are your plugs gaped wider than stock gap?

[bytes311]

Sounds like a cross fire. With a new cap, would not expect any cross fire. With an old cap you would clean the cap to remove any condensation and carbon tracks.

Are your plugs gaped wider than stock gap?

Interesting. No, my plugs are properly gaped. They are Bosch HR6DS and fairly new as of last year.

[Ron]

I'd go with Mike's idea -- Spark has to be jumping for you to here it.
Seeming to clear up after breaking idle fits to, if it is jumping along the normal path.
If so, you might catch it using a timing light on the easy to get to wires (skippy pattern etc...).
Or, pull the wires one at a time (plug end) looking for one that causes the miss to never recover....

Good luck!

[David T]

I'd go with Mike's idea -- Spark has to be jumping for you to here it.
Seeming to clear up after breaking idle fits to, if it is jumping along the normal path.
If so, you might catch it using a timing light on the easy to get to wires (skippy pattern etc...).
Or, pull the wires one at a time (plug end) looking for one that causes the miss to never recover....

Good luck!

It is possible when you changed the wires you stretched the inner core of a wire and broke it. One way to find the problem is to run the motor in the dark, put your hands in your pockets, and see if you can spot a blue spark jumping when you hear the ticking. If you don't see a spark make sure each wire is firmly inserted all the way into the dist cap. Other possible causes, a rotor that is not fully seated or the spark is jumping from it to the shaft in the distributor, the cap is not properly seated on the distributor, the cap is damaged and the spark is jumping inside the cap. if you take things apart again look for carbon tracking. If you smell Ozone that is a big tip that you have sparking. If you don't fix it, it will only get worse.

[Ratrace427]

Agreed...It's a spark leak. Checking in the dark is a good way to find the leak. Interesting that a set of new wires would leak. The spark will most likely leak where the wire comes close to a steel bracket. For example the engine hoist loop on the passenger side. The wire group runs right by it on the back side of the engine.

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[SS Spoiler]

put your hands in your pocket?

[David T]

put your hands in your pocket?

Yes, the reasons I say that is so you won't get your hands caught in anything moving (belts and pulleys) touch anything hot, or have the spark pump into your hands. Too tempting to use your hands so keep them in your pockets! Remember you are doing this in the dark.

[bytes311]

Thank you all. I thought I was going to have to tear down the engine and replace all three components just to be safe, but I was able to locate and identify the source of the "ticking" in the dark. One of the spark plug wires (either #4 or #5) was pinched between the block and the metering unit and grounded itself out. I rerouted the wires away from the engine and that solved it.