Hey guys - curious if anyone had insight (knowing this is a shot in the dark ask) on what would cause a Cylinder 4 Misfire, with the ticking sound in the linked video.

There was one other fault along side the Cylinder 4 Misfire, ESC + TC. These faults would reset themselves on a restart of the car. Faults would not return below 3K RPM but car wasn’t running as ‘smooth’ as usual. Above 3K the faults would return and the car runs much ‘rougher’.

We have replaced coils and plugs to no avail.

Thanks in advance for any thoughts.

 

Sounds like piston slap.

 

Thanks. It doesn’t go away when the engine is up to temp. It is my understanding that piston slap and the sound are reduced/go away when the engine is brought up to temp.

 

Typically it does, until it doesn't.
It's possible that the Cylinder 4 Misfire is from the piston rocking and triggering the knock sensor.
This in turn could possible pull the timing (causing the rough idle/run)
Do you have a mechanics stetescope? You may be able to get under there and listen.

 

We do. We were going to perform a leak down test on that cylinder as well. Would that reveal anything as it relates to piston slap?

 

In addition if you have a boroscope (cheap on amazon), take a peak into the cylinders.

 

Compression and Leak Down would be a good idea to start investigating.
I'm no mechanic, but if the cylinder wall is scored up; the compression test/leak down should pick it up.
Also, get a stetescope, I got mine from harbor freight; it saved me once from taking an engine apart.

 

Fingers crossed we aren’t to that point (cylinder wall scoring or worse). More to come this week...

 

Fuel injector noise with associated misfire? I'm trying to be an optimist.

EDIT: Now that I listen to the video, I can't be an optimist. Sounds like it's due to mechanical clearance.

 

Deleted

 

Leakdown test is needed. If that's bad, then you can use a borescope to find out the extent of the damage. Is this a 981 or a 718?

 

Thanks. It is a 981; early 2015 build. No known pre-existing engine issues so pretty surprised to be at this point.

 

Sorry to hear, agree, that's a mechanical issue and needs attention. How many miles does the car have? These stories are popping up more and more now with 981 GT4 engines.

 

Gosh, sounds terrible. Please let us know about the final diagnosis and fix.

 

The car has 35K miles most of which were street miles.

Yeah, not thrilled for sure. I will definitely keep everyone posted. Thanks.