986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post

geraintthomas · 12-31-2015, 09:25 AM

I've had this problem for a few days now.

Driving the car normally, it's fine. I can take the car up to the red line at running temperatures and it starts fine, but a couple of minutes of hard driving and the engine sounds AWFUL.

Spluttering all the way up through the rev range, but not on idle. It idle's fine. Unless I keep accelerating hard and eventually you can hear it at lower revs and idling. However, if I stop driving hard and start driving carefully again, it goes completely back to normal. After a few minutes, I can take the revs right up and it sounds perfect, until it starts over again...

It's clearly heat based, and I think it's ignition related, otherwise it would happen all of the time. I'm getting no CEL's or any errors from the OBD2 port of any kind.

Some guys said it could be the coil packs, so I went to take a look:

First thing I noticed was that Cylinder 6 had no orange rubber on the plug. I managed to find one from an old HID kit, so I fixed that.

Most of the coil packs look like this:

However, the pack on cylinder 6 (the one with the missing rubber) looked like this:

A friend has given me 6 coil packs and 6 spark plugs to try out. I only had time to replace the one pack, the one shown above. But it didn't fix it.

On closer inspection of that coil pack, the end has rubber missing (which thankfully I found):

But, even with a replacement coil pack to replace this one, it's still misfiring.

I managed to get a video after pulling over immediately after driving hard. You can hear it in the start of the video, and then (as the engine starts to cool), it eventually goes back to normal.

https://www.youtube.com/watch?v=7IQ35nZllds

Sounds like an air cooled when it happens...

Now when the weather permits, I need to replace all spark plugs and all coil packs with these known working replacements that I have, so that I can rule them out. Could moisture have gotten onto the number 6 spark plug from that damaged bit of rubber and damaged the plug? Either that or the other 5 coil packs are the culprit, which I haven't had chance to swap. Or their spark plugs...

But in the meantime, what do you guys think is the issue? Also, can someone confirm that the issue as described (and as shown quite poorly in the video, sorry), that this is probably a misfire? I originally thought the exhaust was blowing, but surely it would happen all the time and, if anything, go away if the exhaust got hotter?

Any help would be lovely!

Thanks

12-31-2015, 09:25 AM	#1
geraintthomas Registered User Join Date: Nov 2015 Location: South Wales, UK Posts: 852	UPDATE: Boxster 3.2 S engine problem! Exhaust blow? I've had this problem for a few days now. Driving the car normally, it's fine. I can take the car up to the red line at running temperatures and it starts fine, but a couple of minutes of hard driving and the engine sounds AWFUL. Spluttering all the way up through the rev range, but not on idle. It idle's fine. Unless I keep accelerating hard and eventually you can hear it at lower revs and idling. However, if I stop driving hard and start driving carefully again, it goes completely back to normal. After a few minutes, I can take the revs right up and it sounds perfect, until it starts over again... It's clearly heat based, and I think it's ignition related, otherwise it would happen all of the time. I'm getting no CEL's or any errors from the OBD2 port of any kind. Some guys said it could be the coil packs, so I went to take a look: First thing I noticed was that Cylinder 6 had no orange rubber on the plug. I managed to find one from an old HID kit, so I fixed that. Most of the coil packs look like this: However, the pack on cylinder 6 (the one with the missing rubber) looked like this: A friend has given me 6 coil packs and 6 spark plugs to try out. I only had time to replace the one pack, the one shown above. But it didn't fix it. On closer inspection of that coil pack, the end has rubber missing (which thankfully I found): But, even with a replacement coil pack to replace this one, it's still misfiring. I managed to get a video after pulling over immediately after driving hard. You can hear it in the start of the video, and then (as the engine starts to cool), it eventually goes back to normal. https://www.youtube.com/watch?v=7IQ35nZllds Sounds like an air cooled when it happens... Now when the weather permits, I need to replace all spark plugs and all coil packs with these known working replacements that I have, so that I can rule them out. Could moisture have gotten onto the number 6 spark plug from that damaged bit of rubber and damaged the plug? Either that or the other 5 coil packs are the culprit, which I haven't had chance to swap. Or their spark plugs... But in the meantime, what do you guys think is the issue? Also, can someone confirm that the issue as described (and as shown quite poorly in the video, sorry), that this is probably a misfire? I originally thought the exhaust was blowing, but surely it would happen all the time and, if anything, go away if the exhaust got hotter? Any help would be lovely! Thanks Last edited by geraintthomas; 01-07-2016 at 02:20 PM.