Car: 2007 530xi 6MT w/N52 engine 168.9k miles
So I had a cylinder 5 misfire, got a P0205 code for injector circuit cylinder 5, pulled the coilpack and saw this.
Untitled by Ayrton @ Drive19, on Flickr
Wrapped the coil in electrical tape for a week until my new coils came, installed the new coils and about a week an a half from taping up the old, bad coil, the problem resurfaces. I pull the new coil out, and the side is shredded up similar to the old one. I feel inside the spark plug tube and notice that's it very jagged and sharp, this is what the outside of tube looks like.
Untitled by Ayrton @ Drive19, on Flickr
Untitled by Ayrton @ Drive19, on Flickr
I ground down the rough edges on the inside so I wouldn't slice up another coil, and installed one of the undamaged ones I replaced. However, the issue still persisted, so I pulled the plug.
Untitled by Ayrton @ Drive19, on Flickr
looked kinda rich, figured it could possibly be fouled so I cleaned it up and reinstalled, no difference. I also tried another coil just incase the old one I recycled was bad, again no difference. I checked the wires coming from the coil pack connector, and they appear to be fine. Cylinder 1, although not misfiring, has a similar hole, although it's much smaller and didn't require me to grind it off.
Does anyone have the slightest idea as to what could have caused this? I'm all out of ideas at this point and I'm beginning to get worried.
Silver Grey Metallic 2007 530xi "Effy" - 6MT | Sport Pkg| Premium Pkg | Cold Weather Pkg | Logic7
Your valve cover is magnesium and breaks down over time. Pretty common but yours is worse than average.
there is nothing internally wrong but you do need a valve cover and bolt kit.
lastly the coils need replaced due to the jacket damage.
I don't believe that hole in your coil well will cause a misfire. But a coil with jacket damage will. Did you damage the new coil when you installed it?
You probably have another coil going out. There is a coil bulletin for all N52, N52K, N54, N55 engines to replace ALL the coils from Bosch to Delphi due to they all usually start failing in a relatively short amount of time. The Bosch coils are complete junk. The SIB is 12 18 14. Google it. The new coils have metal jackets instead of thin rubber like the one in the picture.
i see you already removed the spark plug, have you replaced all the plugs? Are they torqued to 30nm? DO NOT put anti seize/never seize on the threads. This is a common backyard mechanic practice and it's not necessary if you use OEM NGK plugs as they have a crush washer on them. Only aftermarket Bosch plugs are wierd to torque properly.
Is there any check engine lights? If not try driving the vehicle. Start off and immediately put the car in the highest gear you can and floor it. ( your trying to put a high load/low RPMS ) on it. This will usually cause the suspect coil to fail completely and set a check engine light. You'll know if it's working cause you'll feel the misfire getting worse.
If doing this does not change the misfire you could have another issue.
Last edited by SlackTube; 05-26-2017 at 08:00 AM.
The replacement coil was not damaged when installed, since posting this I have swapped at least 4 different coils that were all known to be good. I have no replaced all the plugs, I moved cylinder 5's plug to cylinder one and vise versa, the car ran fine for half a mile and then started misfiring again and the CEL illuminated. I replaced the cylinder 1 plug (which was originally in cylinder 5) and no dice, scanned the car and found that cylinder 5 was still misfiring. I showed the replaced plug to a BMW tech and he said it looked fine. On my way home yesterday the car did start driving normal momentarily, I then dropped it into 2nd and did a pull to 6k rpm (6k is when it historically had a slight hesitation before this situation escalated) and then it began misfiring again. I can try putting the new plug in cylinder 5, it is an NGK plug, OE spec but does not have BMW branding on it. I'll also check to make sure they are torqued tight enough as well.
The car is producing the code P0205 for cylinder 5 injector circuit, the BMW tech that looked it over said that he's never seen an injector go bad on an N52, but to swap out cylinder 5's injector with that of another cylinder and see if the problem follows the injector. However, swapping coils temporarily solve the issue a couple times, so it still seems ignition related to me rather than fueling, especially since the car has had a couple moments of running fine .
Silver Grey Metallic 2007 530xi "Effy" - 6MT | Sport Pkg| Premium Pkg | Cold Weather Pkg | Logic7
Don't you think that you should change spark plug number 5? Or maybe check fuel injector #5? You've already determined that it's not the coil. How many times do you want to swap things around before you move on to where the problem might be?
gmak: The Good, the Bad, and the Ugly. A journey with my new-to-me 2000 540i
"Working on a BMW E39 is the best way to run out of time."
I changed spark plug 5 with the plug from cylinder one already, I was just going to try putting a brand new one in to see if that did anything, I doubt it will but worth a try I guess. Checking fuel injector 5 is also next on the list as I mentioned previously.
The coils were just swapped out so many times because after I checked them, a tech a work checked them as well.
Silver Grey Metallic 2007 530xi "Effy" - 6MT | Sport Pkg| Premium Pkg | Cold Weather Pkg | Logic7
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