How To Fix Ovaled/Loose Injector Bore (No More N54 Misfires!)

suspenceful · 05-17-2023, 03:31 PM

If you own a BMW with an N54 engine, you may have heard of the issue where the injector bores become loose. In this post, I'll explain what that means, why it happens, and how to fix it with the PPI injector bore repair kit.

If you didn't know, the injector bore is the hole in the head of the engine where the fuel injector sits. And if it becomes loose, that means the injector isn’t getting a proper seal to the engine. This can cause a number of problems including misfires, rough idling, and poor performance due to lost compression. And if left unfixed, it will continue to get worse and eventually make your BMW undrivable.

So why does it happen? Well, it's often due to improper injector installation or removal. With these cars being notorious for bad injectors, it’s not uncommon for them to be replaced (albeit improperly). If they were pulled side-to-side while being removed, instead of being pulled up with the proper tool, you can immediately oval out the bore. Fortunately, it can be fixed.

If you catch the damage early like I did, you can fix the bore without replacing the entire head, which can be a very expensive repair upwards of $12,000! The fix I showed in the video above requires a $500 kit from PPI and some patience. It involves rethreading the injector bore and installing a new insert to securely hold the injector in place.

I show every step you'll need to do in the video above, and in my experience, it worked flawlessly. The bores were actually tighter than they were from the factory, the injectors fit so snug I had to use a bit of force... but no more issues!

I've tried the teflon tape and copper washer, but neither worked for me long-term. This is the only proper way to fix this issue.

fast1eddy · 05-18-2023, 12:00 AM

I watched your video on this a few days ago. It looks pretty straight forward but I’d be nervous about metal shavings in the engine. I’d be constantly wondering if I got them all out.

suspenceful · 05-22-2023, 02:31 PM

Quote:

Originally Posted by fast1eddy

I watched your video on this a few days ago. It looks pretty straight forward but I’d be nervous about metal shavings in the engine. I’d be constantly wondering if I got them all out.

Yeah, I know what you mean... but as long as you're tedious about blowing them out, I think you'll be okay.

05-17-2023, 03:31 PM	#1
suspenceful Major 1024 Rep 1,264 Posts Drives: 2015 M3, 2008 135i, 2009 335i Join Date: Feb 2014 Location: WI iTrader: (9)	How To Fix Ovaled/Loose Injector Bore (No More N54 Misfires!) If you own a BMW with an N54 engine, you may have heard of the issue where the injector bores become loose. In this post, I'll explain what that means, why it happens, and how to fix it with the PPI injector bore repair kit. If you didn't know, the injector bore is the hole in the head of the engine where the fuel injector sits. And if it becomes loose, that means the injector isn’t getting a proper seal to the engine. This can cause a number of problems including misfires, rough idling, and poor performance due to lost compression. And if left unfixed, it will continue to get worse and eventually make your BMW undrivable. So why does it happen? Well, it's often due to improper injector installation or removal. With these cars being notorious for bad injectors, it’s not uncommon for them to be replaced (albeit improperly). If they were pulled side-to-side while being removed, instead of being pulled up with the proper tool, you can immediately oval out the bore. Fortunately, it can be fixed. If you catch the damage early like I did, you can fix the bore without replacing the entire head, which can be a very expensive repair upwards of $12,000! The fix I showed in the video above requires a $500 kit from PPI and some patience. It involves rethreading the injector bore and installing a new insert to securely hold the injector in place. I show every step you'll need to do in the video above, and in my experience, it worked flawlessly. The bores were actually tighter than they were from the factory, the injectors fit so snug I had to use a bit of force... but no more issues! I've tried the teflon tape and copper washer, but neither worked for me long-term. This is the only proper way to fix this issue. __________________ 750whp 135i Build \| Budget 335i Build \| F80 M3 Build 🎬 YouTube channel (35K+ subs): youtube.com/jakespence135 📷 Follow me on Instagram: instagram.com/jakespence 🏁 Shop BMW merchandise: bimmerstreet.com
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05-18-2023, 12:00 AM	#2
fast1eddy First Lieutenant 270 Rep 367 Posts Drives: 2008 135i Lemans Blue Join Date: Jul 2013 Location: Edmonton iTrader: (1) Garage List 2008 135i [0.00] [0.00]	I watched your video on this a few days ago. It looks pretty straight forward but I’d be nervous about metal shavings in the engine. I’d be constantly wondering if I got them all out.
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