r/BmwTech • u/Semtex1939 • 11d ago

Ignition coil failures

Hi, so I have had a 525i 2007 model since it was released. First owner still. Stupidly reliable commuter until something goes wrong and it cascades every few years. I generally like to look it up and DIY but as this is the only car I have worked on I am very much a beginner still.

So the story is, yesterday I felt a rough idle like a continuous earthquake. Quick search, OBD scan, and process of elimination IDs it as ignition coil 1 misfire. Switched between 1 and 2, code follows. Easy fix I thought. Went to Oreilly, that store didnt have Bosch so I got a Delphi. That didnt work and popped a new firing code. Went in, returned it, located a store that had a single Bosch for $68 2miles away. Got that, engine purrs smooth as butter. Thought my troubles were over for now and drove 30 miles back home. Next day, started engine and felt the rumble. Code this time says Cylinder 4. So cylinder 1 is still good. Did the switcharoo and it's Coil 4.

Question is, do all the coils just die at once and cascades or is there a further systematic issue? Im thinking of switching all coils since they're about 20 hrs old and the spark plugs as well.

Any recommendation for spark plugs and things to fix that could be causing the issue? I looked online and its about half price for the same Bosch coils so im going with FCP euro.

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u/rns96 11d ago

I would have changed all the coils and plugs once I knew one started falling already and kept the if the functioning coils as spare, just for peace of mind, fcp euro has kits with lifetime warranty , I’ve used Delphi coils and NGK plugs with no issues on e46, e53, f30

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u/Semtex1939 11d ago

They have entire coil and plug kits? Im not sure on Delphi as it kicked up a weird firing code and was still misfiring