Cylinder #4 misfire

30564DAN · 04-20-2014, 08:43 AM

Hey guys,

I hope someone can help me!

I have a 2006 BMW 530i (N52) with 85,000 miles. About four years ago, after I changed the spark plugs (for better MPG) and coolant as preventative maintenance, I started getting SES for cylinder #4 misfire. Even with that problem, engine have run strong, smooth and quiet since then. The same SES (#4 misfire) comes on only when I start the car. So I dealt with the problem by "manually" clearing the code each time I drive off. After SES is manually cleared , it does not come on no matter how long or hard I drive the car. Note, it only come on when I start the car.

In the last four years, I was convinced that it was just a system glitch! I was certain the three wires that connects to the ignition coil plug for #4 was the culprit. They had broken insulators and might no longer have 100% integrity after they are patched up; due to high engine temperature heat melting them at one point or another. I didn't think the random electricity arcing from the problematic wires for the ignition coil plug was a big deal as long as my car runs smooth and quiet.

To keep my story short, I have replaced six new ignition coils and the cable harness (part #12517556871) a few days ago. I have also swap the NGK laser iridium spark plugs (with 35k miles) around. Thus far, the same SES is still coming on.

My car runs quiet and strong. I do feel the mild misfire in PARK and STOP positions. To point out how mild my misfire is, if the SES isn't telling me that cylinder #4 is misfiring, I would think my engine mounts are slightly worn and it's no big deal. Just yesterday, when I was coming into a parking space at the park, two cars in between with doors opened could not tell nor noticed that I was waiting within less than a couple yards. Therefore, I am doubtful there is any mechanical issue.

Since this problem has been going on for almost four years, do you think all it takes is to reset the computer to get it to adapt to new parts? And how can I do that? Any suggestions to get rid of this same annoying SES is greatly appreciated!

FYI: Attached is a link to the new cable harness that I replaced because I thought the repair for the wires for the ignition coil plug for cylinder #4 was not good enough to fix the misfire. http://www.realoem.com/bmw/showparts...41&hg=12&fg=28

Thank you,

Daniel

04-20-2014, 08:43 AM	#1
30564DAN Registered 0 Rep 1 Posts Drives: 2006 BMW 530I Join Date: Apr 2014 Location: SOCAL iTrader: (0)	Cylinder #4 misfire Hey guys, I hope someone can help me! I have a 2006 BMW 530i (N52) with 85,000 miles. About four years ago, after I changed the spark plugs (for better MPG) and coolant as preventative maintenance, I started getting SES for cylinder #4 misfire. Even with that problem, engine have run strong, smooth and quiet since then. The same SES (#4 misfire) comes on only when I start the car. So I dealt with the problem by "manually" clearing the code each time I drive off. After SES is manually cleared , it does not come on no matter how long or hard I drive the car. Note, it only come on when I start the car. In the last four years, I was convinced that it was just a system glitch! I was certain the three wires that connects to the ignition coil plug for #4 was the culprit. They had broken insulators and might no longer have 100% integrity after they are patched up; due to high engine temperature heat melting them at one point or another. I didn't think the random electricity arcing from the problematic wires for the ignition coil plug was a big deal as long as my car runs smooth and quiet. To keep my story short, I have replaced six new ignition coils and the cable harness (part #12517556871) a few days ago. I have also swap the NGK laser iridium spark plugs (with 35k miles) around. Thus far, the same SES is still coming on. My car runs quiet and strong. I do feel the mild misfire in PARK and STOP positions. To point out how mild my misfire is, if the SES isn't telling me that cylinder #4 is misfiring, I would think my engine mounts are slightly worn and it's no big deal. Just yesterday, when I was coming into a parking space at the park, two cars in between with doors opened could not tell nor noticed that I was waiting within less than a couple yards. Therefore, I am doubtful there is any mechanical issue. Since this problem has been going on for almost four years, do you think all it takes is to reset the computer to get it to adapt to new parts? And how can I do that? Any suggestions to get rid of this same annoying SES is greatly appreciated! FYI: Attached is a link to the new cable harness that I replaced because I thought the repair for the wires for the ignition coil plug for cylinder #4 was not good enough to fix the misfire. http://www.realoem.com/bmw/showparts...41&hg=12&fg=28 Thank you, Daniel Last edited by 30564DAN; 04-20-2014 at 09:02 AM..
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