[renoir408]

Originally Posted by Saif2018

They are pre gapped, they're not supposed to be gapped.

Your masking the problem and those plugs probably won't last long.

I agree with you. Maybe the plugs will not support this gap for a long period, but is the first time that I’m happy with my car.

This weekend I will try a intermediate plug gap to see the impact.

Sincerely the last 3 months I have tried all that was possible with the support of bmw dealer with no results.

Someone else have a opinion on that? Regards.

[Saif2018]

Originally Posted by renoir408

I agree with you. Maybe the plugs will not support this gap for a long period, but is the first time that I’m happy with my car.

This weekend I will try a intermediate plug gap to see the impact.

Sincerely the last 3 months I have tried all that was possible with the support of bmw dealer with no results.

Someone else have a opinion on that? Regards.

Have you got any logs?

[renoir408]

Originally Posted by Saif2018

Have you got any logs?

I made some tours with the scanner logged and any misfires or other abnormal parameters showed.

Nb. I have a spark plug test and I can test and see the behavior of the spark before install it in the car. With the original gap the perf of the plug ridiculous. I will try to make a video with the original one and the adjusted gap.

[renoir408]

Originally Posted by renoir408

I made some tours with the scanner logged and any misfires or other abnormal parameters showed.

Nb. I have a spark plug test and I can test and see the behavior of the spark before install it in the car. With the original gap the perf of the plug ridiculous. I will try to make a video with the original one and the adjusted gap.

UPDATE!
In the spark plugs bmw box it’s noted gap 0.7mm. For my surprise I measured 0.5mm for all my new plugs.

I still running with 0.9mm and the engine runs very smoothly after 300 km. I just inspected all the sparks and it’s very clean.

[bcb01]

Resurrecting this thread, but I wanted to document my own findings.

TLDR;

Symptom: subtle misfire at warm idle after spark plugs changed
Resolution: re-gap the plugs that were replaced

----------------------------------------------------------------------------


2007 e90 70k mile n54 all stock

Decided to replace valve cover, spark plugs (OE bosch ZGR6STE2), coil packs (Eldor brand from FCP) and convert to an external RB PCV system.

All the original parts were probably 18 y/o factory BMW. However, after the above maintenance, I started to feel the same symptoms that renoir408 experienced:

• slight misfire at idle (around 650 RPMs)
• warm engine (above 200 F oil temps)
• no a/c
• low load

After the DME detects a few slight misfires the commanded RPM raises to 800 RPM. No shadow codes or actual codes were thrown per protool and MHD.

Took the bosch plugs back out and gapped to .9mm (0.035") and the engine idles really happy now. I noticed too that the original gap on the bosch plug are smaller than the advertised .7mm gap (more like .5mm as renoir408 mentioned). After re-gapping, the car still pulls to redline without any issues or misfires.

Below is the type of tool that I used to gap the plugs (copied image from porsche forum )

Remember, this is just one instance surrounding a specific set of circumstances, and "your mileage may vary", but at least this post could help someone else out.

Thanks!