F80 misfire

Tymula_81 · 11-20-2022, 10:12 AM

So currently my car has a small misfire at idle but once I get passed 2k rpm the car runs fine. I changed the plugs,injectors,running compression test and tested the coils. Idk what else try. Back story is I was tuning my pi with f80 Paul and I kept getting a studder after 65k rpm. As i was changing the plugs i notice the old one had a small piece broke. I installed the new ones and still had the same problem. then he adjusted the pi. The car ran fine for a week while tuning then as I stopped at a Light I felt the misfire. I'm clueless right now any suggestions would be greatly appreciated.

TopJimmy · 11-20-2022, 11:01 AM

I'm wondering where the piece of ceramic went… What was the compression test result on that cylinder versus the others?

Tymula_81 · 11-20-2022, 11:06 AM

Quote:

Originally Posted by Tymula_81

So currently my car has a small misfire at idle but once I get passed 2k rpm the car runs fine. I changed the plugs,injectors,running compression test and tested the coils. Idk what else try. Back story is I was tuning my pi with f80 Paul and I kept getting a studder after 65k rpm. As i was changing the plugs i notice the old one had a small piece broke. I installed the new ones and still had the same problem. then he adjusted the pi. The car ran fine for a week while tuning then as I stopped at a Light I felt the misfire. I'm clueless right now any suggestions would be greatly appreciated.

That cylinder compression was a little higher then the rest. I just posted pics

JAI///M3 · 11-20-2022, 01:07 PM

How did you test the coils? Are you able to isolate which cylinder(s) are misfiring with a datalog? The cylinder pressure spread seems a little wider than I would've thought but nothing too alarming.

Tymula_81 · 11-20-2022, 02:21 PM

Quote:

Originally Posted by JAI///M3

How did you test the coils? Are you able to isolate which cylinder(s) are misfiring with a datalog? The cylinder pressure spread seems a little wider than I would've thought but nothing too alarming.

I unplugged each coil and all of them had a reaction

JAI///M3 · 11-20-2022, 03:36 PM

Quote:

Originally Posted by Tymula_81

Quote:

Originally Posted by JAI///M3

How did you test the coils? Are you able to isolate which cylinder(s) are misfiring with a datalog? The cylinder pressure spread seems a little wider than I would've thought but nothing too alarming.

I unplugged each coil and all of them had a reaction

A weak or failing coil may perform ok at or near idle speeds but fall on its face at higher rpm. If you're able to identify which cylinder(s) are misfiring, you can then swap coils from those cylinders and see how they respond at higher rpms

Tymula_81 · 11-20-2022, 03:57 PM

Quote:

Originally Posted by JAI///M3

Quote:

Originally Posted by Tymula_81

Quote:

Originally Posted by JAI///M3

How did you test the coils? Are you able to isolate which cylinder(s) are misfiring with a datalog? The cylinder pressure spread seems a little wider than I would've thought but nothing too alarming.

I unplugged each coil and all of them had a reaction

A weak or failing coil may perform ok at or near idle speeds but fall on its face at higher rpm. If you're able to identify which cylinder(s) are misfiring, you can then swap coils from those cylinders and see how they respond at higher rpms

That's the weird part. I took a hit on the car and it doesn't lose any power. I did 3rd 4th and 5th gear and it drives like a champ

Tymula_81 · 11-20-2022, 04:00 PM

I looked at the piston and this but I can't tell what it is. People saying it's fine but idk

JAI///M3 · 11-20-2022, 04:24 PM

Quote:

Originally Posted by Tymula_81

I looked at the piston and this but I can't tell what it is. People saying it's fine but idk

Wow. Is that the cylinder that had the broken spark plug? I wonder if that's where the piece ended up..? If it was actually damaged I imaging the compression would be way lower.

Tymula_81 · 11-20-2022, 04:26 PM

Quote:

Originally Posted by JAI///M3

Quote:

Originally Posted by Tymula_81

I looked at the piston and this but I can't tell what it is. People saying it's fine but idk

Wow. Is that the cylinder that had the broken spark plug? I wonder if that's where the piece ended up..? If it was actually damaged I imaging the compression would be way lower.

Yea that was the cylinder. A friend of mine said it probably melted. And the compression on that cylinder was a little higher then them all

JAI///M3 · 11-20-2022, 04:31 PM

Yeah that would makes sense. If the additional porcelain volume is now in the chamber, it would raise static compression. Luckily that was the worst it did.

Tymula_81 · 11-20-2022, 04:34 PM

Quote:

Originally Posted by JAI///M3

Yeah that would makes sense. If the additional porcelain volume is now in the chamber, it would raise static compression. Luckily that was the worst it did.

I'm just clueless.I don't wanna dump anymore money into the car until I can find out if the motor is good or not

Track/S · 11-20-2022, 05:31 PM

What is the mileage of the spark plug of the picture?

Tymula_81 · 11-20-2022, 05:50 PM

Quote:

Originally Posted by Prodrive_X

What is the mileage of the spark plug of the picture?

Not even 300 miles they where new

Wanted_M · 11-20-2022, 08:26 PM

That cylinder is hella low, bummer man.

Tymula_81 · 11-20-2022, 08:30 PM

Quote:

Originally Posted by Wanted_M

That cylinder is hella low, bummer man.

What cylinder

JAI///M3 · 11-20-2022, 09:10 PM

Assuming the photos are in order, cylinders 3 and 6 look to be around #105 where the rest are closer to #120-130. It's not like they're dead cylinders but higher deviation than I would like

Was the engine warm when you did the test?

Tymula_81 · 11-20-2022, 09:13 PM

Quote:

Originally Posted by JAI///M3

Assuming the photos are in order, cylinders 3 and 6 look to be around #105 where the rest are closer to #120-130. It's not like they're dead cylinders but higher deviation than I would like

Was the engine warm when you did the test?

Not fully warmed up

Tymula_81 · 11-21-2022, 07:24 AM

Here is my log

https://www.bootmod3.net/log?id=637b...90c6a3cbb67255

TopJimmy · 11-21-2022, 07:40 AM

You don't get a good picture in 6th gear at low RPMs. The log needs to be a 4th gear pull from 3K up to 6500, with DCT fully off, in Sport+ mode. Make sure you get both WGDC and the LPFP added to the logging.

Tymula_81 · 11-21-2022, 09:27 AM

Quote:

Originally Posted by TopJimmy

You don't get a good picture in 6th gear at low RPMs. The log needs to be a 4th gear pull from 3K up to 6500, with DCT fully off, in Sport+ mode. Make sure you get both WGDC and the LPFP added to the logging.

https://www.bootmod3.net/log?id=636d...0b439ed7c5f697

TopJimmy · 11-21-2022, 07:33 PM

Quote:

Originally Posted by Tymula_81

Quote:

Originally Posted by TopJimmy

You don't get a good picture in 6th gear at low RPMs. The log needs to be a 4th gear pull from 3K up to 6500, with DCT fully off, in Sport+ mode. Make sure you get both WGDC and the LPFP added to the logging.

https://www.bootmod3.net/log?id=636d...0b439ed7c5f697

Timing is off on 4 and 6. Gotta investigate further.

Why is Flex reading 90% ethanol?

11-20-2022, 10:12 AM	#1
Tymula_81 Second Lieutenant 87 Rep 234 Posts Drives: F10 528 xdrive Join Date: Dec 2016 Location: Bronx ny iTrader: (0)	So currently my car has a small misfire at idle but once I get passed 2k rpm the car runs fine. I changed the plugs,injectors,running compression test and tested the coils. Idk what else try. Back story is I was tuning my pi with f80 Paul and I kept getting a studder after 65k rpm. As i was changing the plugs i notice the old one had a small piece broke. I installed the new ones and still had the same problem. then he adjusted the pi. The car ran fine for a week while tuning then as I stopped at a Light I felt the misfire. I'm clueless right now any suggestions would be greatly appreciated. Attached Images
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11-20-2022, 11:01 AM	#2
TopJimmy Major General 5445 Rep 5,137 Posts Drives: 2023 M3 Comp xDrive Join Date: Jul 2019 Location: Chester County, PA iTrader: (5)	I'm wondering where the piece of ceramic went… What was the compression test result on that cylinder versus the others? __________________ '18 F80 Base 6MT \| '19 F82 Exec DCT \| '18 F82 Comp Exec DCT \| '23 G80cx
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11-20-2022, 01:07 PM	#4
JAI///M3 Lieutenant 528 Rep 502 Posts Drives: F80 M3 Join Date: Dec 2021 Location: East Bay iTrader: (0) Garage List 2018 F80 [0.00]	How did you test the coils? Are you able to isolate which cylinder(s) are misfiring with a datalog? The cylinder pressure spread seems a little wider than I would've thought but nothing too alarming.
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11-20-2022, 04:00 PM	#8
Tymula_81 Second Lieutenant 87 Rep 234 Posts Drives: F10 528 xdrive Join Date: Dec 2016 Location: Bronx ny iTrader: (0)	Hey I looked at the piston and this but I can't tell what it is. People saying it's fine but idk Attached Images
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11-20-2022, 04:31 PM	#11
JAI///M3 Lieutenant 528 Rep 502 Posts Drives: F80 M3 Join Date: Dec 2021 Location: East Bay iTrader: (0) Garage List 2018 F80 [0.00]	Yeah that would makes sense. If the additional porcelain volume is now in the chamber, it would raise static compression. Luckily that was the worst it did.
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11-20-2022, 05:31 PM	#13
Track/S Major 1337 Rep 1,320 Posts Drives: M2C, M4 GTS Join Date: Oct 2019 Location: Around the world iTrader: (0)	What is the mileage of the spark plug of the picture?
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11-20-2022, 08:26 PM	#15
Wanted_M Captain 756 Rep 946 Posts Drives: Frozen Blue M4CS Join Date: Jul 2009 Location: Norcal iTrader: (2)	That cylinder is hella low, bummer man. __________________ M4CS Frozen Blue ARM DP's/Resonated Mid-pipe \| SPL links \| Hotchkis bars \| JRZ RS2/camber plates \| K&N \| Koyorad HX \| Powerflex purple \| Rouge \| Spiegler \| Speed Eng. snorkel \| Vargas CBC/hub \| Wagner IC \| xHP \| Xpel stealth ppf
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11-20-2022, 09:10 PM	#17
JAI///M3 Lieutenant 528 Rep 502 Posts Drives: F80 M3 Join Date: Dec 2021 Location: East Bay iTrader: (0) Garage List 2018 F80 [0.00]	Assuming the photos are in order, cylinders 3 and 6 look to be around #105 where the rest are closer to #120-130. It's not like they're dead cylinders but higher deviation than I would like Was the engine warm when you did the test?
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11-21-2022, 07:24 AM	#19
Tymula_81 Second Lieutenant 87 Rep 234 Posts Drives: F10 528 xdrive Join Date: Dec 2016 Location: Bronx ny iTrader: (0)	Hey Here is my log https://www.bootmod3.net/log?id=637b...90c6a3cbb67255
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11-21-2022, 07:40 AM	#20
TopJimmy Major General 5445 Rep 5,137 Posts Drives: 2023 M3 Comp xDrive Join Date: Jul 2019 Location: Chester County, PA iTrader: (5)	You don't get a good picture in 6th gear at low RPMs. The log needs to be a 4th gear pull from 3K up to 6500, with DCT fully off, in Sport+ mode. Make sure you get both WGDC and the LPFP added to the logging. __________________ '18 F80 Base 6MT \| '19 F82 Exec DCT \| '18 F82 Comp Exec DCT \| '23 G80cx
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