07-01-2019, 12:29 PM | #1 |
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Misfire but no CEL
I’m having issues with my 2015 bmw m4 with 85k miles. On idle and acceleration the car is very sluggish and it hesitates. I’m trying to gauge if the injectors are going bad or it the coils. My car is tuned and the spark plugs were changed 5k miles ago.
Here is a clip of my car at idle: https://streamable.com/x7l5z |
07-01-2019, 01:59 PM | #2 |
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Did you check the Top Mount Inter cooler Reservoir? If it is empty then it has an internal leak going into your exhaust manifold which got coolant all over the place causing the misfire. Don't ask me how I know this to be possible
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07-01-2019, 04:26 PM | #3 |
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that is definitely fuel or spark. I would think you would get some codes.
my coils were starting to miss at high boost/rpm at 30k miles. I replaced them with new OEM coils.
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07-03-2019, 12:18 PM | #4 | |
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No codes which was the weird part. My friend and I changed the coils on the car and it was still misfiring, so we put the old coils back in and the issue stopped. It was so strange, I just took the car to bmw for diagnosis. |
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07-03-2023, 02:49 PM | #6 |
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I'm having a misfire issue as well, this time with no check engine lights. It only happens when at full or almost full throttle, otherwise I can cruise fine. I have astage 2 catless 2015 f83 m4 82k miles, alternating between full e85 tune and 93 gas from RK-Tunes.
This started after having my plugs (Ngk F8S flex fuel plugs gapped 0.022 and valve cover gasket replaced, mechanic thought it were bad coils, installed 6x Dinan coils, still misfired. Misfire CELS saying cylinder 5. Replaced injector 5, still misfired under load. Requested new plugs to be installed again Ngk 97506 gapped 0.22. Misfires are fixed. A month later misfires happens again!!! Around 4-5k rpms heavy misfires, sputtering and jerking, but now there are no check engine lights and the car drives fine after I let off throttle. I changed the spark plugs again for the 3rd time, and misfires. ** **When on 93 octane tune, the misfire happens intermittently at high rpm and full throttle, but still there. On e85 its always misfiring hard under full throttle. Can anyone point me in the right direction before I spend more money =/ |
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07-05-2023, 01:44 PM | #7 |
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I had something similar happen and my intercooler was leaking. Would run fine when cruising then as soon as I got on the throttle it would bog down. J pipe gets filled with coolant then it gets sucked in or pushed under load.
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07-23-2023, 06:06 PM | #8 | |
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Picture of reservoir June 5th, pretty low, but then I filled it to the hole . Reservoir July 23rd, it looks like its down again?? Does this confirm my CTS TMIC is leaking again? not even 30k miles on this intercooler, I wonder how their warranty is? |
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07-23-2023, 06:24 PM | #9 | |
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07-24-2023, 10:45 AM | #10 |
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That small of a difference could just be a bubble in the system unless you did the correct procedure and double checked right after.
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07-24-2023, 12:05 PM | #11 |
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10-14-2023, 12:51 AM | #12 |
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RESOLVED!!! Misfires at high RPM under full throttle with no CODES were happening a few weeks after installing new F8S plugs 0.022 gap, Dinan coils, and replacing new valve cover. I didn't want to believe those new items were bad, so I thought the TMIC was leaking.
These stupid Dinan coil packs were the cause of my misfires!! Installed Delphi coil packs and my car is smooth again! Don't fall for the "10% more output" claim for the Dinan coils, they are trash!! |
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