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BMW 3-Series (E90 E92) Forum
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N54 hiccups tiny misfires? idle not smooth
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10-19-2023, 08:15 PM | #23 |
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Help! Cylinder 6 misfire
Hi, I had a misfire and pulled the codes using Bavarian technic. I had a Cylinder 6 misfire due to low fuel level. Fuel was fairly low at 100 km range to spare. Clearing the code and filling did not help. Before all of this I used to have a crankshaft position sensor code that just disappeared so I didn't bother to replace it. It keeps misfiring at around 3,500ish rpms in any gear, It does not misfire at any other rpms. I have swapped my plugs and coiils and used injector cleaner but didn't help. After cleaning all the codes, I got cylinder 6 misfire code but this time it was paired with Lamda probe behind catalytic converter 2 at the same exact time. No tune and replaced spark plugs 10k km ago. I should mention, there is ticking noise from the engine at around 3k rpms as well when cold.
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10-19-2023, 11:46 PM | #24 | |
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Sorry suspect, took me ages to figure out how to manually log believe it or not, on observation it looks like my exhaust vanos is unsettled Vs intake vanos, Some small deviation in boost vacuum according to the system so need to get the manual guage plummed in and check my vac lines aren't collapsing (cars been acting real blocky on throttle lately) And I'm still not happy with the engines timing at idle. Surely it shouldn't be all over like it is, people saying idle timing is normal for emission purposes but I can't believe a lean burning motor would bob around with cylinder timing like that so further research is required here. |
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11-03-2023, 11:38 AM | #25 | ||
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I have not tried 1200-2000 RPM but there is a wastegate rattle. The rattle goes away at around 1700 RPM which is when the wastegates fully closed I think. Quote:
Also I noticed that both my bank LTFT are negative like yours at idle but bank 2 is more negative than the other by about 3%. Idle https://datazap.me/u/suspected/idle1...&data=16-17-18 Last edited by suspect; 11-03-2023 at 07:12 PM.. |
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11-03-2023, 11:44 AM | #26 | |
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I changed one of the injectors to a new one in bank 2 and now my LTFT is even more negative! I looked at the MAP values with engine on and off. Engine off was ~14 psi and engine on was 4-5 psi which is normal so I dont know if to think this is a vacuum leak. Did you find any wet plugs? |
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11-04-2023, 02:57 PM | #27 |
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Double check your injector calibration in inpa, especially for recently replaced one.
I have seen "rough running" after replacing injectors and improperly coding them first.. went away after re-coding. |
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11-06-2023, 05:59 AM | #28 |
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I double checked it and the numbers are correct. Tried to enter the injector numbers again and car behaves the same.
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12-01-2023, 05:17 AM | #29 | |
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Old spark plugs were worn and a bit brownish but all dry, all same color.
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beter laat dan nooit
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05-22-2024, 01:27 AM | #30 |
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Bumping this up again.
How are peoples cars doing? Cycle is repeating again for me after a relatively few good months with it. Heavy downpour today and its evident the motors not happy again. Heard timing chain rattle on start the other day, wonder if the 18 year old tensioner is giving out as the drive from cold is blocky as hell. Things to now check: Chain tensioner Wallnut again perhaps Vanos solenoids (also probably 18 year old) Bearing ledges Vanos pulse wheels Vanos actuators? Mosfet testing? Another plug check for injector leaks. Ahh these motors are great when their happy, annoying when not. I suspect im still on the original turbos at 130k miles though. The wastegate rattle is huge but their still delivering 18 psi with my temporary fixes. I wonder if wastegate failure could result in boost being passed through at higher levels during low load/idle condition. |
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05-22-2024, 07:45 AM | #31 | |
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Why do you think it’s the chain? What do you mean “blocky”? Did you leave the car parked for long? If engine isn’t started for long majority of the oil drips down and then the top end of the engine runs dry and you hear a harder start and a bit of rattle. |
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05-30-2024, 02:05 AM | #32 |
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4 months later here, the thing is that I didn't drive a lot, so my spark plugs are probably still like new and idle is globally ok but I think I noticed a tiny hiccup or two felt in the cabin while idling (anecdotally, not every 30-40 seconds like before).
I will see if frequency get worse over time. My theory is that maybe with a slight injector leak, brand new spark plugs are masking the problem temporarily (but sometimes I just want to believe that it's just the nature of this engine to have these kind of tiny hiccups... )
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06-02-2024, 11:43 AM | #33 |
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I recently got a code mp0303 on my 2008 335xi change the spark plugs about to change ignition coils I already did soo for cylinder 3 and it already runs way better but from scanning it at an autozone and switching spark plugs my check engine light finally came on , next step is to clean and test my fuel injectors!! anyone have any feedback I can post pictures and detailed description on codes!! I’m a new rookie diy bmw owner please be patient
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