[abivanshreddy04@gmail.com]

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.

[Mrmigs2011]

Originally Posted by suspect

Thanks Mrmigs2011. I would expect LTFT to be pretty much zero like yours are. Do you have a log at idle (600-700rpm) too that you could upload?

https://datazap.me/u/mrmigs2011/idle-logging?log=0&data=3-21

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.

[suspect]

Originally Posted by Mrmigs2011

I'll get on that today for you, mine has been a little more stumbling again as of recent.

Another thing I've noticed is, try hold your revs at 1200-2000 rpm, go up in 100 rpm increments, my car won't hold a steady throttle at low revs and can hear the missing.

If I push the clutch in its even worse, I think that's starting to spool turbo lightly.

I can also hear wastegates (old and worn) not able to stick to one position.

Best idle I ever had was at 1.1mm spark gap, but too wide for this turbo engine for sure.

Another huge thing I've noticed,

Ambient temp...all the time is changing how often the stumbles are. In the rain more then the warm, something on the intake side perhaps, I need to pressure test the system again..

My car wont hold steady revs at around 3000 RPM, at 3000 RPM it would oscillate by maybe 200 RPM. I have seen this on another car where it was a faulty idle control valve. Does this engine have a idle control valve? This also could be a vacuum leak.

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.

Originally Posted by Mrmigs2011

https://datazap.me/u/mrmigs2011/idle-logging?log=0&data=3-21

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.

No problem. Thanks for the log. I just did a proper MHD log will upload it later but my timing is also jumpy. I am not sure what to think I have not been able to find many other idle logs. I did not log VANOS though. How do you get ltft and timing correction for each cylinder? I dont see these options on MHD.

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

[suspect]

Originally Posted by studio54

Missed that message ! weird that higher rpm idling made things worst
On mine, higher idle equals less stumbles.

Do you have also stumbles when cruising at very low rpm (or outside idle) or just idle ?

No news?

To my understanding there aren't too many possibilities, I would guess it's either a plug not igniting correctly, either a leaking injector dripping one drip of fuel or something, resulting in a small pop/explosion in the exhaust for both scenario. Mrmigs2011 also said it could be a very small vacuum leak ? According my last measures, my idle inHg values seems normal and it appears too random to me to be a vacuum leak.

I also need to figure that on mine and since I have to change plugs, I will start by this in november, I will also check at the same time if one or some of the old ones are wet cause thoses small stumbles (+ natural burbles on let off but I have the PE exhaust) always made be believed I've had a slight leaky injector since I have this car.

I have not noticed any stumbles when cruising or under any load.

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?

[san40k]

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.

[suspect]

Originally Posted by san40k

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.

I double checked it and the numbers are correct. Tried to enter the injector numbers again and car behaves the same.

[studio54]

Originally Posted by suspect

I have not noticed any stumbles when cruising or under any load.

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?

I replaced my spark plugs with NGK (gapped the best I can do more or less at 0.022) and since I had my MOT with the emission test, while waiting I let idle the car a long time, and didn't felt or hear any hiccup at 650 rpm idle so that's fine, but that's maybe because spark plugs are brand new. I will update later if it comes back.

Old spark plugs were worn and a bit brownish but all dry, all same color.

[Mrmigs2011]

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.

[suspect]

Originally Posted by Mrmigs2011

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.

I hadn’t heard the car pop again so left it as is. Idle is still the same. Although after doing OFHG I have introduced some vacuum leak which causes random 30ff shadow code but 90% of the time meets boost fine.

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.

[studio54]

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... )

[N54_carlos818]

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