[tricky_bmw]

Hi everyone

I have a 2008 325i 2996cc E90 64K miles

I have recently developed a misfire (on 4 and 5 and sometimes 6) and took it to my local BMW specialist (not dealer) and they diagnosed it as an issue within the diaphram on the valve cover. It actually transpired that the valve cover was cracked and needed replacing ...£700+ spent

This however did not stop the misfiring from happening. The engine running has improved and the misfire of 6 is not been seen recently

I have recently replaced the plugs and changed one of the ignition coils and removed the others around to see if it is was the coils and again no joy.

I suspected that it therefore could be the injectors or the pre cat sensor.

I have been using a reader and inCarDoc and can see that the short term fuel trim between the 2 banks is widely different and for bank 2 the sensor is suggesting it is getting too much fuel (assuming -ve is saying give less petrol) and thus causing the misfire.


I was hoping you experts would help confirm this !

The misfire only happens when the car is cold and I get an engine light and it goes into open loop.
If I stop the car and restart then generally this clears it and I am good to go but the fuel trim still shows bank 2 is still too rich.

attached is the graph I captured from inCarDoc. Line in green is bank 2

If I do need to change the injectors can someone let me know the part number and best (cheap) please to get them. Am I also right in saying you should not use second hand one without the ring at the bottom being replaced?

[relative4]

Attachment is no good. What are the long-term fuel trims at idle, 2500, and 4000?

[N52bigblock]

Originally Posted by tricky_bmw

Hi everyone

I have a 2008 325i 2996cc E90 64K miles

I have recently developed a misfire (on 4 and 5 and sometimes 6) and took it to my local BMW specialist (not dealer) and they diagnosed it as an issue within the diaphram on the valve cover. It actually transpired that the valve cover was cracked and needed replacing ...£700+ spent

This however did not stop the misfiring from happening. The engine running has improved and the misfire of 6 is not been seen recently

I have recently replaced the plugs and changed one of the ignition coils and removed the others around to see if it is was the coils and again no joy.

I suspected that it therefore could be the injectors or the pre cat sensor.

I have been using a reader and inCarDoc and can see that the short term fuel trim between the 2 banks is widely different and for bank 2 the sensor is suggesting it is getting too much fuel (assuming -ve is saying give less petrol) and thus causing the misfire.


I was hoping you experts would help confirm this !

The misfire only happens when the car is cold and I get an engine light and it goes into open loop.
If I stop the car and restart then generally this clears it and I am good to go but the fuel trim still shows bank 2 is still too rich.

attached is the graph I captured from inCarDoc. Line in green is bank 2

If I do need to change the injectors can someone let me know the part number and best (cheap) please to get them. Am I also right in saying you should not use second hand one without the ring at the bottom being replaced?

What engine do you have in your car N52K or N53? If you have the N53 it will almost certainly be your injectors.

[lxrdvbz]

here in Italy if you took your bmw to a bmw specialist it will costs more than a lung the black market and they will solve you nothing at all. I feel you, and I'm so sorry for you boy.

[tricky_bmw]

Hi
Sorry for the delay in responding
I have the N53
When looking at the long term fuel trims.... initially these read 0
On increasing the revs to 2500 and then 4000 they remained at 0
However when returning to idle bank 1 showed -1.56 and bank 2 showed -9.38%

I have got INPA up and running (though very novice at it so far) .

Any help would be appreciated?

[ctuna]

diagnostic manual ista/inpa
https://bimmerprofs.com/diagnostics-inpa-part-1/
https://www.google.com/url?sa=t&rct=...xo19teM9vkTF-C
https://www.google.com/url?sa=t&rct=...7x8H3pN8h1fMuF
https://www.bimmerforums.com/forum/s...-P-actually-do

Inpa link's may help.