Very slight misfire with no CEL or SES light w/ video

[Tlandreth22]

Hey guys, several hours ago I was heading back to my apartment from class, and I noticed very slight pop coming from under the hood. Upon checking under the hood, I found that it was a misfire, but there is no service or CEL and it is idling fine as well. Any guesses?

I have a video loading on youtube, and I'll post it as it is completed.

http://youtu.be/L1PfpIy1FAc

[danewilson77]

Even though there is no light, you still may be able to read a stored code.



Sent from my S4 > Mason, OH

[330i ZHP]

+1

[Tlandreth22]

So after reading the codes, the following were issues: 1. misfire due to low fuel 2. P0171 too lean- bank 1, and 3. P0174 too lean- bank 2.

I decided to inspect the vacuum hoses, and found a decent sized hole in the upper intake boot. The popping was from the coil popping against the valve cover on cylinder 3. The head of the spark plug was stuck in the coil while the plug itself remained in the cylinder. Upon changing out the Bosch plugs with new Bosch plugs, the following codes were read:

1. P1343 misfire cylinder 1 with fuel cut-off
2. P1344 misfire during start cylinder 2
3. P1346 misfire during start cylinder 3
4. P1350 misfire during start cylinder 5
5. P1352 misfire during start cylinder 6
6. P0171 system too lean- bank 1 due to large vacuum leak
7. P0174 system too lean- bank 2 due to large vacuum leak

I cannot replace my ripped upper intake boot until my dealership opens Monday. My question is, are the misfires during start due to the Bosch plugs? Has anyone had any problems like this?
7.


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[330i ZHP]

The stock plugs are NGK (3199) BKR6EQUP

I would say eliminate the vacuum leak and see if the other problems go away. It is weird the became worse after plugs, check your coils to insure fully seated. Check the ground on the coil harness.

[echo46]

Agree, replace the intake boot and see if situation resolves. Read codes and report back.

[BCS_ZHP]

So after reading the codes, the following were issues: 1. misfire due to low fuel 2. P0171 too lean- bank 1, and 3. P0174 too lean- bank 2.

I decided to inspect the vacuum hoses, and found a decent sized hole in the upper intake boot. The popping was from the coil popping against the valve cover on cylinder 3. The head of the spark plug was stuck in the coil while the plug itself remained in the cylinder. Upon changing out the Bosch plugs with new Bosch plugs, the following codes were read:

1. P1343 misfire cylinder 1 with fuel cut-off
2. P1344 misfire during start cylinder 2
3. P1346 misfire during start cylinder 3
4. P1350 misfire during start cylinder 5
5. P1352 misfire during start cylinder 6
6. P0171 system too lean- bank 1 due to large vacuum leak
7. P0174 system too lean- bank 2 due to large vacuum leak

I cannot replace my ripped upper intake boot until my dealership opens Monday. My question is, are the misfires during start due to the Bosch plugs? Has anyone had any problems like this?
7.


Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)

For that ripped intake boot, & considering its Sunday, use some duct tape or other strong tape to try to cover the hole in the boot for today. Doesn't have to be pretty, just functional, that might decrease the vacuum leak enough so you don't get P0171 & P0174.

[danewilson77]

For that ripped intake boot, & considering its Sunday, use some duct tape or other strong tape to try to cover the hole in the boot for today. Doesn't have to be pretty, just functional, that might decrease the vacuum leak enough so you don't get P0171 & P0174.

+1

Have done this before.

Sent from my S4 > Mason, OH

[Tlandreth22]

The intake boot was patched this morning, and the misfire due to low fuel code went away, however banks 1 and 2 are still too lean. As for the plugs and misfires, they are only detected on start up, and even then the car idles fine. Planning to put NGK plugs in this afternoon, my Indy said that should resolve the problem of the misfires.


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[danewilson77]

The intake boot was patched this morning, and the misfire due to low fuel code went away, however banks 1 and 2 are still too lean. As for the plugs and misfires, they are only detected on start up, and even then the car idles fine. Planning to put NGK plugs in this afternoon, my Indy said that should resolve the problem of the misfires.


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BKR6EQUP FTW :)

Sent from my S4 > Mason, OH

[echo46]

Did it resolve the issue?

[Tlandreth22]

Thanks for all of the info and help on diagnosing my problem. Plugs were the issue for the misfires, and now there are no error codes for misfiring. Now the only thing left to do is replace the upper intake boot that has been patched for now, however it is throwing a code for Bank 2 being too lean (P0174) which is due to the vacuum leak. Hopefully it will be resolved tomorrow after I replace the torn boot.

Again, I appreciate everyone's help! It's a privilege to be in the Mafia.


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[LivesNearCostco]

Check small elbow on lower boot too. If it's same age as upper boot, good chance it also has a tear.

[wertyu78]

Told you it was the plugs ;). You can't go wrong with the NGK's. Did you end up getting a 1 piece intake boot for X3 3.0 like I mentioned? I paid $43 for mine and it's been great. Perfect fitment.


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