[chadillac2000]

A little backstory:

Went from stock to FBO (BMS DPs - VRSF 7" FMIC - BMS JB4 G5 ISO - BMS E85 BEF - Fuel It Stage 2 LPFP - MMP Silicone Inlets - BMS DCI - ER Charge Pipe - HKS BOV) over the course of about 1 month. Everything was running great, until one evening I up the E85 mixture and switch to Map 2 on my BEF (targets 17 psi). Injectors, plugs have been replaced very recently. Started my 1 hour commute to work, and with about 15 minutes left found some room to go WOT. At the top of 3rd gear, get a 29D2 misfire in cylinder 6 and started running rough. No problem, it's probably the coils, so I limped it to work.

At the end of the day, gently made the commute back home. About halfway home the car started missing even at normal throttle, and by the time I was pulling into the parking lot at home, car was throwing check engine light at any RPM. Even at idle, car was stumbling and running awful. Turned the car off and left it sitting for 2 days until my 6 new coils arrived, had planned on changing these soon for preventative maintenance this week anyways.

Replaced all 6 coils, no change. Still misfire on cylinder 6. Had a new plug on hand, so stuck a brand new plug in cylinder 6, no change, still misfire on cylinder 6. Here's a picture of the original plug in cylinder 6 with around 1,000 miles of easy use. Looks fine with no signs of anything funny going on.



Checked all vacuum hoses, injector connections, etc. and everything is secured and plugged in like it should. At this point, the only thing remaining would be a faulty injector, which I had originally ruled out because the previous owner had just had them replaced under recall somewhat recently.

Go check them and sure enough, cylinder 1, 2, 3, and 5 have 08 index injectors, while cylinders 4 and 6 (the faulty cylinder) have 07 index injectors. Makes me think only 1, 2, 3, and 5 have been upgraded, and 4/6 are the original injectors.

My question at this point, does it sound right that I would have virtually no issues out of an injector and then all of a sudden it fail completely? My car at idle is/sounds like it's running on 5 cylinders at all time. My previous car had injector problems and it resulted in a rough idle on cold starts, but this engine doesn't seem to be "hunting" idle RPM like that, and it in no way gets better after the engine has heated up.

After letting the engine run like in the video for a minute or two, I pull the plug and it looks exactly the same as before, which sounds to me like the injector is not the problem, or it's failed completely and is no longer moving any amount of fuel. Would love to hear some input before I bite the bullet and just swap all new index 12s in there. I would have swapped the injectors today, but would hate to have to deal with seals if I swapped injectors 5 and 6, and the misfire again stayed on 6. Again, this rough running condition is across the board, all RPMS, idle, partial throttle, etc. Going WOT is not even an option as rough as it's running.

Video of the car running poorly: https://www.youtube.com/watch?v=ELfDJqM6XcY

[CanadianTSi]

Probably 95% chance its a bad injector or injector seal. You could always buy a single used injector that is less than an index 11 and swap it in or as you said spring for all new 12s

[CanadianTSi]

Also index 8s are at least 2-3 years (if not more) old, so the PO may have a different definition of "somewhat recently"

[sk55]

Originally Posted by chadillac2000

A little backstory:

Went from stock to FBO (BMS DPs - VRSF 7" FMIC - BMS JB4 G5 ISO - BMS E85 BEF - Fuel It Stage 2 LPFP - MMP Silicone Inlets - BMS DCI - ER Charge Pipe - HKS BOV) over the course of about 1 month. Everything was running great, until one evening I up the E85 mixture and switch to Map 2 on my BEF (targets 17 psi). Injectors, plugs have been replaced very recently. Started my 1 hour commute to work, and with about 15 minutes left found some room to go WOT. At the top of 3rd gear, get a 29D2 misfire in cylinder 6 and started running rough. No problem, it's probably the coils, so I limped it to work.

At the end of the day, gently made the commute back home. About halfway home the car started missing even at normal throttle, and by the time I was pulling into the parking lot at home, car was throwing check engine light at any RPM. Even at idle, car was stumbling and running awful. Turned the car off and left it sitting for 2 days until my 6 new coils arrived, had planned on changing these soon for preventative maintenance this week anyways.

Replaced all 6 coils, no change. Still misfire on cylinder 6. Had a new plug on hand, so stuck a brand new plug in cylinder 6, no change, still misfire on cylinder 6. Here's a picture of the original plug in cylinder 6 with around 1,000 miles of easy use. Looks fine with no signs of anything funny going on.



Checked all vacuum hoses, injector connections, etc. and everything is secured and plugged in like it should. At this point, the only thing remaining would be a faulty injector, which I had originally ruled out because the previous owner had just had them replaced under recall somewhat recently.

Go check them and sure enough, cylinder 1, 2, 3, and 5 have 08 index injectors, while cylinders 4 and 6 (the faulty cylinder) have 07 index injectors. Makes me think only 1, 2, 3, and 5 have been upgraded, and 4/6 are the original injectors.





My question at this point, does it sound right that I would have virtually no issues out of an injector and then all of a sudden it fail completely? My car at idle is/sounds like it's running on 5 cylinders at all time. My previous car had injector problems and it resulted in a rough idle on cold starts, but this engine doesn't seem to be "hunting" idle RPM like that, and it in no way gets better after the engine has heated up.

After letting the engine run like in the video for a minute or two, I pull the plug and it looks exactly the same as before, which sounds to me like the injector is not the problem, or it's failed completely and is no longer moving any amount of fuel. Would love to hear some input before I bite the bullet and just swap all new index 12s in there. I would have swapped the injectors today, but would hate to have to deal with seals if I swapped injectors 5 and 6, and the misfire again stayed on 6. Again, this rough running condition is across the board, all RPMS, idle, partial throttle, etc. Going WOT is not even an option as rough as it's running.

Video of the car running poorly: https://www.youtube.com/watch?v=ELfDJqM6XcY

lower the boost to 14 psi... do a pull from 2k-7k... see if u get a misfire?

are u 6 MT?

[muncie21]

Originally Posted by CanadianTSi

Probably 95% chance its a bad injector or injector seal. You could always buy a single used injector that is less than an index 11 and swap it in or as you said spring for all new 12s

After that I'd start looking to replace/check the mosfets

[chadillac2000]

Originally Posted by CanadianTSi

Probably 95% chance its a bad injector or injector seal. You could always buy a single used injector that is less than an index 11 and swap it in or as you said spring for all new 12s

Originally Posted by CanadianTSi

Also index 8s are at least 2-3 years (if not more) old, so the PO may have a different definition of "somewhat recently"

Agreed. About to pull the trigger on index 12s so I don't have to worry about others going bad in the future. I've seen too many issues arise from a leaky fuel injector causing more serious issues than just misfires to take the chance.

Originally Posted by sk55

lower the boost to 14 psi... do a pull from 2k-7k... see if u get a misfire?

are u 6 MT?

Yes I'm a 6MT. Changing maps won't help at all, I get a misfire as soon as the car is started. Stumbling, running on 5 cylinders. Just going through the RPMS in 1st, 2nd and 3rd is a struggle as it sputters and hesitates the whole way. Going WOT on a tuned map is out of the question, so it's not a matter of lowering the boost.

Originally Posted by muncie21

After that I'd start looking to replace/check the mosfets

Not throwing any of the codes associated with mosfets, and I've also only heard of this on 07s -- I have a late build 08.

[335_E90]

i had the exact same problem on my 09 335 but on cyl 4 and it was my injector that was missing the stupid clip due to the garage being incompetant.....took the clip off my old injector and put it on the new one and everything is now perfect.

[Andym3100k]

Originally Posted by 335_E90

i had the exact same problem on my 09 335 but on cyl 4 and it was my injector that was missing the stupid clip due to the garage being incompetant.....took the clip off my old injector and put it on the new one and everything is now perfect.

Which clip are you referring to? I got a misfired on 5 & 6 too but after changing plug, coil & injector it is still there. I'm running 28psi on hybrid with plug gap at 0.018 bank 1 afr look good but bank 2 afr run quite lean 13+.

[limitdown]

Originally Posted by Andym3100k

Which clip are you referring to? I got a misfired on 5 & 6 too but after changing plug, coil & injector it is still there. I'm running 28psi on hybrid with plug gap at 0.018 bank 1 afr look good but bank 2 afr run quite lean 13+.

There have been reports of shops forgetting to install/reinstall the decoupling element.
Another thing that could be causing your misfire is a broken Bank2 pre-coat oxygen sensor. I've replaced mine twice in 50k miles.

[marconi118]

do you have meth limitdown?

it seems meth can damage o2 sensor quickly

[Andym3100k]

Originally Posted by limitdown

There have been reports of shops forgetting to install/reinstall the decoupling element.
Another thing that could be causing your misfire is a broken Bank2 pre-coat oxygen sensor. I've replaced mine twice in 50k miles.

Just change both my o2 sensor pre-cat, waiting to test out after putting in the 6 clips. I heard the clips are not there for the old injectors? Only the newer index injectors comes with it? Anyone out there with older ones can verify? Thanks

[335_E90]

Originally Posted by Andym3100k

Just change both my o2 sensor pre-cat, waiting to test out after putting in the 6 clips. I heard the clips are not there for the old injectors? Only the newer index injectors comes with it? Anyone out there with older ones can verify? Thanks

i had index 7 and 8 before and they all had the decoupling clips....when the garage installed my new injector on cyl 4 (index 12) there was no decoupler installed so i used the one from my old injector and now its been perfect ever since! hopefully this solves your issue....look at the picture a few posts up to see a pic of decoupler.

[Andym3100k]

Originally Posted by marconi118

do you have meth limitdown?

it seems meth can damage o2 sensor quickly

Oh yes I hv meth n spraying 100%, there isn't any cel light on o2 sensor. Tonight will try out after putting in 6 extras clip spacers. Actually just realised the existing clips r all there with index 8 injectors, now I'm putting double clips to see whether it helps.

[chadillac2000]

For those wondering...6 new index 12 injectors have seemed to do the trick. After coding them up, hit the start button and everything sounded much better than before. Idle is dead on the money and I'm back up on 6 cylinders again.

Cover off



Fuel lines removed



Where I kept everything for the install organized. Recorded all the values so I could code the injectors afterwards with INPA.



Not sure if the fact that cylinder 6 was giving me the trouble had anything to do with it, but the cylinder 6 injector was 10x as hard as the other 5 to remove. Had no issues at all getting 1-5 out, but 6 took forever. 1-5 looked pretty normal to me, but 6 did have some visible issues going on.





All buttoned back up. Also threw in some BMS cowl filters and a RB PVC valve while I had everything off for the injector swap.



And the after video: https://www.youtube.com/watch?v=96JxLc7ynyI

[vasillalov]

Why 6 new injectors? You have an injector issue on cyl 6. You correctly eliminated spark plug and coil as issues. What's left is the fuel injector. ...so replace only one, not all 6.

[CanadianTSi]

Originally Posted by vasillalov

Why 6 new injectors? You have an injector issue on cyl 6. You correctly eliminated spark plug and coil as issues. What's left is the fuel injector. ...so replace only one, not all 6.

Guess it depends on how much you want to spend but with new injectors you have to do an entire bank anyways so alot of people just do them all. Personally a used $40 injector solved all my problems.

[vasillalov]

Originally Posted by CanadianTSi

Guess it depends on how much you want to spend but with new injectors you have to do an entire bank anyways so alot of people just do them all. Personally a used $40 injector solved all my problems.

Not true. You can mix and match injector revisions in the same bank. I am the first one who did it and I am still driving around with mixed injectors. No issues at all.

[Jeff@TopGearSolutions]

It's best practice to replace in banks at a minimum. I too only had 2 bad injectors but replaced all 6 for peace of mind knowing that each cylinder is running optimally fuel wise. If you're on a tight budget and 1 would solve the apparent issue it's understandable.

[chadillac2000]

Originally Posted by Jeff@TopGearSolutions

It's best practice to replace in banks at a minimum. I too only had 2 bad injectors but replaced all 6 for peace of mind knowing that each cylinder is running optimally fuel wise. If you're on a tight budget and 1 would solve the apparent issue it's understandable.

This ^^^^^

Not trying to deal with misfires anytime in the near future. Too much hassle, headache. I can rest a little bit easier knowing I have brand new plugs, coils, and injectors in there. Again, obviously not budget friendly.

[Jeff@TopGearSolutions]

Originally Posted by chadillac2000

This ^^^^^

Not trying to deal with misfires anytime in the near future. Too much hassle, headache. I can rest a little bit easier knowing I have brand new plugs, coils, and injectors in there. Again, obviously not budget friendly.

Yep, I did the same thing. Did spark plugs coils and fuel injectors all at once. Didn't feel like playing the guessing game and I like my vehicles running optimally.

[feuer]

Originally Posted by chadillac2000

This ^^^^^

Not trying to deal with misfires anytime in the near future. Too much hassle, headache. I can rest a little bit easier knowing I have brand new plugs, coils, and injectors in there. Again, obviously not budget friendly.

Rest a little bit? What a joke! You have BMW with n54. You should have donate the money instead. Or at least buying Vasil a cold drink as a thank you for teaching us all how to code injectors at home.

[feuer]

Originally Posted by CanadianTSi

Also index 8s are at least 2-3 years (if not more) old, so the PO may have a different definition of "somewhat recently"

Index 12 are at least 3 years old. I installed them in early 2013. Vasil I think discovered them in 2012. I had index 9 changed during recall campaign at dealer in 2010. These cars are 10 years old.