[GeorgiaTech335coupe]

I also had an incompetent dealer with my cold start misfires. they replaced all injectors, still there, I replaced all plugs, still there, I seafoamed, still there, I brought my car a total of 5 times into the dealer and their "master tech" with 20+ years couldnt figure it out. Then I resetted all my adaptation values with a GT1 and poof, no more cold start misfires. This might be a viable option for you, but I cannot gaurantee anything.

[RFGuy_KCCO]

These mysterious misfire issues sound just like the issues that guys over on the VW MKV forums see on their 2.0T motors (I just sold my 2006 GTI to get my 335i). It turns out, most of these issues are being caused by filthy, carbon-fouled intake valves on the direct injection motors.

As most of you probably know, on any direct injection motor with a legal PCV system in place, oil blow-by builds up on the intake valves because they are not washed with fuel - like they would in a port injection motor. This build-up can get very bad in a very short period of time, depending on many factors. In any case, this build-up can get so bad that it actually prevents the valves from fully seating properly, causing misfires. Since the N54 (and my N55) are direct injection motors, I would bet the misfire issues many of you are seeing are actually caused by very dirty intake valves.

Oh, by the way, while Seafoam in the intake is great if used regularly from brand new, it is utterly worthless once this gunk builds up on the valves. One guy with a 2.0T took his intake manifold off to physically scrub his valves. It took him hours of work with many strong solvents, dental picks, q-tips, toothbrushes, etc. before he even began to get all of the valves completely clean. There is no way that sucking up some Seafoam into the intake is going to clean that kind of build-up. I plan to use it every 5,000 miles, just as I did on my GTI - in which I had no misfire issues in over 4 years of ownership.

[rbaldwin28]

Originally Posted by joec500

I am in the exact same boat, are you 2007 MSD80?

But I am 6MT

Yea, he is 2007 MSD80 same as me. You are the first person I have seen with a 6MT though. Are you tuned? Procede or JB?

[rbaldwin28]

Originally Posted by maui86

try seafoam or something that would show any possible exhaust leaks near the o2 sensors.

i have idle vibration and light throttle/boost misfires(but not enough to throw codes). i can see lean spiking happening. i replaced the o2's...didn't work...then i seafoamed and found an exhaust leak at the vband. under idle and light throttle i'm pretty sure air can get sucked in and fool the o2 sensors its running lean.

question though to the experts...if the ecu is being told its getting extreme lean conditions, does it automatically shoot more fuel to compensate? to me, this makes sense to do, but if the engine isn't really running lean and now the engine(or one bank) is too rich, could that cause misfires? it could explain the vibrations. i ask this because the bank(2) with the leak, the o2 sensors were covered in soot. yet bank1 wasn't.

i'm waiting for the vband clamp to arrive so i can replace all the gaskets and clamps to have no reason for a leak.

teri

Good point, I hadn't thought of that but it seems possible. I only see cylinder 6 miss fire 99% of the time but I suppose there could be subtle differences causing that cylinder to miss fire the most when running rich. I will check this out when I get my car back. Thanks for the idea.

[maui86]

Originally Posted by rbaldwin28

Good point, I hadn't thought of that but it seems possible. I only see cylinder 6 miss fire 99% of the time but I suppose there could be subtle differences causing that cylinder to miss fire the most when running rich. I will check this out when I get my car back. Thanks for the idea.

no problem! i figured it could be a shot in the dark! :-) just can't wait for the clamp to come in so i can finally stop the leak :-)

[marconi118]

Originally Posted by maui86

try seafoam or something that would show any possible exhaust leaks near the o2 sensors.

i have idle vibration and light throttle/boost misfires(but not enough to throw codes).
teri

I have the same, idle vibration + light misfires without codes.

6MT, MSD80, 07/07, new HPFP and ISTAP 34 have already seafoamed to clean the valves, but have to try again to see if there is a leak.

But as stated by teri, if it sucks in air the o2 will read lean, and the DME will compensate, so the bank will run rich. Can this produce the idle vibrations???

[rismo]

I have had the same, at the end they replaced my DME. That solved the issue, although that might have been more to due with adapation then a physical broken DME.

[Wiredless]

Have the same issues more or less, mine is Build 10/07 and 6MT.

Funny that most of the guys here are in Belgium. What fuel do you guys use?

I tend to think it is also linked to carbon buildup...short daily commuting distances could play a role.

[marconi118]

my idle vibration and light misfire at partial throttle mid rpm (2500) started right after dealer changed all my 6 injectors and cleared adaptations.


So it is for sure related to the defective new injectors and NOT from carbon build-up and HPFP

[ETS Michael]

Originally Posted by marconi118

I don't want to change the car to get a N55!

I have got the same, light misfire at 50% throttle 2500rpm. Unfortunately for me it is so light that the DME don't record any fault code.
So I don't even know witch cylinder it is
I really suppose that the misfire is caused by lean A/F (engine goes lean burn mode at light throttle, only at WOT the power kit acts...)
Try to replace injector of cyl6 again!

I have this exact same problem. The problem is so light that it's not throwing a code and the dealership is saying they can't do anything unless it throws a code. They are keeping the car overnight to try to run more tests on the coils, etc to see if they can get the vehicle to throw a code. The SA did drive the vehicle and notice the problem, so hopefully they can do something about it.

I will keep you guys updated. The problem started after I had the wastegates replaced and the system flashed to the current software. I feel this was a big mistake and wish they could flash it back to OEM, but that's not happening.

I should have a call back today with an update. My car is also a 6MT

Michael

[joec500]

Originally Posted by rbaldwin28

Yea, he is 2007 MSD80 same as me. You are the first person I have seen with a 6MT though. Are you tuned? Procede or JB?

Yup V4

[ollie]

fuel pressure regulator and fuel pressure sensor.

[rbaldwin28]

Originally Posted by joec500

Yup V4

Me too. You will be glad to know if the HPFP I had installed today does not fix the issue I am going to talk to Shiv about bringing my car to him so he can have first hand experience with the problem. Its 8 hours to the bay but I need this to be resolved. PM me if you want to be in the loop.Badass335 and i have been talking and brainstorming for a week or so but the more heads the better in my opinion.

[badass335]

Originally Posted by rbaldwin28

Me too. You will be glad to know if the HPFP I had installed today does not fix the issue I am going to talk to Shiv about bringing my car to him so he can have first hand experience with the problem. Its 8 hours to the bay but I need this to be resolved. PM me if you want to be in the loop.Badass335 and i have been talking and brainstorming for a week or so but the more heads the better in my opinion.

DAMN DUDE!!!!! i was hoping that was the case as i was just going to look at paying for the upgraded pump myself!!

I was just thinking..... do you guys think its a faulty procede?? Im in the I.T. world and we have defective parts, motherboards etc.... do you guys think its a faulty board on the procede?

[badass335]

Oh and i'm 02/2007 production Auto, MSD80 with latest flash as of 2 months ago. I think its 34 or 35.

[joec500]

Originally Posted by rbaldwin28

Me too. You will be glad to know if the HPFP I had installed today does not fix the issue I am going to talk to Shiv about bringing my car to him so he can have first hand experience with the problem. Its 8 hours to the bay but I need this to be resolved. PM me if you want to be in the loop.Badass335 and i have been talking and brainstorming for a week or so but the more heads the better in my opinion.

Please include me, I live about 45 mins from Shiv's house the problem is my misfires are not easily re-produceable and at times they do not come back for several thousand miles, I also think it could be due to Carbon build up on our valves.

[joec500]

Originally Posted by badass335

DAMN DUDE!!!!! i was hoping that was the case as i was just going to look at paying for the upgraded pump myself!!

I was just thinking..... do you guys think its a faulty procede?? Im in the I.T. world and we have defective parts, motherboards etc.... do you guys think its a faulty board on the procede?

Doubtful as I had the same issue when I had the old V3. Also I have gone through 2 V4's, so I really don't think it's faulty hardware. My guess is it has something to do with our older model N54 setups and possible DME's???? Or as I mentioned in another response, carbon buildup since we do have older cars with more miles than most? I have 49k miles on the clock.

NOTE: also had the same issues with my GIAC tune....but stock I have zero issues....

[rbaldwin28]

Originally Posted by joec500

Doubtful as I had the same issue when I had the old V3. Also I have gone through 2 V4's, so I really don't think it's faulty hardware. My guess is it has something to do with our older model N54 setups and possible DME's???? Or as I mentioned in another response, carbon buildup since we do have older cars with more miles than most? I have 49k miles on the clock.

NOTE: also had the same issues with my GIAC tune....but stock I have zero issues....

I have had this since 35,000 miles on the car and now have 44,000. Every time a new map or upgrade comes out the miss fires go away but quickly return and get progressively worse the longer I go. Its almost like as the DME adapts it gets worse then I load a new map and it runs great for a while. I just got home with my car and a new 933 pump (refurbished). I am going to put the procede back on right now and we will see. Oh and if the problem was carbon build up don't you think it is unlikely we all have miss fires in cylinder 6

[MikeTerp]

I had this problem twice with my 97 E39 (528) and BOTH times it involved a camshaft timing sensor. After they replaced it the second time (with something like 45K on the clock) I drove it for eleven total years and over 166K miles before buying a new BMW. Have no idea if this is your problem, but it will produce symptoms EXACTLY like you describe. Good luck.

[badass335]

Originally Posted by rbaldwin28

I have had this since 35,000 miles on the car and now have 44,000. Every time a new map or upgrade comes out the miss fires go away but quickly return and get progressively worse the longer I go. Its almost like as the DME adapts it gets worse then I load a new map and it runs great for a while. I just got home with my car and a new 933 pump (refurbished). I am going to put the procede back on right now and we will see. Oh and if the problem was carbon build up don't you think it is unlikely we all have miss fires in cylinder 6

+1. Always comes back with a vengence.
I also have meth running so wouldn't meth keep my valves side clean?

[badass335]

Hey Marcel,

Whats the status of your car? Any more progress?

[rbaldwin28]

Originally Posted by badass335

+1. Always comes back with a vengence.
I also have meth running so wouldn't meth keep my valves side clean?

Yea, meth would keep them cleaner than fuel would I think. My fuel pump has fixed mine for now but I think it will return. I still hear and feel this anomaly right at the shift only when running the tune.