[SOLVED??] Recurring limp mode 5-8 misfires, replaced TA, still getting limp mode..??

UPDATE 7/8/2016: A few weeks ago I decided to rule out my spark plugs, injectors and camshaft position sensors, so I swapped all three from one bank to the other. I drove the car 211km (a little over 130mi) and didn't have one misfire. Decided to go ahead with my supercharger install, and I've put another 140km on the car since (over 350km total) and haven't had one issue. I suspect that my issue was the injectors leaking (or clogged) and my switching them around either reseated them causing the leak to go away, or my cleaning efforts unclogged them just enough to no longer cause issues. Either way, the car has upgraded injectors due to the supercharger, so I am hoping I have no more issues and this is solved. Until it happens again, I will go ahead and call this one fixed, but if I have anymore issues I will be sure and update this thread.

Thanks everyone for their input. Now i'm on to fix my DCT leak and wait for the next problem to arise *knock on wood*


UPDATE 5/20/2016: So last night I decided to take the car out for a washer. When I started it up, I noticed it sounded quite terrible. It was popping and backfiring for the first 10-15 seconds. Everything else went okay until I had my misfire again 20 or so km later. Stopped, restarted the car and was on my way. Happened again 10 km later. This time when I restarted, my increased emissions warning and CEL remained and would not go away. 3km later it misfired again. At this point I was at my house, so I pulled it into the garage while it was misfiring, immediately hooked up my laptop and scanned my codes. Aside from the usual 5-8 misfires and emergency program activated codes, this is what I got that I hadn't seen before:

27B1 - Secondary Air System Throughput Bank 2

I've been told that my car sounds like it has an exhaust leak when I first start it up, so I am really leaning toward a fault with the SAI system, whether it be a faulty valve, torn or worn pressure hose, or a bad pump itself (the former two being most likely).

I ordered a used set of valves and pressure hose (from the pump to the valves) from a low mileage M3 off of Ebay for cheap, so I will soon start tearing the car apart (again) and inspecting the pressure hoses and valves. I've read this is a pretty horrible job (some have stated that you need to drop the transmission) but we will see how it goes.

Original Post:

Ill try to keep this to a short and to the point version.

Last Nov/Dec a week or so before putting it into winter storage, driving real slow (maybe 5-10mph, almost idling, as I was coming up to a light) my car began to idle rough, got an increased emissions warning on my iDrive, CEL, limp mode, the whole nine yards. Drove the car a mile or so, turned it off, started it again, and it was gone, but the CEL was still on. So, on my way home I got the same warning again with increased emissions and limp mode. Parked the car, had my codes scanned, and this is what I got (I know some of them likely aren't related to this issue, but I included everything, just in case it helps diagnose the problem):





http://s32.photobucket.com/user/GLPstandard/media/received_10206932218568872.jpeg.html?filters[user]=9534163&filters[recent]=1&sort=1&o=6

Given the symptoms and codes, all my research lead me to think it was my bank 2 throttle actuator. Cool, no big deal. I drove the car one more time, and got the same symptoms (CEL light, limp mode, etc). I put the car away for the winter, and decided I would do the TA as a winter project.

Fast forward a few months, I had my codes scanned again since I hadn't had them scanned since they came back the second time just before putting the car away, and I wanted to verify they were the same codes and the TA was actually the issue before I did the repair. This is what I got:



Relatively similar codes (5-8 cyl misfires and increased emissions). So I had the codes cleared, replaced the driver side (bank 2) TA and called it a day. I was 95% sure my issue was fixed, until today when I took the car out for the first time in 4 months. Drove the car for 30 or so miles, and was driving in slow moving traffic (10 or so mph) and the same symptoms came back (limp mode, CEL, etc.). I turned the car off and turned it back on again, and all was fine. Drove another 15 or so miles, and the same thing came back (again, driving slowly). This is what pops up on the iDrive and dash:





(don't mind the engine oil warning, not related).

So whats the deal? What else, besides TA could it be? I am going to have my codes scanned a third time, but I was honestly sure after EVERYTHING that I read that it was the TA and it would fix my problem. Now I guess I am going to pull the new TA off and put the old back in and someone is going to get a good deal on a brand new TA with less than 100 miles. I honestly am at a loss and have NO CLUE what it could be if it's not the TA, which it apparently isnt.

Specifics of the issue:

-Only affects cyl 5-8
-Only seems to go into limp mode when at low rpms and low speeds
-Turning the car off clears everything until it happens again
-Seems to be a recurring issue every 30 miles or so
-Limp mode is always accompanied by a very light, yet noticeably rough idle

Thought I should also mention, spark plugs have around 7000 miles or less on them, and the car is on a CTEK tender (since around last October when I bought the tender, before that I didn't use a battery tender at all) at all times when not in use, though I am not ruling out a bad battery

Not sure what that could be but I didn't get any misfire codes when my TA went. Rough idle seems to usually be tied to ICV maybe look into that and try eliminating that as a possibility

Have you checked this out yet
http://www.m3post.com/forums/showthread.php?t=928325

I haven't seen that until now, but it had good information. Some of my codes aren't even listed on there, but some were. At this point I am leaning toward ICV, but wouldn't the issue be on all cyls if that was it? I find it weird that only one bank is misfiring.

Don't want to jinx you but could possibly be two issues coming together for a "perfect storm" when my secondary air pump hose went my code wasn't an exact match to ones on the link I gave you but there were "less specific" codes listed. Think of it as your whole VIN being your specific vehicle but the first part of your VIN narrowing a type of vehicle down greatly

PS: my initial thought without any experience or first hand knowledge on the misfire problem. But I'm thinking if there's a problem with the combustion it must be something related to the spark, air or fuel seperately or air/fuel together. You said your spark plugs were done recent enough to rule those out

Did you see this? I know it's hard to see your code with the tons of number posted

http://www.m3post.com/forums/showpost.php?p=15283486&postcount=32

I did see that, which helped a little. The thing is, I suspect the issue is related to a sensor or valve or actuator of some sort that controls just one bank rather than an engine issue or spark plug/coil issue. Reason being, is that the issue is cleared by restarting the car, until it returns, and it always affects the entire 2nd bank. I am going to scan my codes today and see if they are the same, or something different came up. If the same, the TA I bought is coming out and going up for sale. I am leaning toward either a bad o2 sensor or an ICV issue but I am not getting any ICV or o2 specific codes which is what is throwing me off. All of the cases I read about where the o2 sensor or ICV valve (or TA for that matter) was faulty showed codes specific to those parts.

If anyone has had these same symptoms and has any input, please let me know. I am a little aggravated that this is going on after buying a new TA and spending 3 hours putting the bastard in.

Many of the Carly code descriptors are wrong. Failed O2 sensor and as someone mentioned, the secondary air pump hose are two common things that go (especially the bad O2 sensor, had 3 replaced under warranty).

May not be related but just got car back from the shop. TA was the initial diagnosis and both were replaced under my extended warranty. Drove it for a week and got the same messages on iDrive. Shop pulled the codes again and this time it was "governing mechanism" which apparently is also TA related. Apparently one of the new TA's was faulty so had bank two replaced again. Got the car back today and I'll let you know how it goes but bottom appears to be that the replacement TA was bad as well...

This is definetely your O2 sensor

8600RPM wrote

This is definetely your O2 sensor

That was my next place to start. What makes you so sure? (not that I don't believe you, but Im just wondering how you know?) Can I rule out the ICV given that the issue is just on one side, and not on 1-4 as well? I honestly don't know, but I would assume with the ICV the issue should be on both sides?

I got my codes scanned again today, and BMWhat App didn't pull anything up? Guy that was scanning my car said he thinks it might be because the error has to be present for BMWhat App to pick it up (it can't read stored codes). I don't know, because I've never used it

Either way, I drove the car for about 40 miles, and it ran like a champ. No CEL, no limp mode, nothing. I've read somewhere from someone that replaced his TA because it was faulty, and even after replacing it, he got a limp mode once, but cleared the codes and it never came back again. I've also read that sometimes the TA has to adapt to the car? Is it possible this limp mode yesterday was just the car relearning the TA? I am hoping I have no more issues, but I am going monitor it, and if it comes back again, I will probably switch my two pre-cat o2 sensors and wait to see if the issue switches sides.

I am not an expert but it was explained to me that the adaptation process was done by the shop while connected to the computer, not by simply driving around. But others will have to confirm or deny this!

kscarrol wrote

I am not an expert but it was explained to me that the adaptation process was done by the shop while connected to the computer, not by simply driving around. But others will have to confirm or deny this!

I'm guessing not because many people do TA swaps themselves. I've swapped my TA too but I swapped it with a working used one so probably different

Had my codes scanned again, and got some new stuff..CTS and Bank 1 TPS and IAT sensors now, plus the usual 5-8 cyl misfires. Good stuff. Cleared the codes and less than 20 miles later the car went into limp mode again at the BK drive thru. Getting a little annoyed and the three new codes are leaving me

I have these exact same codes. No resolution yet.

|||||||||| wrote

Had my codes scanned again, and got some new stuff..CTS and Bank 1 TPS and IAT sensors now, plus the usual 5-8 cyl misfires. Good stuff. Cleared the codes and less than 20 miles later the car went into limp mode again at the BK drive thru. Getting a little annoyed and the three new codes are leaving me

ICV maybe? seems like it's on one side only

Cbozz wrote

ICV maybe? seems like it's on one side only

Does the ICV control each side independently? The IAT and TPS faults are on bank 1 though (1-4) not on bank 2 which is where my misfires are. Go figure

I was really hoping someone could just tell me "based on your codes and your symptoms, it's 90% likely the issue is _______" (of course, thats what happened with my TA, and we know what happened there). I'm far too frugal to throw money at this car and just start replacing things hoping it fixes the issue, but I may not have a choice it appears.

Right now my possible issues are:

1. o2 sensor
2. Secondary Air Pump
3. Idle Control Valve
4. Intake Air Temperature Sensor
5. Coolant Temperature Sensor
6. Throttle Position Sensor
7. Bad battery

Did I leave anything out, or could I rule any of those out? I feel like the only ones of those that could cause a misfire on one bank and increased emissions is my o2 sensor, but I am not getting any codes for that. Whats a good place to start? o2 sensor me thinks.. So I am going to start by swapping my o2 sensors next weekend to see if the issue switches sides. If that doesn't change anything, Im going to start replacing shit, beginning with the ICV and SAP. Then battery. Then the other three fun little sensors that popped up today. Probably taking that TA off and selling it too. No sense in keeping it if it wasn't even the issue. Oh this is going to be an expensive little project.

I had some engine misfired, so I replace engine thermostat, spark plugs, and O2 sensors, and so far, no misfired.

Bad Battery!
Get that sucker replaced ASAP!
Even you replaced it, hook it over night to an batt. charger.
-Register your battery with your carly OBD2 adapter
-clear the codes
Keep us posted!

Oh I guess I should mention, today when I had my codes scanned, I asked him to check out my battery. He wasn't too sure how to send me the results of the battery log test, but we were seeing that at idle, the battery was around 12.2 volts (IIRC) and giving it gas it went up to around 13.7. Not sure what is normal, or if this even means anything, but I will likely look into replacing the battery regardless if it's causing my misfire issue, as I suspect the three new codes I got today are a result of it and are not really an issue. After 6 years you would think the battery is on it's way out

|||||||||| wrote

Oh I guess I should mention, today when I had my codes scanned, I asked him to check out my battery. He wasn't too sure how to send me the results of the battery log test, but we were seeing that at idle, the battery was around 12.2 volts (IIRC) and giving it gas it went up to around 13.7. Not sure what is normal, or if this even means anything, but I will likely look into replacing the battery regardless if it's causing my misfire issue, as I suspect the three new codes I got today are a result of it and are not really an issue. After 6 years you would think the battery is on it's way out

My nad battery caused my idle to jump on cold starts, little did I know if carly wasnt there to tell me, this could've been an issue.
Yes 6 yrs. , could be enough for a battery to go down south.
Do the battery mirracle as mentioned.
Register your new battery and clear the codes and let us know if you're still running into problems.

I've never heard of a battery causing limp modes, but if it's six years old at least replacing it won't be potentially wasted time and money. Maybe you will get lucky and it will fix the issue.