[Spoolin Montego]

Very informative thread. I'm trying to fix a misfire issue I have on cold starts where the car will not idle and will eventually go into limp mode, after a minute or so however the car will run fine unless I am driving it hard in which It will misfire when I go WOT. So far i've replaced the plugs, coils, injectors, HPFP sensor and walnut blasted. What should I look into next? Possible to clean this vanos thing I've heard about.

[gray335coupe]

love this

Originally Posted by Jeff@TopGearSolutions

All First Time Tuners to this platform should read this sticky. This car has a history of misfires and they are all well documented and typically easy to fix. If you are new to tuning your vehicle and you have over 25,000 miles on your vehicle spark plugs the first thing you should do before installing your tune is get fresh spark plugs. This problem is so common for newly tuned vehicles that even Cobb has made a video.

Cobb's Video on Misfires
http://www.youtube.com/watch?feature...&v=FsNK1ySAlSo


Here is a list of things you can try in no particular order and there may be more. I would suggest starting with the least expensive ideas first.

-Spark Plug Gap
- New Spark plugs
- Swapping Coilpacks
-New Coilpacks
-Injectors
-High Pressure/Low Pressure Fuel Pump
-Carbon Build up in intake valves
-Vanos Solenoid

Troubleshooting Misfires

Multiple cylinders:

Check Your Spark Plug Gap:
The cheapest quick fix is to ensure your spark plug gap is within spec. BMW 135i and BMW 335i Stock Spark Plug gap for 2007-2010 is .028".

Replace Spark Plugs:
If this fix does work then you still may want to consider changing your spark plugs to new, especially if they have over 25,000 miles on them.

If the misfire is on one or two cylinders:
Try swapping coil packs to see if the problem moves to another cylinder: i.e. if cylinder 1 is misfiring, swap coil 1 to 3 and see if the misfire now happens on cylinder 3. If it moves the coil pack needs replacement.

If the misfires does not move then you need to check your spark plug gap and or replace them before moving on to the next steps.


If changing spark plugs and moving/replacing coil packs does not work it could be the following:


Leaky Injector: Your spark plug(s) would show an indication of fouling and smell of fuel. This would be an indication your injectors may be leaking at the seals. A leaky injector in most cases also causes a rough start and or idle.

Weak/ Failing Low Pressure Fuel Pump: Not as common but a weak LPFP can cause misfires. You can measure this by trying to get logs from your tune of the LPFP voltage/pressure. You can also check your fuel trims to see if they are exceeding 31-34%. (However, your tune may just need adjustment). We advise to contact your tuner of choice in regads to fuel trims and if your low pressure pump may be on the fritz.

Weak/Failing High Pressure Fuel Pump: Not as common but a weak HPFP can also cause misfires.

Excessive Carbon on Intake Valves: This will happen to all N54 Engines. It is a result of not having fuel sprayed over the intake valves like traditional Port Fuel Injection. Since the N54 is direct injection over time the intake valves gunk up with carbon deposits. We've seen historically that after 35,000 miles all N54 vehicles could use a Intake Valve Cleaning. The benefits for most are smoother power delivery, increased power, smooth idle and in some cases a fix for misfires.

Vanos Solenoids: Usually attributed with Vanos codes, the Vanos Solenoids can cause misfires. A quick fix is to clean them. See DIY.

[Greatdane84]

Originally Posted by Spoolin Montego

Very informative thread. I'm trying to fix a misfire issue I have on cold starts where the car will not idle and will eventually go into limp mode, after a minute or so however the car will run fine unless I am driving it hard in which It will misfire when I go WOT. So far i've replaced the plugs, coils, injectors, HPFP sensor and walnut blasted. What should I look into next? Possible to clean this vanos thing I've heard about.

Possible to clean but usually only a temporary fix. You start by swapping the 2 solenoids around and blowing compressed air on them to clean. I'd recommend just buying but vanos throw a specific code. Quite a few posts on it

[awawd335]

I've been having cylinder 2 misfires only with WOT. It happens pretty much every time I do a prolonged pull. It is also associated with a 2AAF code (not sure the significance of this one). I have about 83000 miles (mostly highway) and have been tuned for most of it. Went FBO recently. Had intake valve cleaning a couple weeks ago (just before I had this problem start).

I tried swapping coil packs but the code stayed with cylinder 2. I next pulled the spark plug, but it seemed to be in good shape (only about 10,000 miles on the plug) so I swapped it with a different plug. The misfire code stayed with cylinder 2.

Any thoughts on where I should go next? Thanks.

[Andrew5]

Cars in the shop getting new spark plugs put in as we speak

[Welterweight]

just had this happen last night

Cylinder 1 misfire

Car is new to me with 65k miles.

I plan to replace plugs first and see if it helps.

Car is mostly stock with Cobb AP, K&N Drop in, 7" FMIC

[andyho123]

Hey guys this problem is giving me the biggest headache and frustrations.


I'm running jb4 g5 FBO. I run either map 2 or map 5 if I run e85. I keep having misfire on cylinder 1.
I have:

-changed bank 1 injectors
-new coils and plugs
-carbon clean up (100 miles)

The misfire only happen in cylinder 1. Not all the time, but it will trigger whenever I thought I fixed the problem, so annoying!!!

Once it popped up 29dc - "cylinder shut off" code. This code has not come back since the last time. But I would get misfire on cylinder 1. I would say 1 out of 5 run the misfire will trigger.

Please help me guys I'm so clueless at this point.

[andyho123]

Originally Posted by awawd335

I've been having cylinder 2 misfires only with WOT. It happens pretty much every time I do a prolonged pull. It is also associated with a 2AAF code (not sure the significance of this one). I have about 83000 miles (mostly highway) and have been tuned for most of it. Went FBO recently. Had intake valve cleaning a couple weeks ago (just before I had this problem start).

I tried swapping coil packs but the code stayed with cylinder 2. I next pulled the spark plug, but it seemed to be in good shape (only about 10,000 miles on the plug) so I swapped it with a different plug. The misfire code stayed with cylinder 2.

Any thoughts on where I should go next? Thanks.

I would go for injector next. That seems to be the problem. That's the last step check. Hope this helps

[flako05z]

[boostedbmr]

This past week I started having misfires on cold startups from what this thread is telling me is that it's a leaky injector, but the thing is I'm getting missfires in multiple cylinders mainly cyl 1 & 4 sometimes cyl 5. Is it likely that multiple injectors are leaking at the same time?? Or maybe these missfire are related to something else like the hpfp?

[Jeff@TopGearSolutions]

Originally Posted by chrstphr335

This past week I started having misfires on cold startups from what this thread is telling me is that it's a leaky injector, but the thing is I'm getting missfires in multiple cylinders mainly cyl 1 & 4 sometimes cyl 5. Is it likely that multiple injectors are leaking at the same time?? Or maybe these missfire are related to something else like the hpfp?

It's likely your spark plugs.

[boostedbmr]

Originally Posted by Jeff@TopGearSolutions

It's likely your spark plugs.

I change them about 2k miles ago, this has been going on over a month only happens at idle occasionally and I as well get jitter from time to time.

I have not gotten a misfire on WOT yet and I have been pushing the car frequently

[Welterweight]

I recently got a Vanos Solenoid code thrown and plan to install two new ones as they are most likely original and I am at 67k. My question relates to the Cobb and the ability to view the required and actual values for both intake and exhaust on the Vanos. Should the values or actual match the required? My Exhaust is almost dead on. The intake is however quite far off. Thank you!

[Jeff@TopGearSolutions]

Originally Posted by chrstphr335

I change them about 2k miles ago, this has been going on over a month only happens at idle occasionally and I as well get jitter from time to time.

I have not gotten a misfire on WOT yet and I have been pushing the car frequently

Pull the spark plugs then and see if it's a leaky injector, the plug would be fouled with fuel. It could also be a leaking valve cover gasket. I know you said multiple misfires but it's worth the 20 minutes to pull the plugs and take a look and you may get lucky and find a quick answer.

[carl425]

Hi, first post here on this awesome resource and I'm looking for some help...

So, I suffered the failed MOSFET syndrome that it seems is quite common to E90/92/93 with a MSD80, so I ordered 6 of them and replaced them all--well actually a local TV repair place did it for $50 (winning!).

Brought the boards home, reinstalled in the DME case and put everything back together. Tried to start it and though it cranks, it doesn't fire at all. I've checked EVERY connection (there aren't that many) and every logical fuse.

The P30BA that started it all is gone but now I get the following:
ECU
P2ACC, DME main relay, switch delay
P29F3
P29DB

I've checked the DME relay, if it's the one in the DME tray/compartment and the fuel pump fuse, and both are good. What else could be causing it to not get fuel (my assumed problem at this time)?

Any help with this is greatly appreciated!

[Eurocraze]

ill tell you that a bad or dirty vanos solenoid will not throw a specific code all the time...

however, if the intake side one is way off, you will have misfires and shitty idle/gas mileage/power. i changed mine at 62k, seems to be the time these things start to go...

[MM Performance]

I had misfire issues and throwing all kinds of codes, would only happen consistently when operating higher boost on tunes and rarely on stock tune and also would only happen when going WOT and usually on a pull from lower rpm. My issues were a bad coil pack on cylinder I found by swapping them and also I needed to clean my vanos solenoids. After 0 issues and running 20psi without a hiccup.

[Esveesh]

What exactly is a misfire anyways?

[brosidelong]

Just had a misfire pop up in Cyl 1 last week. Car has been telling me to change the plugs for a while, but never got around to it with 60 hour work weeks. Bought new OEM Bosch plugs, not the BMW branded ones *before reading about the differences in insulator design*. Replaced all 6 today, and still getting misfires. Swapped the coils between #1 and #2, still no changes. Total drive after replacing the plugs is about a mile. Do I need to put some more drive time on the car for the ECU to adapt to the new plugs?

[beetle6986]

Originally Posted by brosidelong

Just had a misfire pop up in Cyl 1 last week. Car has been telling me to change the plugs for a while, but never got around to it with 60 hour work weeks. Bought new OEM Bosch plugs, not the BMW branded ones *before reading about the differences in insulator design*. Replaced all 6 today, and still getting misfires. Swapped the coils between #1 and #2, still no changes. Total drive after replacing the plugs is about a mile. Do I need to put some more drive time on the car for the ECU to adapt to the new plugs?

Did you get a new misfire code after swapping the coils? You might have a bad injector.

[udderfailure]

I've been hitting my head against the wall for about 3 months now trying to figure out this misfire. Here's the short story

Started misfiring about 6k miles ago on Cyl 1. Put in new spark plugs - no impact.
Took it to a shop and they suggested walnut blast so we did that - no impact.
Took it back and they replaced fuel injector on cylinder 1.

That seemed to fix it for about 5 months. Then it started misfiring above about 3k rpm.

Took it to the dealer and they pulled the codes and said it was the Low pressure fuel sensor (I knew that wasn't it since my other 335xi has had that code for a year or more) but I was willing to give it a try, so I switched it myself. Still misfired

Ran the codes again and it said both pre-cat O2's were bad... so i swapped those - still misfired.

At this point there are no codes and it still misfires under any real load (above 2.5k).

All I can figure it would be now is: The Fuel Injector (though the one in the affected cylinder was replaced 6k again), the ignition coil (i've swapped the coils and the misfire didn't more), or the low pressure fuel pump.

The one of those that makes the most sense is the fuel pump (unless i'm missing something - gasket issues, etc...) but I don't have a way to know for sure.

Any insight would be hugely appreciated! It's been a great learning experience to work on the car, but i'm ready to get it fixed (more to say my wife is, she's got the need for speed... or reasonable acceleration).

Edit* It is also getting about 8 mpg right now and it only misfires when it's in gear - it free revs just fine. The bad MPG makes me feel like it could some how be the injector. Is it common for injectors to get stuck open when they're new?

[phv628]

Post the codes that come up on your JB4 first!