[vishaltb]

Car:
N54 E90 2008 with GIAC and a few light mods...

Symptom:
Misfiring/Slipping while accelerating in gears 3-6 between RPMs 2500 - 5500.

Hypothesis Diagnosis:
Not the clutch. (could've been the clutch slipping)
Changed spark plugs even though i didn't have a CEL.
It's very random. happens hot/cold engine. happens some days/some not.
Cleaned the air filter thoroughly.

I've gotten the new HPFPs in my car now after the recall. I'm not sure if the injectors were replaced (have to call the dealer and ask).

I've been through the bad HPFP symptoms with the old (stock) HPFP:

Long crank starts

Once started, car struggles to stay on. RPMs drop.

Reduced Engine Power...

Now I just have the misfiring symptom along with the RPM's dropping at idle sometimes (again, random). The idle's dropping during idle is new and getting more noticeable.

I went to a friend of mine who was a master tech for BMW, he ran diagnostics for the ignition parts with a computer and ruled out the spark plugs and also didn't see any voltage spikes either at different RPMs.

I just wanted to know if anyone else has had these symptoms or if anyone has ideas whether its the new HPFP or an injector? Hopefully its not the turbos. It could also be a bad fuel tank. I've always put 93 in my car, but seldom with random gas stations, mostly with popular ones (shell, exxon, sunoco, valero).

My problem is that I'm not under warranty anymore with 52K miles on the car. The HPFPs are covered till 100K now but I'm not sure if thats the issue. I'd rather know its for that so I'm covered. If not then I'll have to spend the money for the injectors anyways but I'd like to know that I'm getting myself into that.

Any help is much appreciated!

[LJS330i]

I had the exact same issue happen on my 2010 E90 335i. After the HPFP replacement it stuttered like that randomly. I took it back in, they replaced 3 injectors and coils. Did not resolve completely. Then they replaced something with the valves. Did not resolve and actually got worse. Then had another HPFP replaced. Same issue. Then they replaced the remaining injectors. Did not resolve. I took the issue up with BMW NA. They offered me Trade Assist. I ended up getting a 2011 335i with an N55. I've had the car for over a year and I love it. It's never seen the dealer service center. I had my N54 powered E90 in about 10 times.

LJS330i

[vishaltb]

Originally Posted by LJS330i

I had the exact same issue happen on my 2010 E90 335i. After the HPFP replacement it stuttered like that randomly. I took it back in, they replaced 3 injectors and coils. Did not resolve completely. Then they replaced something with the valves. Did not resolve and actually got worse. Then had another HPFP replaced. Same issue. Then they replaced the remaining injectors. Did not resolve. I took the issue up with BMW NA. They offered me Trade Assist. I ended up getting a 2011 335i with an N55. I've had the car for over a year and I love it. It's never seen the dealer service center. I had my N54 powered E90 in about 10 times.

LJS330i

i hope that doesn't happen to me. I made an appointment tomorrow to bring it in... hopefully it gets resolved with something that is covered under warranty. I also hope that this problem gets FIXED permanently.

I'd hate to throw away all the hours of labor I put in to install the bulbs for my halo and fogs which I did this past weekend...

[vishaltb]

Originally Posted by TrackRat

It could be many things causing a misfire. Not sure what you mean regarding "slipping" however. If the clutch is slipping the RPM increases but the car doesn't accelerate properly. You can usually smell the clutch burning if it is slipping that much. More than likely you will need the dealer to run a diagnostics to find if it's the injectors, ignition coils, fuel pressure sensor, HPFP or something else.

I take back the "slipping" symptom. Wrong word choice.

As a layman, I can't think of the proper word for describing the symptom. So heres more than one word for describing it.

While accelerating per gear, it'll go... vrrrmmmmmmSKIPmmSKIPSKIPSKIPmmmmmmmSKIPSKIPmmmmmmm mm....

its almost as if the acceleration sound of the engine goes away and you feel a jerk because it stops accelerating for like .2seconds for every 'SKIP'

hope thats better...

[vishaltb]

So I called the dealer to find out this info:

Injectors 1, 2, 3 replaced in November 2009 @ 27.5K miles.
Injectores 4, 5, 6 replaced in December 2009 @ 29K miles.

There was a recall for the old injectors after that when I had 47K miles but the NEW injectors I had in my car were not under recall...

I also found out that the injectors are covered for up to 2 years after install, unlimited miles. So now that both my HPFP and Injectors are covered, hopefully the problem is because of one or both of those parts, and I wont have to pay anything.

I will update you guys on the situation as I get some news after tomorrow. So keep a lookout!

What will suck is that if it is the Injectors, I will have to go get a re-flash for my GIAC tune.

[vishaltb]

3 of my wheels are bent. the back right one is severely bent apparently. the tech thinks that the issue is because of the wheels.

need to get new wheels.
http://www.e90post.com/forums/showthread.php?t=544265

will repost after wheel/tire exchange is done and new road test is completed.

[m1bjr]

So what happened?

[AWD Addict]

Based on the way the OP describes it, its not a bent wheel. Lots of people are experiencing this. I don't know much about the tune, but people are experiencing this on stock cars as well.

OP, for the record, all fuel system components are under extended warranty to 100k, not just the pump.