Diagnosis: Jerk/Misfire/Hesitiation from engine

[runstile]

I have read a couple threads with people complaining about similar situations.

Background: 2007 335i 6MT, 95k mi, had HPFP replaced (before I owned it), had 3 fuel injectors replaced 2k miles ago

This occurs usually at highway speeds, while in 6th (not downshifting), usually while passing.

Here's the story: As I step on the throttle (50%-WOT) I sometimes get a jerk/misfire in a range of 2000-3500 rpm. Sometimes it even happens while I'm using Active Cruise, so I'm pretty sure the throttle position isn't a problem.

I have wondered if it puts too much stress at lower rpms from not downshifting, but the power is there, so...

I have been to the dealer twice, today being the 3rd. The techs say that since it isn't throwing a fault code they can't say it is the HPFP or other injectors (which I think is the root cause). The tech finally conceded that something was wrong when I recreated the misfire with him in the car, and said he thought it was the driveshaft. This condition was present before and after the 3 injectors were replaced.

Now, I am not disrespecting the technician, god knows he has worked on these cars more than I have. However, I am a mechanical engineer and I'm not a dumbass, and this is most likely not drive shaft issue (it is a constant rotating component, and the frequency and irregularity of this occurrence doesn't mesh). I've driven the car aggressively in other situations and never been able to recreate this instance. There is no problem above or around 4000 rpm.

What should I do? I'm thinking about going to another BMW dealer to see if I can get the other 3 injectors replaced and/or the HPFP done as well. Has anyone experienced the same or similar situation?

[e66man]

When is the last time the spark plugs were replaced?

[runstile]

Good question, I'll check today when I pick it up. I asked them to check the plugs the last time I took it in and they said they were fine...

[White94RX]

You intake ports are carboned up. That's the exact symptoms it causes. Rough/jerky acceleration at about that RPM range with no fault codes stored. It's very common on the N54 engines.

We have a cleaning procedure with a media blaster and crushed walnut shells. It's very effective. Probably costs about 6 hrs labor for a car out of warranty.

[runstile]

You intake ports are carboned up. That's the exact symptoms it causes. Rough/jerky acceleration at about that RPM range with no fault codes stored. It's very common on the N54 engines.

We have a cleaning procedure with a media blaster and crushed walnut shells. It's very effective. Probably costs about 6 hrs labor for a car out of warranty.

I wonder if I can sell my soul for 6 hours of BMW labor... I have heard of this procedure and I'm definitely interested.

On a serious note, the other day after picking up my car with no solution, I tweeted to Rick Hendrick BMW about my dissatisfaction with the service department. Yesterday I got a tweet from them, saying that they were sorry and that the manager would be in contact with me shortly.

Sure enough, he called me up and asked a few questions, agreed that the issue needs to be fixed, and offered to change the spark plugs out of goodwill if I wanted to do that. Not only that, but he also mentioned that because of my service log, if this condition did turn into something serious out of warranty he said all he had to do was call BMW and they would honor the service "as if" under warranty. I know most companies do this if the condition occurs while under warranty, but it was nice to know that he would play ball for me.

Needless to say this was a pleasant surprise and I tweeted a generous thank you after I got off the phone. Maybe they aren't so bad after all. However, I still think that I should have been approached by a manager out of standard practice; I think it shouldn't have had to wait for a negative backlash via social media.

[mryakan]

I wonder if I can sell my soul for 6 hours of BMW labor... I have heard of this procedure and I'm definitely interested.

On a serious note, the other day after picking up my car with no solution, I tweeted to Rick Hendrick BMW about my dissatisfaction with the service department. Yesterday I got a tweet from them, saying that they were sorry and that the manager would be in contact with me shortly.

Sure enough, he called me up and asked a few questions, agreed that the issue needs to be fixed, and offered to change the spark plugs out of goodwill if I wanted to do that. Not only that, but he also mentioned that because of my service log, if this condition did turn into something serious out of warranty he said all he had to do was call BMW and they would honor the service "as if" under warranty. I know most companies do this if the condition occurs while under warranty, but it was nice to know that he would play ball for me.

Needless to say this was a pleasant surprise and I tweeted a generous thank you after I got off the phone. Maybe they aren't so bad after all. However, I still think that I should have been approached by a manager out of standard practice; I think it shouldn't have had to wait for a negative backlash via social media.

Just out of curiosity, did you ask to talk to the manager before going online. I have never had a problem speaking to a manager when I needed to escalate or double check something and rarely of ever hear of someone being brushed off of they ask politely. You'd be surprised how much you can get done when you chat up the service advisor and get friendly with them. Even better when you know the service manager. I have known the service manager at my dealership since I moved to town some 14+ years ago and he is one of the reasons I keep coming back. So much good will over the years, hard not to be loyal when well treated.

[runstile]

Just out of curiosity, did you ask to talk to the manager before going online. I have never had a problem speaking to a manager when I needed to escalate or double check something and rarely of ever hear of someone being brushed off of they ask politely. You'd be surprised how much you can get done when you chat up the service advisor and get friendly with them. Even better when you know the service manager. I have known the service manager at my dealership since I moved to town some 14+ years ago and he is one of the reasons I keep coming back. So much good will over the years, hard not to be loyal when well treated.

I did not, however my regular service advisor had told me that he spoke with the manager and made sure he was aware of my situation. I guess I figured since he was aware that there was nothing to do at that point.

[335moon]

Happened once to me and the cel went on. Tech couldnt find an issue, didnt happen again. The report shows they tested each part and spark plug with no luck. That sucked.

[mryakan]

I did not, however my regular service advisor had told me that he spoke with the manager and made sure he was aware of my situation. I guess I figured since he was aware that there was nothing to do at that point.

Yeah, sometimes you need to be a little bit more politely pushy . I can see how busy these dealerships get, so not surprised some things get "forgotten" . But the squeaky wheel gets the grease, right?
On a serious note though, my best advice for dealing with such issues, is to go at non-rush times when they are not too busy with tons of customers, or stay in for a while at the dealership till the morning rush is over. I sometimes wait for my car if it takes less than 2 hrs to finish (I will be wasting at least 1 hour taking the shuttle anyway or driving back to the dealership), and typically an hour after all the rush is gone, I find I can talk a bit to my SA or the service manager, chat with them, talk about other things, like cars in general or their vacation plans, etc. Goes a long way towards getting good service. At the very least, they will remember you, and as a nice guy, not as that jerk who always complains and is always difficult, not that I am implying anyone here is like that, just saying.

[Sparc_it]

I am having a similar issue with my 2010 335i (25k miles). I took the tech for a 30 minute ride and could not recreate the issue. But if I am cruising on the highway between 2-4k I will get the hesitation on occasion.

Same result when I got the car back, no issues, no fault codes, nothing done.

[Bebik22]

Need help. my 335i 2009 shakes a little on the start. I took engine cover off to replace spark plugs and noticed that that there are many seeds right next to cavity of coil/sparkplugs. What is this small hole next to coil.