missing at idle? rough idle?

[mbraun]

Well, I've searched lots and only found idle "missing" or "stumbling" when the hpfp problem (like long starts) is an issue. I find that I get a good shake through the gear shifter (manual shift) and through the seat of my pants, a few times each morning, at various stop lights as I'm waiting for a green.

Yesterday, I noted that if the stumble is bad enough, the engine idle bumps up 200 rpm or so. I hadn't seen that before.

Had BMW do a computer check for codes and nothing showed up. I thought these straight 6's were super smooth, no balance shafts required like a v6 etc. How is every one else's idle? It certainly feels like its 'missing" and recovering.

Let me know! thanks.

[Irishace]

It sounds like the HPFP is on the way out. It just has not thrown any codes yet.

[mshahidz]

Originally Posted by mbraun

Well, I've searched lots and only found idle "missing" or "stumbling" when the hpfp problem (like long starts) is an issue. I find that I get a good shake through the gear shifter (manual shift) and through the seat of my pants, a few times each morning, at various stop lights as I'm waiting for a green.

Yesterday, I noted that if the stumble is bad enough, the engine idle bumps up 200 rpm or so. I hadn't seen that before.

Had BMW do a computer check for codes and nothing showed up. I thought these straight 6's were super smooth, no balance shafts required like a v6 etc. How is every one else's idle? It certainly feels like its 'missing" and recovering.

Let me know! thanks.

I have the same problem! had it since 3 months after purchase (almost 1 year now)...dealer has done nothing!

[mbraun]

I've had the rough idle for probably 5 months already. I have had no problem with long starts though. I'm assuming that the lack of response here is meaning that most people have completely smooth idles, or it doesn't bother them?

As to the comment that the "dealer hasn't done anything". What have they said to you about this? Are they claiming its "normal"?

[dread1]

Originally Posted by mbraun

Well, I've searched lots and only found idle "missing" or "stumbling" when the hpfp problem (like long starts) is an issue. I find that I get a good shake through the gear shifter (manual shift) and through the seat of my pants, a few times each morning, at various stop lights as I'm waiting for a green.

Yesterday, I noted that if the stumble is bad enough, the engine idle bumps up 200 rpm or so. I hadn't seen that before.

Had BMW do a computer check for codes and nothing showed up. I thought these straight 6's were super smooth, no balance shafts required like a v6 etc. How is every one else's idle? It certainly feels like its 'missing" and recovering.

Let me know! thanks.

side note: v6 do not require balance shafts. Inline engines usualy do

[mbraun]

HI. Old v6's did not, but the 90 degree ones often do. From wikipedia: Another balance shaft design is found in many V6 engines. While an inherently balanced V6 engine would have either 60 or 120 degrees angle between the two banks of cylinders, many current V6 engines are derived from older V8 engines, which have a 90 degree angle between the two banks of cylinders. While this provides for an evenly spaced firing order in an 8 cylinder engine, in a six cylinder engine this results in a loping rhythm, where during each rotation of the crankshaft three cylinders fire at 90 degree intervals, followed by a gap of 90 degrees with no power pulse. This can be eliminated by using a more complex, and expensive, crankshaft which alters the relationship between the cylinders in the two banks to give an effective 60 degree difference, but recently many manufacturers have found it more economical to adapt the balance shaft concept, using a single shaft with counterweights spaced so as to provide a vibration which cancels out the shake inherent in the 90 degree V6.

[mshahidz]

Originally Posted by mbraun

I've had the rough idle for probably 5 months already. I have had no problem with long starts though. I'm assuming that the lack of response here is meaning that most people have completely smooth idles, or it doesn't bother them?

As to the comment that the "dealer hasn't done anything". What have they said to you about this? Are they claiming its "normal"?

I thought my car had a problem since previously mentioned. Then, about 3 months ago my car took a crap on me and went into limp mode; had to get it towed. Apparently my cam-shafts failed (NO idea how). I thought that would have solved the problem but it didnt. When i went in to complain, they guy said
" theres no way I can address this issue until something actually HAPPENS, becuase there are too many variables that can cause this, such as bad gas."

I said okay, and am waiting for a failure. I mean, its my third time complaining about it, and they frankly dont care to even check it out. Now i am just hoping for my HPFP to fail, and hopefully thats what it is.

[ronster]

I have similar symptoms (not sure if it's a problem). I sometimes feel something like a kick when waiting @ light. My symptoms probably are not as severe as yours... It didn't feel like shaking just like a little kick... I started noticing it after the HPFP replaced 3000km ago maybe it has been there since day 1 but then I didn't pay attention to it... I feel the same thing on my friend's 335i coupe (his @ 35k) and he said he has had it since new but he never had pump failure. I talked to my SA about it and he basically said the same thing.. can't do anything without throwing a code... which I agree since it doesn't do it all the time... anyway... let us know if you hear anything new from dealer

[dread1]

Originally Posted by mbraun

HI. Old v6's did not, but the 90 degree ones often do. From wikipedia: Another balance shaft design is found in many V6 engines. While an inherently balanced V6 engine would have either 60 or 120 degrees angle between the two banks of cylinders, many current V6 engines are derived from older V8 engines, which have a 90 degree angle between the two banks of cylinders. While this provides for an evenly spaced firing order in an 8 cylinder engine, in a six cylinder engine this results in a loping rhythm, where during each rotation of the crankshaft three cylinders fire at 90 degree intervals, followed by a gap of 90 degrees with no power pulse. This can be eliminated by using a more complex, and expensive, crankshaft which alters the relationship between the cylinders in the two banks to give an effective 60 degree difference, but recently many manufacturers have found it more economical to adapt the balance shaft concept, using a single shaft with counterweights spaced so as to provide a vibration which cancels out the shake inherent in the 90 degree V6.

well thank you for that bit of info. I truly do appreciate it. I was going form experience my vq doens't have balance shafts but my old qr had balance shafts(which I removed). completely forgot to consider the angle of the cylinders and how they have an effect on eachother.

[lavmugen]

i was in the process of searching for this particular topic to see if anyone else had the same thing, guess im definitely not alone.

i have a 2011 model and i've had my car for less than 1 month and for around 2300km. i am starting to get rough idles/vibrations coming from the engine.

it felt like the engine mounts were too stiff and thus transferring the vibrations into the cabin. only happens at idle/very low speed.

GAHHHHHHHHHHHHHH i purposely waited for the 2011 model just so that i dont have to deal with potential hpfp problems down the road

[Simsims]

Originally Posted by dread1

side note: v6 do not require balance shafts. Inline engines usualy do

only Inline 4s do...

Inline 6es are perfectly balanced