[MeanMangoMan]

Originally Posted by chappy

I had the same problem from putting into M1 using paddles then changing into M2 not going fast but around 3000rpm it would double jerk or miss no codes would show and that was on vishnu V4 but since then have updated to V5 old firmware,still did the same, but the latest beta 1-21 firmware has solved that issue completely,no jerking what so ever very smooth like stock.
I thought it was spark plugs,but i was wrong.

I dont have anything besides exhaust right now on the car...

[WhiteonWheat]

Guys,

Sorry to dig up an older thread.

I'm having this "jerking" issue as well. Mentioned on a comment was the HPFP...and since being on here a little while and reading a bunch - it seems that BMW has had it's fair share of issue with the high pressure fuel pump - so I'm wondering if that's my issue. I have a 2011 e90 MT.

Here's my issue.

Sometimes - not all the time I experience this:

When I'm crusing and have the gas pedal still (as in driving on street roads and even highway and I'm not accelerating or de-v...just a constant speed), I feel a "JERK!"....smooth....."JERK!".....smooth....."JERK !"....(repeat). It seems to quit, if I take my foot fully off the gas pedal and then back on, but after a little while, it might start back up.

One thing that seems to help - but is sooo weird. If I ever experience the smooth/jerk/smooth/jerk, and pull into a parking lot - turn off the car, wait 30's or a few mins and re-start...I can make it all the way home without feeling the "jerk" once.

So....an educated guess would be maybe the HPFP...b/c the "jerk" doesn't necessarily feel like a TRANNY issue (not that hard), it's more of a quick and sudden decrease in acceleration and then it's back on and then another decrease in acceleration - which leads me to think it's the fuel, cutting off or flow is decrease and then the pressure goes back up, etc..

I'm going to take it in and specifically ask that the HPFP be checked...

I'll report back with my findings for everyone...

Thanks Guys!
-WoW

[335twins]

crap, i am having similar problem, have another post but found this one and it seems like the same issue. My HPFP was replaced a year ago, but who knows, maybe its dying again, to me it happens when going around 80mph, crusing, adding some throttle i feel jerk, go, jerk go, jerk.. anyone figure out what the problem was? i might call the dealer to have it checked but they usually are useless if there are no codes..

[fastloop]

I used to have this issue mainly in 1st gear where it felt like any throttle application got amplified by a factor 10x. So even if I applied a constant throttle, it felt like I applied 3/4 throttle, then backed off and stabbed it again. This made it really hard to do a quick launch unless you got everything just perfect.

I fixed this by replacing both pressure converters (#4) (~ $91.40 each from Tischer)
http://www.realoem.com/bmw/showparts...75&hg=11&fg=45

I'm not saying this is the issue as there is lot of things that may cause this, but I would check all the vacuum lines across the engine, vacuum canisters etc and make sure you don't have a leak. Odd behaviour with the pressure converters may cause the wastegates to operate badly causing the jerky behaviour.

It's a possibility and fairly easy to swap.

Any codes that may indicate a HPFP issue?

[335twins]

I looked over the charge pipe, diverter valves and it looks ok to me, will look over all the vacum lines to see if there are any cracks. I dont have a code reader so i dont know if there are any shadow codes..this is really frustrating as u said because it could be alot different things doing this.

Originally Posted by 335rocks

I used to have this issue mainly in 1st gear where it felt like any throttle application got amplified by a factor 10x. So even if I applied a constant throttle, it felt like I applied 3/4 throttle, then backed off and stabbed it again. This made it really hard to do a quick launch unless you got everything just perfect.

I fixed this by replacing both pressure converters (#4) (~ $91.40 each from Tischer)
http://www.realoem.com/bmw/showparts...75&hg=11&fg=45

I'm not saying this is the issue as there is lot of things that may cause this, but I would check all the vacuum lines across the engine, vacuum canisters etc and make sure you don't have a leak. Odd behaviour with the pressure converters may cause the wastegates to operate badly causing the jerky behaviour.

It's a possibility and fairly easy to swap.

Any codes that may indicate a HPFP issue?

[335twins]

Please someone help me before I pop a vein in my neck, this jerking is really pissing me off, i feel like my engine is gonna die on me. I would go back to the dealer and maybe that's what I should do but they are useless unless you get a engine light they won't fix anything. If someone in Arizona has a logging tool please pm me.

Thank you

[Nyc_BK_335I]

I have the same type of "jerk" but I have a e90 n55. I brought the car into the dealer and they just said no problems were found and said that's how the turbo in the car is. pretty
Bs is you ask me.

[N54_Fan]

Originally Posted by 335twins

Please someone help me before I pop a vein in my neck, this jerking is really pissing me off, i feel like my engine is gonna die on me. I would go back to the dealer and maybe that's what I should do but they are useless unless you get a engine light they won't fix anything. If someone in Arizona has a logging tool please pm me.

Thank you

What year is your car? I started having the same issue on my 2007 at 55,000 miles. I ended up doing all the maintainance things since I plan to keep the car. Each thing I did improved it some but the biggest improvement was when I got the valve wlanut blasted.

Check or do the following in this order....at least this worked for me.

1) walnut shell blast the valves - ~$400-$600
2) replace vanos solenoids - ~$200-$250. Or trying cleaning them 1st...FREE
3) replace coils - ~$350
4) replace fuel injectors -$more expensive. I dont recall price.

You should be throwing codes for these to figure out what to try first. You may need them all done. I had a half yellow CEL only at the track and not street driving and my tune was set to clear codes so I never knew what ot was. However, I still got the jerky feeling on DD with NO CODES. Since I planned to keep the car forever I started down the list except I did cheapest to most expensive. When I got to blasting valves it was resolved. My FI were replaced 4 of 6 under warranty just before it ran out so I never did the other 2.

Good Luck

N54_Fan

[335twins]

I had the following done already:

1-Chemical treatment by the dealer-not sure how good this is comparing to walnut blasting
2-Spark plugs replaced
3-Fuel injectors replaced
4-HPFP replaced under the recall

I havent replaced the coils or vanos solenoids. I think the first step would be to get cobb to see if there are any codes and then go from there. I still have warranty but the dealer will say that there are no codes and that everything looks good, bla bla bla, so i need to get something before i go in.

Thanks

Originally Posted by N54_Fan

What year is your car? I started having the same issue on my 2007 at 55,000 miles. I ended up doing all the maintainance things since I plan to keep the car. Each thing I did improved it some but the biggest improvement was when I got the valve wlanut blasted.

Check or do the following in this order....at least this worked for me.

1) walnut shell blast the valves - ~$400-$600
2) replace vanos solenoids - ~$200-$250. Or trying cleaning them 1st...FREE
3) replace coils - ~$350
4) replace fuel injectors -$more expensive. I dont recall price.

You should be throwing codes for these to figure out what to try first. You may need them all done. I had a half yellow CEL only at the track and not street driving and my tune was set to clear codes so I never knew what ot was. However, I still got the jerky feeling on DD with NO CODES. Since I planned to keep the car forever I started down the list except I did cheapest to most expensive. When I got to blasting valves it was resolved. My FI were replaced 4 of 6 under warranty just before it ran out so I never did the other 2.

Good Luck

N54_Fan

[335twins]

when does the jerk feeling happens? is it at any speed/rpm? WOT/partial throttle?

Originally Posted by thestevenli

I have the same type of "jerk" but I have a e90 n55. I brought the car into the dealer and they just said no problems were found and said that's how the turbo in the car is. pretty
Bs is you ask me.

[Apollyon]

My wife's AT 535xi had this jerky feeling for the 1-2 gear. I went to the dealer and they change the transmission. They gave my car back and the problem still there, so brought it back and they change the transmission again. Problem fixed. Took 1 and a half month to do this.

[nailer335]

335twins,

I have this symptom too. I get code 29F3, which indicates that I need to replace my LPF sensor. Theres some talk about this currently in a few other threads I think. Im in AZ and have a BT cable. PM me

[335twins]

PM sent, sorry my mailbox was full.

Originally Posted by nailer335

335twins,

I have this symptom too. I get code 29F3, which indicates that I need to replace my LPF sensor. Theres some talk about this currently in a few other threads I think. Im in AZ and have a BT cable. PM me