[TiAg335i]

When I had surging it only happened when i gave the car a light amount of throttle

At least my in case I would assume it has something to do with running higher boost, probably bad diverter valves with high boost like someone said before..

[MeanMangoMan]

Originally Posted by MusclezMarinara

6MT or 6AT?

6AT That is exactly when I have surging, in 1st or 2nd with light amounts of throttle and high rpm.

[MeanMangoMan]

Originally Posted by scheherazade

Not sure, but AFAIK diverter valves stuck closed should make the car lean when you let off the throttle? (because they should have let air escape)

So I guess at higher boost, you have more air you should have let out - so you retain way too much.

In a fixed-fueling scenario this would make sense to me, but there's also the throttle closure to prevent excess air getting in, and usually fuel (in a gasoline engine) is metered to match air quantity so your AFR should remain on target.

I could also see you going rich if the valves open for no reason (you lose intake air pressure). But again, fuel should be metered to match air, so I don't see how this would work out.

Then again, I'm probably overlooking something (like where the air is measured).
Maybe someone with more knowledge can chime in...

-scheherazade

It is interesting you say that because I have been getting Lean Bank 1 Lean Bank 2 codes if I drive on long trips, 100 miles +.

[Chriztofor]

HPFP

[bob.oz.best]

MeanMangoMan, I'm not sure if you're active anymore(?), but did you ever get around to replacing the diverter valves, and did it work?

I just purchased an '07 335xi 6MT, experiencing the same surging/bucking in 1st/2nd at light throttle between 2k and 3k RPM. Sometimes more severe than others. Once I get up to 4k RPM, the car is silky smooth and has tons of power. FWIW, the service history shows it has already had the HPFP replaced.

[Bob20124]

I am experiencing throttle surging under highway cruising, constant throttle (not high boost condition). Tune or stock map no difference. Plugs, coils, and injectors replaced 10K ago.

[JamesHawk101]

Originally Posted by Bob20124

I am experiencing throttle surging under highway cruising, constant throttle (not high boost condition). Tune or stock map no difference. Plugs, coils, and injectors replaced 10K ago.

This was happening to me and I found out my JB4 was closing the wastegates way to far down in the rpm range causing the boost to surge in and out.

[speedster2333]

I get the surging a couple of times a month between 70-75mph 2400rpm once I give it a little throttle or cruise at 80 I have no problems. Its been doing this since I got the car in 2013 with stock, ppk and jb4.

[bob.oz.best]

Originally Posted by bob.oz.best

MeanMangoMan, I'm not sure if you're active anymore(?), but did you ever get around to replacing the diverter valves, and did it work?

I just purchased an '07 335xi 6MT, experiencing the same surging/bucking in 1st/2nd at light throttle between 2k and 3k RPM. Sometimes more severe than others. Once I get up to 4k RPM, the car is silky smooth and has tons of power. FWIW, the service history shows it has already had the HPFP replaced.

Looks like he's not active anymore. I decided to replace the diverter valves and it didn't do a damn thing to help the problem. It used to be intermittent, but now that it's getting colder outside (40F / 5C) it seems to do it all the time.

Anyone have any experience with this, including a diagnosis?

Once again: surging/bucking (almost feels like lugging) between 2-3k RPM, light to medium throttle, 1st and 2nd gear only.

Everything else is smooth as butter, and she has gobs of power when I step on it.

[Underground6t9]

check out midnight euro in Layton Ut

[galahad05]

Wonder if it's a dirty throttle body.
Or maybe even a dirty mass airflow sensor.

Problem is "surging" can have many causes--everything from what I mentioned above to bad throttle position sensor readings to occasional improper intake valve timing.

[Alienpsychologist]

This sounds like a fuel supply issue to me.

[timothy2001]

Years ago when I worked in a Service Dept and we had difficult intermittent drivability problems we would take a snap shot with a scan tool when experiencing the symptoms.

Wouldn't it make sense for those with a JB4 or Cobb to capture logs when this happens for analysis?

This is an old post but intermittent drivability problems are rough to diagnose.

[Me Happi]

Would love to keep this thread alive as I just purchased a 2010 328i sedan AT. Am experiencing intermittent surging and researching on the forum. Of course the previous owner never mentioned surging issue! But he did say he only purchased his 91 octane gasoline from Costco. I only use 91 octane Chevron and have only filled it up 3 times now since purchase date - 2/10/16. Wondering if it will correct the issue over time. Someone on this thread mentioned putting in Chevron Techron fuel injector cleaner concentrate. May try that if surging continues.

If anyone remedied the surging please post on this thread! Thanks.

[GODDSPD]

This is the only thread I can find with the same symptoms that I'm experiencing. Did anyone ever solve this bucking at low rpm issue?

[Air Drop]

Wow, I've been researching this 2,500-3,500rpm surge for over a year now. It seems there is no perfect answer and the problem happens often with these cars.

Folks have tried numerous things: valve cleanings, vacuum hose overhauls, replacing full ignition systems, replacing fuel injectors, VANOS cleaning, ECU re-map...nothing works for certain.

I'm beginning to believe that either O2 sensors or a dirty MAP (either in the charge pipe or intake manifold) may be the culprit.

Let me ask all of you, does the issue lessen/go away when the car is at full operating temperature?

[GODDSPD]

Originally Posted by Air Drop

Wow, I've been researching this 2,500-3,500rpm surge for over a year now. It seems there is no perfect answer and the problem happens often with these cars.

Folks have tried numerous things: valve cleanings, vacuum hose overhauls, replacing full ignition systems, replacing fuel injectors, VANOS cleaning, ECU re-map...nothing works for certain.

I'm beginning to believe that either O2 sensors or a dirty MAP (either in the charge pipe or intake manifold) may be the culprit.

Let me ask all of you, does the issue lessen/go away when the car is at full operating temperature?

If anything my gets worse as it gets warmer.

After carefully examining logs, mine is definitely related to the hpfp not increasing fuel demand with more throttle input causing it to buck and run lean.

I'm guessing it's the FCV on the HPFP but I don't think they sell them separately from the pump.

[halfmonkey]

Have any of you tried doing a walnut blast? If you've tried everything else and it didn't work maybe give that a try. Unfortunately as someone else mentioned, this could be from a number of areas so you basically have to just narrow it down. Good luck.

[sevco]

I didn't want to start another thread so here's my n54 headache..

bucks substantially with steady throttle 2500-3500ish rpm, regardless of gear. so its very hard to pull away from a stop smoothly.
Idle is almost always smooth, a small stumble from time to time.

I've attached my data log while running a e40 blend (MHD OTS) which seems to make it much worse but, I re-flashed a stock map and although far less noticeable there are still the same markers in the data log. the throttle, and timing correction going wonky. At the end of the log I gave it full throttle and it pulls solid, I found it odd that it shows 80% throttle while the pedal is 99.6% ?!

I have not done a through vac leak test, but there are no signs of it in the logs.

The car has the following all within the last 16k currently has 98k
MHD ots map for E40, liner throttle, 3.5bar map
walnut blast
new oem coil packs
new factory plugs
new factory fuel pumps HP and LP
Bosch 044 inline fuel pump
Tial BOV and ER charge pipe
3.5bar map
AMS fmic
ER downpipes
HAD a DP fix - has been removed
custom cat back
occ and rb pcv
Mmp inlets AFE filters
smfw Spec clutch



It had a stage 2 Dianan tune which the stealership promised me was the issue so I had them wipe that. Then said it was HPFP...then..so this has been going on since the car was stock + stage 2 Dinan

http://datazap.me/u/sevco/surging-an...rk=119-119-240

[Marcmann982]

I'm getting the same issues on my 07xi really surprised there's been no solution to this . Getting surging between 25-3000 rpm and at cruising speeds. Wot pulls fine but getting bucking and surging when cruising and its driving me bonkers. Is there really no fix for this?

[Monster900]

Originally Posted by Marcmann982

I'm getting the same issues on my 07xi really surprised there's been no solution to this . Getting surging between 25-3000 rpm and at cruising speeds. Wot pulls fine but getting bucking and surging when cruising and its driving me bonkers. Is there really no fix for this?

I'm getting exact same thing Let the troubleshooting begin.

[muncie21]

If anyone can post codes and/or logs, it would help this endeavor.