[nadthomas]

For several months now, I have noticed that under certain conditions I will get a pretty bad dip in power around 3500RPM almost like traction control is kicking in. I mostly notice it when merging on the freeway from a sweeping on ramp. I have found I can specifically reproduce it if I'm in 3rd or 4th gear cruising at around 2000RPM, and then go WOT. When doing that pretty much every time I experience the loss of power just before 3500RPM, I then see a slight dip in RPMS, and then after a second or two the car will continue to accelerate like normal. I have done this with traction control completely off to verify that its not traction control.

I do have a CEL for thermostat stuck open, which I will be replacing this weekend, but I assume that would have no impact on this issue. I'm at 62k miles so I did replace the spark plug a few weeks ago, but that did not change anything with this issue. I was also running the Dinantronics Sport Tunner on the 93 octane setting for almost 2 years without issue, but disconnected it a couple of months ago when I started to notice this issue.

Any thoughts, or things I should test would be appreciated. I did recently get a Foxwell NT510 which is supposed to be identical to the Schwaben Scan tool, but I haven't had time to play with it yet.

[rjd_F30]

If you're going WOT at 2k rpms you're seriously lugging the engine. I wouldn't be surprised if a pillow of black smoke comes out the back because the car dumps fuel to prevent leaning out/detonation (LSPI, low speed-pre ignition). Especially considering there's no other problems, I would suspect you don't have an issue, you're just expecting the car to do something it can't do. If you want to accelerate, grab a lower gear. These videos explains it well:

[nadthomas]

Been driving a manual for 15 years, I'm well aware of lugging the engine.

I was just giving an example of how I can force the issue. It doesn't have to go quite as low as 2k rpm for it to happen, and there are plenty of situation in daily driving that I get stuck behind slow traffic in 2nd gear and the traffic will open up, so I go WOT or I guess more specifically I roll into it and end up WOT and I will still experience the power drop around 3500RPM. In those situations, I'm not going to drop to 1st when I'm already rolling(except maybe very rare cases at the track).

This is also not something that I experience in my first 2.5 years of owning the car. It only started happening in the past couple of months.

[rjd_F30]

Originally Posted by nadthomas

Been driving a manual for 15 years, I'm well aware of lugging the engine.

I was just giving an example of how I can force the issue. It doesn't have to go quite as low as 2k rpm for it to happen, and there are plenty of situation in daily driving that I get stuck behind slow traffic in 2nd gear and the traffic will open up, so I go WOT or I guess more specifically I roll into it and end up WOT and I will still experience the power drop around 3500RPM. In those situations, I'm not going to drop to 1st when I'm already rolling(except maybe very rare cases at the track).

This is also not something that I experience in my first 2.5 years of owning the car. It only started happening in the past couple of months.

Ok gotcha. I'm sure you can understand why you're original post made me think you were just lugging the engine though. Didn't mean to imply you didn't know what you were doing or anything like that lol.

Is it an abrupt cut in power like the car breaks up, or does it just feel slower or more sluggish than usual?

[nadthomas]

No problem.

It literally feels like I lift off the throttle, and then get back on it.

I was playing around with my Foxwell at lunch try to get some data. I have a DTC 480134 ICM: Direction of travel cannot be determine. Which from what I'm reading could be a ABS/Wheel speed sensor going bad. I suppose if the car is losing communication with a wheel it might freak out a little bit and pull power, but that seems a bit extreme. Also, I can't identify which wheel would have the faulty sensor, since when I look at the live data for wheel speed it all looks good, and the scanner is reporting 100% communication to all wheel. Including while I'm reproducing the actual power loss, so I am not really sure I am buying my own theory.

I also did a monitor of the Engine Speed, Pedal Sensor Position, and Throttle Valve Opening Angle. It was a little hard to watch while driving, but when I go WOT it shows the Pedal Sensor Position at 100% the entire time, and the Engine Speed reflects exactly what I described previous, but the Throttle Valve Opening Angle does go to 100%, and then drops down during the power loss before slowly increasing again. Not sure if the Throttle Valve changing is the cause, or just a side affect of whatever is actually happening.

[rjd_F30]

Originally Posted by nadthomas

No problem.

It literally feels like I lift off the throttle, and then get back on it.

I was playing around with my Foxwell at lunch try to get some data. I have a DTC 480134 ICM: Direction of travel cannot be determine. Which from what I'm reading could be a ABS/Wheel speed sensor going bad. I suppose if the car is losing communication with a wheel it might freak out a little bit and pull power, but that seems a bit extreme. Also, I can't identify which wheel would have the faulty sensor, since when I look at the live data for wheel speed it all looks good, and the scanner is reporting 100% communication to all wheel. Including while I'm reproducing the actual power loss, so I am not really sure I am buying my own theory.

I also did a monitor of the Engine Speed, Pedal Sensor Position, and Throttle Valve Opening Angle. It was a little hard to watch while driving, but when I go WOT it shows the Pedal Sensor Position at 100% the entire time, and the Engine Speed reflects exactly what I described previous, but the Throttle Valve Opening Angle does go to 100%, and then drops down during the power loss before slowly increasing again. Not sure if the Throttle Valve changing is the cause, or just a side affect of whatever is actually happening.

Yah I doubt a wheel speed sensor would be a source of the issue here.

However, a throttle closure seems like it could a problem. I know throttle closures are a big issue when tuning the B58, and while I haven't really heard of it happening on an N20, I don't see why it couldn't be a possibility. From what I understand, throttle closures can be cause by either traction control (which you already addressed) or overboost. Since you removed your Dinan sport I don't see why you would be overboosting, but it can't hurt to run a log and check if you have something that can record a datalog.

[fiveohwblow]

Originally Posted by nadthomas

For several months now, I have noticed that under certain conditions I will get a pretty bad dip in power around 3500RPM almost like traction control is kicking in. I mostly notice it when merging on the freeway from a sweeping on ramp. I have found I can specifically reproduce it if I'm in 3rd or 4th gear cruising at around 2000RPM, and then go WOT. When doing that pretty much every time I experience the loss of power just before 3500RPM, I then see a slight dip in RPMS, and then after a second or two the car will continue to accelerate like normal. I have done this with traction control completely off to verify that its not traction control.

I do have a CEL for thermostat stuck open, which I will be replacing this weekend, but I assume that would have no impact on this issue. I'm at 62k miles so I did replace the spark plug a few weeks ago, but that did not change anything with this issue. I was also running the Dinantronics Sport Tunner on the 93 octane setting for almost 2 years without issue, but disconnected it a couple of months ago when I started to notice this issue.

Any thoughts, or things I should test would be appreciated. I did recently get a Foxwell NT510 which is supposed to be identical to the Schwaben Scan tool, but I haven't had time to play with it yet.

FYI, off topic but my 2013 is out of warranty and when I shared the thermostat problem with my friend who is a tech at BMW, he jokingly said "you aren't doing that yourself, are you?!"

Needless to say, I recommend you call a service adviser as this was covered post warranty for me last month, free of charge.

[nadthomas]

Originally Posted by rjdnyy224

Since you removed your Dinan sport I don't see why you would be overboosting, but it can't hurt to run a log and check if you have something that can record a datalog.

I assume that the Foxwell Scanner should be able to log overboost, but not sure how yet.

FYI, off topic but my 2013 is out of warranty and when I shared the thermostat problem with my friend who is a tech at BMW, he jokingly said "you aren't doing that yourself, are you?!"

Needless to say, I recommend you call a service adviser as this was covered post warranty for me last month, free of charge.

Good to know. Although, I already ordered the new thermostat, and I my local dealership is hit or miss. So, I'll just do it myself. Watched a YouTube video of the job and it looks pretty easy.

[rjd_F30]

Originally Posted by nadthomas

I assume that the Foxwell Scanner should be able to log overboost, but not sure how yet.



Good to know. Although, I already ordered the new thermostat, and I my local dealership is hit or miss. So, I'll just do it myself. Watched a YouTube video of the job and it looks pretty easy.

The Foxwell, being a code reader, isn't capable of datalogging, but I'm not sure whether or not it would throw a code if the car overboosts. I mean an actual datalog of engine parameters during a pull.

[nadthomas]

The Foxwell NT510 is more then just a code reader. It says its able to request and record live sensor data. So, I believe I should be able to data log things.

Agreed that I fully expected this issue to throw a code. If it was an issue with the throttle position sensor itself, I would have expected a code, and if it was an situation where the ecu felt it needed to close the throttle body to save the motor I would have expected a code too.

[rjd_F30]

Originally Posted by nadthomas

The Foxwell NT510 is more then just a code reader. It says its able to request and record live sensor data. So, I believe I should be able to data log things.

Agreed that I fully expected this issue to throw a code. If it was an issue with the throttle position sensor itself, I would have expected a code, and if it was an situation where the ecu felt it needed to close the throttle body to save the motor I would have expected a code too.

Didn't know that about Foxwell, I would put that feature to use then.

And agree and agree on your last statement, I would expect it throw a code, but I've had worse things happen that didn't throw codes, so you never know.

[f30nick]

Originally Posted by nadthomas

For several months now, I have noticed that under certain conditions I will get a pretty bad dip in power around 3500RPM almost like traction control is kicking in. I mostly notice it when merging on the freeway from a sweeping on ramp. I have found I can specifically reproduce it if I'm in 3rd or 4th gear cruising at around 2000RPM, and then go WOT. When doing that pretty much every time I experience the loss of power just before 3500RPM, I then see a slight dip in RPMS, and then after a second or two the car will continue to accelerate like normal. I have done this with traction control completely off to verify that its not traction control.

I do have a CEL for thermostat stuck open, which I will be replacing this weekend, but I assume that would have no impact on this issue. I'm at 62k miles so I did replace the spark plug a few weeks ago, but that did not change anything with this issue. I was also running the Dinantronics Sport Tunner on the 93 octane setting for almost 2 years without issue, but disconnected it a couple of months ago when I started to notice this issue.

Any thoughts, or things I should test would be appreciated. I did recently get a Foxwell NT510 which is supposed to be identical to the Schwaben Scan tool, but I haven't had time to play with it yet.

+1 Am experiencing the same issue

If I am in a high gear low in the RPMs, I experience the same rise in RPMs and then sudden dip. Also running the dinan sport tune. Last oil change, noticed that the car was also burning oil. Will be bringing the car in soon.

[f30nick]

Turns out it was the clutch slipping.

[CandyRedRC46]

So the clutch slips and then some how the ECU see this and pulls power?

[rjd_F30]

Originally Posted by f30nick

Turns out it was the clutch slipping.

Hmmm... That makes perfect sense considering you said it was like you were lifting off the throttle... Glad you found it.

[CandyRedRC46]

Originally Posted by rjdnyy224

Hmmm... That makes perfect sense considering you said it was like you were lifting off the throttle... Glad you found it.

not really, he said the rpms dipped... typically with a slipping clutch the rpms would jump up.

[rjd_F30]

Originally Posted by CandyRedRC46

not really, he said the rpms dipped... typically with a slipping clutch the rpms would jump up.

Hmmm you're right didn't see that part, was just going off him saying it felt like he lifted/the car stops accelerating which would make sense, but if you stay on the gas once the clutch slips you're right the rpms would go up. I would guess though, if this were me and I were accelerating and the car stopped accelerating or if there were an issue I would immediately lift, maybe that's what happened. But even then you wouldn't be able to react quick enough to not see a quick jump in rpms before you could get off the gas... idk lol

[f30nick]

Originally Posted by CandyRedRC46

not really, he said the rpms dipped... typically with a slipping clutch the rpms would jump up.

RPMs did surge upwards then dip. Maybe OP didn't mention, however that was the scenario in my case.

[nadthomas]

Originally Posted by f30nick

RPMs did surge upwards then dip. Maybe OP didn't mention, however that was the scenario in my case.

Nope, in my case there is no surge in RPMs. The tach and sound of engine are completely normal build, and then it dips. Your right in that initially I had a tendency to lift slightly when this would happen, but since it has become "normal" at this point I don't lift, and certainly didn't lift when I was monitoring the throttle input with my Foxwell. I'm pretty confident its not clutch slip.

I did replace the thermostat a couple of weeks ago, and cleared all codes. The CEL has been off sense, but the hesitation issue persists. I have been busy with an oil pressure issue on my wife's Yukon Denali recently, so I haven't had time to explore this further. I should be wrapping that project up soon, so I'll be looking into this issue again in the next couple of weeks.

[rjd_F30]

Originally Posted by nadthomas

Nope, in my case there is no surge in RPMs. The tach and sound of engine are completely normal build, and then it dips. Your right in that initially I had a tendency to lift slightly when this would happen, but since it has become "normal" at this point I don't lift, and certainly didn't lift when I was monitoring the throttle input with my Foxwell. I'm pretty confident its not clutch slip.

I did replace the thermostat a couple of weeks ago, and cleared all codes. The CEL has been off sense, but the hesitation issue persists. I have been busy with an oil pressure issue on my wife's Yukon Denali recently, so I haven't had time to explore this further. I should be wrapping that project up soon, so I'll be looking into this issue again in the next couple of weeks.

Oohh I mistook you for f30nick, my mistake

[D041987]

To test the clutch go up a hill and put it in a lower gear like 4th and be around 3k and go WOT trying to go up hill. If clutch is bad it will slip and engine will stutter and RPM will rise and dip.

If all is well after repeated attempts, i would than monitor boost levels and check wastegate duty cycle, as the oem plastic DV valve can leak with age and give erratic boost spikes. Than you would check the charge pipe or smoke the system to find any leaks at connection points.

[Wahla]

Originally Posted by f30nick

+1 Am experiencing the same issue

If I am in a high gear low in the RPMs, I experience the same rise in RPMs and then sudden dip. Also running the dinan sport tune. Last oil change, noticed that the car was also burning oil. Will be bringing the car in soon.

Did the car stop burning oil after replacing the clutch? I have the same issue, car burns oil (about 6.5dl/1000km) and slipping clutch.