Anyone ever hear or experience this before???

[Xcelrrate]

I dont know the best was to describe what i am experiencing... but It only happens when the engine is under 2K rpms, and only while under load.

The first time I fet it, I thought I got a tank of bad gas or something along that line.

As I accelerate ((in any gear)(under 2k rpm)(<25% throttle)) I get this "Jolt" feeling.. notice I say jolt and not jolting. If jolting, I'd say the car was hesitating. but it's not that !!

To put it in the most basic elementary terms. Think of 2 gear wheels, on one of the gear wheel, its missing a tooth, so when the rotation comes to that point, it Jolts, skip, hesitate.... And it happens right at about 1500 rpms and 1900 rpms every time within these conditions((in any gear)(under 2k rpm)(<25% throttle))

It more or less throttle is applied, then all is good.

So it not a bad tank of gas, and I have gone through another 4 tanks.
Im not throwing any codes... and I dont want to bother with the stealers.

Thanks for any input.

[Seattle S65B40]

Originally Posted by Xcelrrate

As I accelerate ((in any gear)(under 2k rpm)(<25% throttle)) I get this "Jolt" feeling.. notice I say jolt and not jolting. If jolting, I'd say the car was hesitating. but it's not that !!

To put it in the most basic elementary terms. Think of 2 gear wheels, on one of the gear wheel, its missing a tooth, so when the rotation comes to that point, it Jolts, skip, hesitate.... And it happens right at about 1500 rpms and 1900 rpms every time within these conditions((in any gear)(under 2k rpm)(<25% throttle))

Even with your explanation, I can say that I have not experienced this. Unless you count when the car is "cold," in which case, it can be somewhat more inconsistent under the conditions you've described (low RPMs, low throttle, any gear).

[1sikbmr]

is your clutch slipping?

[Stainless 45]

Yeah I get this too- from day one. "Twitchy" is how I would describe it. Above 3k purrs along just fine, but, warm or cold, below 3k in 1st, 2nd or 3rd, it's a slight bucking. The only explanation I've been able to find it it's due to the "drive by wire"- there is so much power and this engine is so high strung it want to go full throttle. Light throttle and you feel every little adjustment. Curious too if anyone else has this, or a better diagnosis.

[Xcelrrate]

Originally Posted by Seattle S65B40

Even with your explanation, I can say that I have not experienced this. Unless you count when the car is "cold," in which case, it can be somewhat more inconsistent under the conditions you've described (low RPMs, low throttle, any gear).

Nope, car is at normal operating temp.

Originally Posted by 1sikbmr

is your clutch slipping?

Far from slipping..

I think any car would be far from drivable, if the clutch was slipping with low RPMs and low throttle

Originally Posted by Stainless 45

Yeah I get this too- from day one. "Twitchy" is how I would describe it. Above 3k purrs along just fine, but, warm or cold, below 3k in 1st, 2nd or 3rd, it's a slight bucking. The only explanation I've been able to find it it's due to the "drive by wire"- there is so much power and this engine is so high strung it want to go full throttle. Light throttle and you feel every little adjustment. Curious too if anyone else has this, or a better diagnosis.

Wow, from day one? Sorry to hear that. But Sorry, I dont like your explanation because this is something that just started recently. So at least in my case, my drive by wire has handled my high strung engine just fine...

I can deal with the problem/issue/thing... but its just not quite normal. No passenger has notice this "jolt" thing, and if they do, they'll probably think that I'm manipulating it myself..

oh well for now

[JohnnyRoaster]

It sounds to me like the DSC kicking in...

[stefan]

Do you have "power" turned on? It makes the throttle really jerky/stabby. Try with it off.

In terms of the "bucking" below 3K, sounds like you are coming off the throttle too quickly. Try to be more smooth, I think all powerful cars these days are like this. If I did that on my E46 M it would be pretty jerky.

To alleviate some of your concern, this really does not sound like a gearbox malfunction.

[Krozi]

I think everything is fine. These cars don't like low RPM.

[elp_jc]

Since it doesn't happen at larger throttle openings or under any other conditions, you're obviously looking at engine tuning. Remember the S65 doens't have a MAF, so low-rpm fueling is not perfect. When cold, it can buck like a bronco. And when hot, it can be jerky if engine is LUGGED.

I'm sure many of us would experience the same issues, but I never lug my engine like that. I've never experienced any issues at those rpm in 2nd or 3rd, but the rare few times I've accelerated from those rpm when anticipating a light to turn green but another one in front is red (no need to accelerate), I maintain speed at less than 25% throttle until above 2K. If I have to accelerate quicker, I always downshift first.

Bottom line is there's no problem man. Just adjust your driving habits. And your engine will thank you for it . If you don't like to shift, you should have bought an automatic . Take care.

[sameh]

Originally Posted by Krozi

I think everything is fine. These cars don't like low RPM.

Agree with you. BMW should put this statement on the visor "your car does NOT like low RPM"

[Xcelrrate]

Originally Posted by JohnnyRoaster

It sounds to me like the DSC kicking in...

How and why?

Originally Posted by stefan

Do you have "power" turned on? It makes the throttle really jerky/stabby. Try with it off.

In terms of the "bucking" below 3K, sounds like you are coming off the throttle too quickly. Try to be more smooth, I think all powerful cars these days are like this. If I did that on my E46 M it would be pretty jerky.

To alleviate some of your concern, this really does not sound like a gearbox malfunction.

Power is off, and makes no difference in terms of this "jolt"
I know what you mean with the jerky-ness, I too had a E46 M3

I never exactly thought of it as a tranny issue, other than it jolt precisely @ 1500k & 1900k rpms.

Originally Posted by Krozi

I think everything is fine. These cars don't like low RPM.

Originally Posted by elp_jc

Since it doesn't happen at larger throttle openings or under any other conditions, you're obviously looking at engine tuning. Remember the S65 doens't have a MAF, so low-rpm fueling is not perfect. When cold, it can buck like a bronco. And when hot, it can be jerky if engine is LUGGED.

I'm sure many of us would experience the same issues, but I never lug my engine like that. I've never experienced any issues at those rpm in 2nd or 3rd, but the rare few times I've accelerated from those rpm, I do it at less than 25% throttle until above 2K. If I have to accelerate quicker, always downshift.

Bottom line is there's no problem man. Just adjust your driving habits. And your engine will thank you for it . If you don't like to shift, you should have bought an automatic . Take care.

I like your post by far, sounds most logical to me in regards to the lack of a MAF.

What do you mean by LUGGED?

nothing is being lugged if my car was rolling at 10mph, gently engage the clutch in 2nd, and gently accelerate @ 20% throttle.

I take your 3rd paragraph in offense but ... I dont see any problems in my driving habits. I speak of an issue that was of no existence to oh why is my car doing this?
My engine does thank me, for my religious 5K oil change intervals; oil analysis says engine is healthy and strong..
I love to shift! please dont let my low post count fool you. I am by far not new to ///M Cars! Having my first E46 Tiag M3 (SMG) back in '02

btw, I live in Vegas, so my car has been through 30 degrees to 117 degrees so hi and low temps are not new to this car.


Thank you all for all your great input

[elp_jc]

Originally Posted by Xcelrrate

What do you mean by LUGGED?
I take your 3rd paragraph in offense but ... I dont see any problems in my driving habits.

Well, I was going to respond with your following quote:

Originally Posted by Xcelrrate

As I accelerate ((in any gear)(under 2k rpm)(<25% throttle))

Then I noticed the '<', when my post was based on '>'; Oops . Sorry buddy. So never mind the 'offensive' comments .

As far as lugging the engine, I made the comment based on '(in any gear)'. You'd obviously be fine in 2nd. In 3rd, you'd definitely be lugging the engine at 1.5K rpm and 25% throttle, but less so at 1.9K rpm. And it gets worse on higher gears. Besides, the engine has almost no power when being lugged so no need to do that. But if you're just slowing down anticipating a green light where there's a red one ahead, you can feather the throttle in 3rd (level road) at those rpm without lugging the engine. Take care, and sorry again for the confusion .

[stefan]

Originally Posted by Xcelrrate

Power is off, and makes no difference in terms of this "jolt"
I know what you mean with the jerky-ness, I too had a E46 M3

I never exactly thought of it as a tranny issue, other than it jolt precisely @ 1500k & 1900k rpms.

Well then if you have had the E46 M you must know exactly what I'm talking about .. so it can't be that then! Perhaps just a tuning issue? But that said tuning is pretty uniform in these cars. Not sure if it was mentioned, but are you at high altitude? Is the fuel you are using an ethanol blend (e.g., 91 uprated to 94 with ethanol addition)?

I'm really just throwing things out there because other than what I've described (which you have actually experienced), it's hard to know what you mean... can you take a video of your tach?

[Titanium Silver]

DSC or 6MT?

Use your clutch if your RPMs are super low. Everyone with the 6MT complains about jerkiness and difficult 1 > 2 shits and 3 > 2 shifts. What's up with this? I don't have any problems. Took about a week of driving to get used to the clutch (engagement is a little high compared to other cars). I am not going to remove any clutch springs or get a SSK. The car is completely fine stock. Shifting is smooth and no weird issues.

If you have DCT, this is probably normal. However, I can't comment on this. Not trying to start another DCT vs 6MT thread. There are more than plenty on this forum.

[Dackelone]

Sounds like a bad coil pack or missfire. ?

[Xcelrrate]

Originally Posted by Titanium Silver

DSC or 6MT?

Use your clutch if your RPMs are super low. Everyone with the 6MT complains about jerkiness and difficult 1 > 2 shits and 3 > 2 shifts. What's up with this? I don't have any problems. Took about a week of driving to get used to the clutch (engagement is a little high compared to other cars). I am not going to remove any clutch springs or get a SSK. The car is completely fine stock. Shifting is smooth and no weird issues.

If you have DCT, this is probably normal. However, I can't comment on this. Not trying to start another DCT vs 6MT thread. There are more than plenty on this forum.

HUH WHAT? What do you mean DSC or 6MT ?

I wasn't complaining about difficult shifting! I'm IN GEAR accelerating and the JOLT is AT 1500k rpm and 1900k rpm (No shifting involved)


BTW, you must not have driven a car with an SSK! Try to find a fellow member locally that has, say a UUC ssk It might just make you feel that your STOCK shifter is loose in terms of play. Not even gonna get into the whole shorter throw between gears. But if you dont know what we're talking about here, then nevermind.

Originally Posted by Dackelone

Sounds like a bad coil pack or missfire. ?

I'm sure that would throw a code...

[Xcelrrate]

Originally Posted by elp_jc

Well, I was going to respond with your following quote:

Then I noticed the '<', when my post was based on '>'; Oops . Sorry buddy. So never mind the 'offensive' comments .

Take care, and sorry again for the confusion .

No worries

Thanks for your previous post though!

[Dackelone]

Originally Posted by Xcelrrate

I'm sure that would throw a code...

You are thinking like a BMW tech. No fault code no problem found (NPF).

You need to start thinking like a mechanic.

[Xcelrrate]

Originally Posted by Dackelone

You are thinking like a BMW tech. No fault code no problem found (NPF).

You need to start thinking like a mechanic.

How would YOU be thinking about this situation?

[ersin]

I can't say I've ever experienced that kind of behavior in my car. It is a little rough when cold but I don't think I've experienced that even when cold. I know you don't want to go to the dealer but they might be the only ones who can figure this out, if anyone. Perhaps there's an independent shop in your area that specializes in BMWs, or European cars?

Sorry, I can't be any more help but I've never heard of this before. Good luck.


Cheers.

[2swift]

I've been getting the bucking/hesitation since day one too. Kinda embarrassing with people in the car since they think I'm about to stall but, yeah, just put more throttle and the jerk goes away. Like krozi said, this car just doesn't like low rpm's!

[ersin]

Ok, I just checked again. There's a train track down the hill I go over at 5 - 10 mph and in 2nd gear. I accelerate out from about 1K - 2K rpm -- no problem, just as smooth as ever. Other than this I rarely run slower than 2K rpm. So it sounds to me like this "jolt" that some of you seem to have is not normal.


Cheers.