[mspohn]

I have a 2016 F31 with the track handling package, and thererfore, the variable steering rack.

The steering is awful. Way over-boosted "on-center" and inconsistent delivery of assist. Every shop i take it to (that knows what these cars should feel like) thinks the rack is broken. The car is seriously scary to drive at speed in traffic because of the inconsistent boosting of power assist that comes during changing lanes and micro steering movements.

The entire system has been replaced under warranty to try and remedy it to no avail...the rack, all modules, the strut assemblies, the steering shaft...you name it...

So...the only thing I can think is, why can't the steering module be re-coded to match or mimic the parameters in M3 of the same year?

Thanks!!
Matt

[njdangelo]

I too am VERY interested in this as I have the same issues the THP on my 340. Steering rack replaced already as well. The steering is very unpredictable sometimes and there is a huge flat spot on center as well. Hoping someone has the answer!

[mspohn]

I actually can't believe how bad this is and my experience with BMW has been so bad that I will never buy a newer BMW from a dealer again. I've gone around in circles with BMW corporate who straight said they will not help, they will not send a tech, and they also flat out said that no shop foreman would request BMW's support because it makes the shop look bad in BMW's eyes.

[njdangelo]

Thats unfortunate, i have had great experience with my local BMW dealeraship. I think I'm going to call Dinan on Monday and see what they say. If anyone knows the ins and outs of bmw coding it should be them. Maybe Active Autowerk too

[dmaxdmax]

Just tossing this out in case, but could this be related to something like the voltage regulator in the alt or some other electrical issue, external to the steering?

[mspohn]

Originally Posted by dmaxdmax

Just tossing this out in case, but could this be related to something like the voltage regulator in the alt or some other electrical issue, external to the steering?

Are you suggesting bad voltage values to the computer is causing an issue? I think it would be more likely that bad inputs are coming in from other steering/suspension senors.

[Skyhigh]

Not really sure what you are talking about. The VSS certainly takes a day or two to get used to, but I find it good. Not that I wouldn't be able to live without it, but it is certainly an advantage.

Obviously if there is something wrong in yours, that's a different story.
But the rack itself is not "code-able", it is a mechanical translation. In sport, the required efforts for turning are increased to make it more precise, but if you dislike that, you can disable it from Sport mode. Apart from that - it is as is...

[mspohn]

Originally Posted by Skyhigh

Not really sure what you are talking about. The VSS certainly takes a day or two to get used to, but I find it good. Not that I wouldn't be able to live without it, but it is certainly an advantage.

Obviously if there is something wrong in yours, that's a different story.
But the rack itself is not "code-able", it is a mechanical translation. In sport, the required efforts for turning are increased to make it more precise, but if you dislike that, you can disable it from Sport mode. Apart from that - it is as is...

It is not purely "mechanical translation" as you put it. The power assist comes from an electric motor, rather than hydraulic as is traditional. This motor is "told' how much assistance to give based on the drive settings and a number of inputs from various sensors about speed, yaw, slip, etc. This is coding that interprets the data and then decides how much to assist.

What I am suggesting is that there is an issue here, as all the mechanical systems check out. I suspect if nothing feels wrong with yours, you have a different set of coding (which i'd love to find out as you have a euro-car), or don't have a proper baseline for what it should feel like.

[Skyhigh]

I am not sure you are correct.
My understanding is that the only input to the VSS is speed. And the only actively changing element is the electirc assistance. This said, the rotational movement of the steering wheel is always translated into the same turn, irrespective of how much force you need for it. Meaning if you turn the wheel with 30 degrees from straight, you will always get the same response from the wheels (this is the purely mechanical element).

Now, as I said I am not 100% sure about the above, but if I am correct, that's where I don't understand what you are actually complaining about? The variable force required to turn X degrees?
Again - my understanding is that there are no "sonsors" at play here, only speed input. The higher the speed, the less sensitive the wheel (less assistance from the electrical motor). What would you like to code?

And just for the record - there are no codding settings for the VSS as far as I have seen. Meaning it is all hard-coded software that is unlikely to be different on yours in comparison to all others, at least from the same ModelYear.

[Skyhigh]

P.s. here the official BMW description, which supports my understanding above:

The variable sport steering increases the steering angle of the front wheels at large steering wheel angles, e.g., in tight curves or when parking. Steering becomes more direct.

It also varies the force required to turn the wheels in accordance with the vehicle speed.

This results in a sporty steering response. In addition, it becomes easier to steer during parking and maneuvering.

Servotronic

The concept The Servotronic varies the steering force required to turn the wheels in accordance with the vehicle speed. At low speeds, the steering force is strongly supported, i. e. during steering, low force is required. As the speed increases, the assistance of the steering force is reduced.

Furthermore, the steering force adapts according to the driving program, so that a direct, sporty feel and/or comfortable steering is conveyed.

[Danddd]

I don't understand how BMW can not get the steering feel correct. Both Cadillac and Porsche vehicles with electric steering have feel and are superior to BMW in this regard. And BMW seems to go forward with more pricey tech than ultimate driving experience...unless it's the tech.

[amancuso]

Steering box in the M3 shows part number 32107852660. The one for your car shows 32106881072.

[dmaxdmax]

Originally Posted by mspohn

Are you suggesting bad voltage values to the computer is causing an issue? I think it would be more likely that bad inputs are coming in from other steering/suspension senors.

It is likely that a bad alt or battery would signal some code, though given it's electric steering, it'd take a lot of power to steer when there's a lot of load...slow speed, high speed maneuver. I don't know the car that well yet, but I'd check the voltages...easy enough to eliminate as an issue.

[willem-jan]

I have a F30 with VSS (option 2vl) as well. Dont like it at all. It is very sticky in the center. I even doubt if the rack is ok. Already replaced the thrust piece (the repair set) to fix the noise issue. But this didn't fix the sticky steering. Any body experience with retrofitting an M3 rack?

[Wires]

My 2016 340 has always had a dead spot at center, which became MUCH worse in sport mode.

Another thread mentioned a software update for steering: SIB 32-03-19

I took the car in for her last free service yesterday, mentioned my issue and referenced this update. Car came back loaded with the update, and no more dead spot at center. MUCH better experience than previous.

[ezhik]

I can shed 'some' light on the subject, but it's still very much an open question for me:

Is there an editable table of steering assist weights on an F30 335i with EPS hydro servotronic steering?

Knowns:

- Steering effort is proportional to speed (weight increases with speed in my observations, and pretty much everyone else is in agreement. It's also documented officially page 33 (enter '33' into the page selector on the scribd panel)

- Toggling through the gimmick driving modes yields different curves for the above behaviour, comfort being the lightest, sport being almost passable for decent steering effort

What I want:

- Replicate steering effort of the older platforms: minimal assist at driveway speed ( it's a modern car after all) and no assist at anything over driveway speeds)
- Same settings under all the driving modes

I've been chasing this one on the forums for a while. I also own an 07 E90 328, and the valving between the P/S fluid and the hydro rack there is an absolute delight. I'm aware of all the marketing and supply/demand that BMW went through, and that driving in general is on its way out, but I'm an engineer, and I'll solve problems *while* complaining about them, so there's got to be a way to do this.


The developer in me says this:

I'm led to believe that the weights are described somewhere, since the car applies variable weight to the EPS motor under these observed conditions:

toggling sport | comfort at low speed creates a noticeable (albeit slight) difference in steering effort
comparing steering effort at 20mph vs 80mph steering effort becomes progressively heavier
From those two findings, I'm certain there's a couple scalars, or a table of arbitrary weights that eventually correspond to final calculations that dictate motor torque on the EPS itself.

I've considered these three things:

Disconnect the EPS module and steer with no PS (worth trying, seems straightforward, probably not without CELs, and will likely be too heavy.)
-- Actually went and did this, it's too heavy
-- Someone said to pull the plug on the incoming torque sensor from the rack's motor control module, so there may be hope there (will try that soon enough)

Install a considerably large resistor to limit power to the electric motor
- seems to be impractical, as at least some documentation on EPS modules on other platforms seems to consume 10-1kW (page 16)
-1kw resistor in the engine bay, while a fun practical idea, is not something I can comfortably live with day-to-day.

-- Followed up on this one too, the signal is pwm and controls the motor as a combo input of DME curves against the torque sensor inputs, so current-limiting will just make the motor inoperable.


Bonus Round: Change the gear ratio in the EPS box. seems the driving gear could be replaced with something smaller, reducing torque delivered to the final output, but I'd likely need to have one custom milled, and have to drop the rack, rebuild, etc. Not terribly fun.

Being that the system itself is pretty darn clean and superior to the hydro racks, I'd like to solve this with software, because it's the offender. If we can change a set of consts to make steering weight heavier (and constant) across all the driving modes, and conditions, that'd be amazing!! Even bumping the current values by some arbitrary (heavier) amount would be more than enough!

[harkes]

Was there any progress on this? I do not have the problem that OP has but I would like to code away the over weighted steering in the Sport modes.

[Skyhigh]

No need to "code it off", disable it under the settings of Sport mode if you dislike it.

[chakatrain]

Originally Posted by Wires

My 2016 340 has always had a dead spot at center, which became MUCH worse in sport mode.

Another thread mentioned a software update for steering: SIB 32-03-19

I took the car in for her last free service yesterday, mentioned my issue and referenced this update. Car came back loaded with the update, and no more dead spot at center. MUCH better experience than previous.

I’ve been looking for the specific SIB number about this. Thank you very much.

Is there a way for me to see if a SIB has been updated on my car? Can a third-party reputable local shop do this update or do I have to go to a dealer?

Thanks!

[Wires]

That is a great question. I'm assuming you'd need a BMW certified shop since they probably need the BMW ISTA software to check versions. Maybe you can check with Esys as well?

[chakatrain]

I’ll call my local shop (BMW specialists) and report back on what they can do.

[Danddd]

Taking my '16 F31 on Thursday for an oil change at Bill Jacobs BMW in Naperville, IL and am going to check on this software update. I'll report back.