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03-07-2021, 05:46 PM | #23 |
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Found out yesterday my Foxwell reader can show steering parameters like steering angle, load, etc Perhaps a reader like that might show something.
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03-07-2021, 11:15 PM | #24 | |
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Yes, i have used Protool to look ar steering angle and torque sensor. TQ sensor shows very minor torque applied even when not turning wheel, but the amount is so small thad i believe it does not change anything. |
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03-09-2021, 09:27 PM | #25 |
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Drives: BMW E89 Z4 sDrive 35i
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i had similar experience (rocking front-rear and left-right) with a shitty, badly maintained old merc back in the early '90s and eventually found out it was caused by the badly leaked dampers. the springs were doing all the job so it rocked like jumping in trampoline.
but as you have mentioned all dampers are changed, i would guess the car's ecu may thinking you have the electronic damper system and expecting the dampers are responding (stiffer) as they should (in non-standard mode) but they are not so something like abs/powersteering intervened. |
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03-21-2021, 10:51 AM | #26 |
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The car never had electronic dampers. Ordinary ones.
Try`d one more time spacers, put 15m spacers up front and Since no more ideas, i changed the one front shock to stock one to see is there some difference. No,this does not stop this rocking. I have changed EPS parameters multiple times with Protool while on the road. Steering is changing , form extreme unstable to just unstable. But , to say that car is stable will be far from reality. Above 100km/h it is so unstable that slightest movement of steering make the car wander all over the road (no the dsc is or abs is not kicking in, just wandering). From feel it is like some rubber is between steering wheel and wheels itself. On low speeds everything seems very normal,stable, flat cornering. So guys tell me, how your car feels to drive 60-100-150mph? |
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03-21-2021, 08:19 PM | #27 |
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from my point of view "rocking" should be suspension shock absorber issue. anyway, when you say the car wandering at higher speed that reminds me my peugeot 205 with front toe-in setting and was horrible to drive. was told about rear wheel drive vehicles need front toe-in and front toe-out for front wheel drive vehicles.
in that case why not try the toe setting yourself a very tiny little bit at a time say 1/8 of a turn on only one side steering rod each time (of course you have to record down what you have done each time). it is a simple test out you can diy easily. |
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03-22-2021, 04:20 AM | #28 | |
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I have try`d that also before. But i was turning BOTH sides L and R , also i turned these not 1/8 of a turn but 1/2 and even full 3 turns. The results ? Toe in = sharp steering & very unstable, rocking L R L ater sharp input. Toe out = very slow turning, stable after sharp input, to my feel weight transfer does not actually happen much. This is strange to me, as literature states opposite. When aligned back to stock settings i have tryd slalom some distance on level durface. Inside of front tires is warmer than outside, observed by palm feel. Do not know is it normal, was thinking that outside must be warmer. |
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03-27-2021, 01:29 PM | #29 |
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I see you have changed everything from tires, shocks, steering rack, and other parts. Have you checked the wheels for damage, like cracks, and breakage. Has your Z been in any collisions? Bent or broken frame parts? I know tie rods would do this on my E36. (long gone) This is a real puzzle, and I'll watch this thread for my own interest. I drive a 2009 E89.
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03-27-2021, 02:22 PM | #30 | |
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Wheels are perfect. No collisions.Everything tight and fit except steering feel. |
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04-04-2021, 04:34 AM | #32 | |
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I believe this is steering issue,but if EPS change gave no results i have no clue. |
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04-11-2021, 12:00 AM | #33 |
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08-18-2022, 03:09 AM | #38 |
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Did you manage to find out what was the problem?
I have the same issue for my '13 E89 28i. The front starts randomly to oscillate from left to right at speeds over 120kph. The higher the speed the more worse it gets. I also find it more stable in COMFORT MODE then in SPORT & SPORT+ mode. I just checked the electronic adaptive dampers in shop and they are between 85%-91% OK. From what I read here the EPS uses sensors to identify the position of the steering rack and tries to dampen any unwanted oscillations using the EPS motor. Maybe we have a faulty sensor inside the EPS unit which is feeding faulty data to the EPS ECU. This would also confirm why the car feels different in COMFORT/SPORT/SPORT+ as the ECU will output different levels of adjustments depending on the mode we are in. I am also waiting for a new set of Continental SC7 for the fronts to see if anything changes. |
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08-18-2022, 03:24 AM | #39 | |
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08-18-2022, 05:13 AM | #40 |
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You may try and inspect steering angle sensor behind the steering wheel...
Mine had come loose at some point. There is a round retaining clip ring that holds whole steering angle sensor together... Mine had popped off and all was loose inside... Steering angle sensor works as and optical sensor reading lines on a disc through a camera to identify steering position. Now imagine when the alignment is loose and out of spec and sensor gets wierd readings... or dust has got inside of it to mess with the readings... My steering felt a bit wierd at one point aswell.. when i took my steering wheel off... interior steering column plastics off and removed that steering angle sensor module i noticed it was all in loose parts wobbling around. and i had no error messages or lights that would indicate anything being wrong with it. Put everything back together... secured with the retaining ring that had come loose... reinstalled it. And i havent had any wierd steering issues since. on how steering angle sensor works: https://bimmerist.com/bmw-e8x-e9x-st...r-calibration/ I used newtis.info manuals for steering angle sensor replacement to help me take things apart and put back together.
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08-18-2022, 06:28 AM | #41 |
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Interesting ..thanks for sharing that,,
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03-06-2023, 02:01 PM | #44 |
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I had a similar problem with my 2015 Z4 35i. At 25,000 miles, replaced rear tires; immediately afterwards, at highway speeds, the car seemed to dance in the lane. I thought it was catching grooves in the road - but it lasted too long. Not noticeable at low speeds. It was not fun to drive on the interstate; felt like it was darting around in the lane. The eye-opener came at a semi-circle off ramp and high speed. The phrase "tank-slapper" comes to mind. It was a road/speed that I had taken numerous times before, but the car was severely oscillating between under-steer and over-steer. Scary experience.
I tried Yalferd's advice on resetting the electric steering (below) and it completely worked. I see that this did not work for Neg89, but it may work for the next person. Turn on car and center steering Turn all the way to left stop and hold 2 seconds Turn all the way to right stop and hold 2 seconds Turn all the way left, then turn all the way right bring back to center |
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e89, e89 bmw z4, handling., issue, unstable |
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