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Vorsprung_CJB Vorsprung_CJB is offline
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Default Issue with DSC, brakes, or alignment? - 06-25-2017, 10:25 AM

Was hoping to pick your brains about a minor issue I am having.

Recently had rear tires installed and an alignment at a tire shop. Alignment was bad so I took it to my BMW indy shop to get a pro alignment, and also new rear brakes (pads/rotors) and also had 4 wheels refurbed, among other maintenance items.

Even after the pro alignment, the car feels unstable, especially at higher speeds. Pressures are all correct, and the rears should be more than broken in by now. Braking is fine with new rears.

But here is the additional weirdness. At higher speeds (50-60+) there are times, especially when on a long sweeping turn and decelerating, where it feels like individual brakes are coming on, but no DSC light comes on. Makes the car slightly unsettled/pull. On a few rare occasions it did trigger a full DTC flash, usually when turning+braking or changing lanes on a curve. Happens even with 1 push and full off of DTC. Also seems to slightly trigger when accelerating (normally, not hard) while on a slight curve.

I'm thinking maybe something with the e-Diff, or maybe DSC? Maybe a wheel speed sensor got bumped? Steering sensor? Maybe a front tire issue? I trust their alignment but maybe it needs a tweak. No codes or errors. Will be taking it back next week, but what do you all think?

Thanks
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Default 06-25-2017, 10:47 AM

Are you sure your alignment set correctly ? Worth to run it on another alignment to make sure it's not off alignment and all set correctly as per the correct chassis and model and year

Had a friend done alignment and car felt weird, the guy selected different model and wheel base and rim size!! Once loaded on different alignment it was way off alignment


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Default 06-25-2017, 03:49 PM

It is possible I suppose, but the shop is run by a couple of BMW master techs and I specifically told them I was trying to fix what I thought was a bad alignment, so I doubt they would make a mistake. I did forget to get a printout though.

I got my INPA working and it seemed like all the wheel speed sensors were in sync. Steering and yaw were very slightly off but well within the green area. No DSC events logged other than from when the rear pads got low.

Guess I'll follow up with the shop later this week and see what they can think of.
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Default 07-05-2017, 03:29 PM

Just a followup if anyone was interested: They didn't find any glaring problem but re-do the alignment from scratch, and it seems to be 85% better. More stable on the highway for sure. Still feels like something isn't quite right, slightly unsettled.

More concerning is that the DSC still seems to be flaky. On rare occasions, when turning and braking, especially at high speeds, it seems like it freaks out and all 4 wheels want to do something different. Very scary when I'm on a back road going quickly, brake on a slight curve, and the car starts fighting me.

Still no DSC errors/codes though. I wonder if the fact the rear brakes are new is an issue, as maybe I am getting rear bias since they are better? Or if there is some calibration issue with the steering angle, yaw sensors or something else?

Any other ideas before I get into more troubleshooting?

EDIT: Got my INPA working, do these look within range?
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Last edited by Vorsprung_CJB; 07-05-2017 at 04:01 PM..
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