Traction control kicking in when turning right

[Thecakeisalie]

Originally Posted by Flarpswitch

What happens when you turn off the traction and stability control? I would first look at the wheel speed sensors and/or associated wiring for defects. Have you or anyone else checked for diagnostic codes?

So with the traction and stability control turned off, the car still loses grip on its rear left when I make a right turn at low speed. Same exact thing.

About the wheel speed sensors, Subaru ran diagnostics on my car two weeks back and found that the two front sensors weren't working (no reading at all). So they have replaced them with two new sensors, which are working well now. Everything else looked fine system-wise, according to Subaru.

I'm guessing it's more likely a mechanical problem than electronics then?

Again, I appreciate everyone's input and thoughts!

[Flarpswitch]

Diagnosing something like this from a distance is a challenge. One thing that I notice with the Torsen LSD on the BRZ/86 is that it is pretty aggressive. It feels like it treats even the slightest difference in rotational speed as a loss of traction. If what I understand so far is this: only on right hand turns the problem occurs, left turns are OK. Rear drive train components appear to be sound. When you say the left rear wheel loses grip, you mean it spins up trying to burn rubber? Or, does do you feel any wheel hopping; that is the wheel is more in sync with the right wheel and it drags and hops. If you found an open space where you can drive in tight circles left and right, what do you experience? You can try this at faster speeds, but don't get into trouble. Getting both rear wheels in the air, you can try turning each wheel one at a time forward and reverse with the driveshaft locked. Feel for any differences in movement. Note the direction of wheel spin on the opposite side if any. Next, with the drive shaft free to turn, turn the wheels manually again. If the opposite wheel turns, have someone restrain it and note any movement in the drive shaft. Any limited slip differential will behave differently from an open differential. There are many types of LSD and the Torsen is just one of them. Differential failures are not the most common thing at low mileage. In my experience, the most common failure is a pinion bearing, often accompanying the failure of the rear drive shaft u-joint. One time I had a differential that lost a ring gear bolt that floated around in the housing. The first thing it did was get in the spider gears and mess with the differential action. After it did damage there and fell out into the case, everything seemed to be ok for about a week or so until at high speed on the highway, the bolt got swept up in the oil flow and wedged between the ring gear and the differential housing casting blowing a gaping hole in it. Sounded like a gun shot. Layers of plastic bags and tape got it back to the garage. I once loaned out a car and later discovered that it had taken a turn too tight and the right rear wheel hopped a curb. It was later that week at 2AM and 10 degrees F I was stopped at a light. When the light changed I let out the clutch and BANG! The engine raced as if I was in neutral. The short drive shaft had broken right at the spline where is goes into the carrier. It was an easy fix since it was independent rear suspension and I could replace the right shaft without having to remove the differential from the frame. That did not change the fact that I was royally pissed at my buddy. Don't loan your car out to a Hoon. Has this car seen some serious drifting?

My suspecting the differential is sort of grabbing at straws. My two BRZ cars are the only Torsen diffs that I have any experience with and I have never had one apart on the work bench. I have read up and watched videos a dozen times and I can't completely grasp why it works the way it does. It is one of those things that I would have to take apart to see. When the car is driving straight, equal amounts of torque are applied to each wheel. There is a threshold where the tire loses traction and it slips. There is a certain amount of torque bias that the differential will allow and then it starts locking (or not). If something is whacked internally, could left wheel or right wheel bias be different accounting for only right turns affected?

I have sympathy for the mechanics who can't figure this out. When I twisted wrenches for money, I always got the stuff no one else could figure out or knew before hand that they would loose their lunch money on the job. I would tell the boss to take me off flat rate hours for the job and pay me hourly. I have found stuff that came out of the factory that because you assume they did it 'right' you would not think to go down that road. Some highlights are clutch disks installed backwards at the factory, overhead camshafts installed with the valve timing retarded and a crankshaft that did not have oil passages drilled from the mains to the connecting rod journals. The crowning jewel was when I got into a shouting match with the factory man from Rolls Royce after I repaired the charging system and I told him that it was an easy fix pointing to an MG-B in the next stall: They are all the same, there is the front, there is the back, it has four wheels and a motor... what else is there to know? Well, the one mechanic who was certified was on 'Holiday' and I was the only one that was not scared shitless to touch the Rolls. I did borrow the car for the weekend for a quality control road test. Lovely automobile, so I can sort of understand why the factory guy got huffy. That does not change the fact that he was a butthole.

I just have to know what is up with this BRZ. Probably nothing I thought of.

[NoHaveMSG]

Check tire pressure, then have alignment checked. It was done a month ago, something not torqued properly could have slipped. I'd also check the speed sensors as mentioned, not too hard to knock one and damage it, they are just held in with a single 10mm.

I'd be surprised if a wheel bearing caused this. I have killed a number of them with no behaviour like this. Doesn't rule it out though.

[Ultramaroon]

Originally Posted by NoHaveMSG

Check tire pressure, then have alignment checked. It was done a month ago, something not torqued properly could have slipped. I'd also check the speed sensors as mentioned, not too hard to knock one and damage it, they are just held in with a single 10mm.

I'd be surprised if a wheel bearing caused this. I have killed a number of them with no behaviour like this. Doesn't rule it out though.

RZNT4R reminded me of how spoiled we are with with our non-corrosive winters. I grew up just across the lake from Toronto and, while we didn't have wheel speed sensors, I can easily picture the failures he describes.

[soundman98]

my money is still on either alignment or bushings. a right-hand-locking-diff could be a factory mechanical defect, but low likelihood

[Ultramaroon]

Originally Posted by soundman98

my money is still on either alignment or bushings. a right-hand-locking-diff could be a factory mechanical defect, but low likelihood

Mine is too, but I've come to see the wisdom of considering the sensor in the big picture.

[NoHaveMSG]

Originally Posted by Ultramaroon

Mine is too, but I've come to see the wisdom of considering the sensor in the big picture.

I forget we don't have to deal with the scourge of vehicles in the northern climates.

[Flarpswitch]

Originally Posted by Ultramaroon

RZNT4R reminded me of how spoiled we are with with our non-corrosive winters. I grew up just across the lake from Toronto and, while we didn't have wheel speed sensors, I can easily picture the failures he describes.

Ha ha ha ha. Memories. Seems like all of my old British cars had stuff falling off. A door falling off onto the sidewalk is no way to impress a girl on a first date. So many rust stories, but one that is classic: I was driving my Austin Mini westbound on I-80 in New Jersey when I noticed the dash lights blinking and the ammeter going nuts. Checking the mirrors and preparing to drive off to the shoulder, I saw in the rear view mirror a trail of liquid and black stuff. The battery box sits in the floor of the “Boot” and the bottom rusted out causing the battery to fall through and drag by the cables on the ground. The bottom of the battery wore down exposing the plates and draining the acid. Since the engine was easy to start by pushing the car and it had a generator, I drove home and stole a battery out of my Triumph so I could do my pizza delivery that night. Helps to have a buddy with a welding torch. Rust happens.

[Ultramaroon]

Originally Posted by Flarpswitch

Ha ha ha ha. Memories. Seems like all of my old British cars had stuff falling off. A door falling off onto the sidewalk is no way to impress a girl on a first date. So many rust stories, but one that is classic: I was driving my Austin Mini westbound on I-80 in New Jersey when I noticed the dash lights blinking and the ammeter going nuts. Checking the mirrors and preparing to drive off to the shoulder, I saw in the rear view mirror a trail of liquid and black stuff. The battery box sits in the floor of the “Boot” and the bottom rusted out causing the battery to fall through and drag by the cables on the ground. The bottom of the battery wore down exposing the plates and draining the acid. Since the engine was easy to start by pushing the car and it had a generator, I drove home and stole a battery out of my Triumph so I could do my pizza delivery that night. Helps to have a buddy with a welding torch. Rust happens.

I remember when my dad was bench-testing a generator, he showed me how it wouldn't work unless it was fed some initial current through the field coil. I learned the need for some battery even when bump starting. At least that's how it was on 6-Volt VWs.

[Flarpswitch]

Originally Posted by Ultramaroon

I remember when my dad was bench-testing a generator, he showed me how it wouldn't work unless it was fed some initial current through the field coil. I learned the need for some battery even when bump starting. At least that's how it was on 6-Volt VWs.

Correct, unless the generator is a magneto. I pulled the battery up through the floor, wrapped it in an old rubberized tarp. The battery despite its condition, still had enough power to light the idiot light, but not the starter. One person alone could push start a Mini and if nimble enough, jump in the car and not get run over. You can skate board the car with you right toe on the clutch or get the car rolling and jump in. Mine barely tipped 1,300 lbs. More than a couple of times I would find it parked on the sidewalk courtesy of a random football squad fueled by alcohol.

[Ultramaroon]

Originally Posted by Flarpswitch

The battery despite its condition, still had enough power to light the idiot light, but not the starter.

Ah, that helps me. I guess the cell will work as long as it's still wet. I've bump-started every car I've owned, including the frs, but I'm a pretty big guy. I only bumped the frs to prove to myself that I could do it.

[soundman98]

Originally Posted by Ultramaroon

Ah, that helps me. I guess the cell will work as long as it's still wet. I've bump-started every car I've owned, including the frs, but I'm a pretty big guy. I only bumped the frs to prove to myself that I could do it.

i should probably try to do this some time.. the push-start part feels different to me though...

[Ultramaroon]

Originally Posted by soundman98

i should probably try to do this some time.. the push-start part feels different to me though...

I don't remember if first gear was too short. It took me a couple whacks.

[Thecakeisalie]

Hi everyone, I have an update... My traction control issue has been solved!

A workshop managed to find that the bolts on my control arm (located at the front) were loose for some reason. After tightening them, no more traction control kicking in at low speed at all!

What a relief. It has been 6 months of going from one workshop to another, which always ended with "Sorry, we couldn't find what's wrong." Everyone kept focusing on the rear (because the car's rear would slide pretty badly at right turns, thus triggering the traction control), but all along the source of the problem was with the front.

I hope my experience will help others in a similar situation next time.