Losing grip or DSC fault?

[s512]

Hello all!

Since having new rear tyres fitted, I've had an issue with traction... going round some bends around > 40mph (definitely not asking too much), the traction control kicks in and jabs the brakes. Before having the rear tyres fitted I'd rarely been acquainted with the traction control (only in the wet...) and never had it brake the front wheels. I guess this would mean the front wheels are losing grip? Or could it be rear too? Or just a fault with the DSC?

Disable the DSC and it goes round the corner without problems as far as I can tell...

New front tyres fitted June 2015 and they still look good to me. The rear tyres were fitted Feb 2016. All Michelin pilot sports.

I also had a Bilstein B12 kit fitted June 2015 (slightly lowered damper & spring set), and since then had no problems with grip at all. It's only been since the new rear tyres... anyone have any ideas?

It's a 2000 3.0.

Many thanks,
Sam

 

[littlefeller]

check the rolling rad of the rears, if they are bigger than the front then going round bends could turn the outer rear to the point the ecu sees the difference compared to the fronts as wheel slip.

 

[littlefeller]

there are a couple of things you can check here, tyre pressure being the first, is your steering wheel central?

 

[s512]

check the rolling rad of the rears, if they are bigger than the front then going round bends could turn the outer rear to the point the ecu sees the difference compared to the fronts as wheel slip.

As far as I know, they're the same tyre sizes that were on there before... but I'll see if I can fish out some old photos to check. Pretty sure they are wider that the fronts, but that's the same for all Z3's I believe?

there are a couple of things you can check here, tyre pressure being the first, is your steering wheel central?

I've had wheel alignment checked and no issues there. Wheel is central. Haven't checked pressures recently, but have done since they were fitted and are not flat. Could be over inflated slightly... it is quite common for garages to over-inflate tyres...

Thanks.

 

[littlefeller]

over inflation would be my first port of call.
i recently had asc issues immediately after new tires, i assumed it was the tires. turned out to be just a coincidence, my asc was knackered.
are you getting any warning lamps on?

 

[s512]

over inflation would be my first port of call.
i recently had asc issues immediately after new tires, i assumed it was the tires. turned out to be just a coincidence, my asc was knackered.
are you getting any warning lamps on?

Nope, only the traction lamp flashing up when it kicks in. I'll check the pressures this evening and let you know.. hopefully it's something this simple!

 

[Brian H]

Couple of questions: -

• Is your steering wheel bang in the center when driving straight?
• Can you confirm Tyre sizes pls?

Cheers

Brian

 

[s512]

Couple of questions: -

• Is your steering wheel bang in the center when driving straight?
• Can you confirm Tyre sizes pls?

Cheers

Brian

Fronts: 225/45 ZR17
Rears: 245/40 ZR17

Just went out for a quick spin - the steering wheel is very slightly turned to the right when driving straight, but definitely not by much...

Thanks,
Sam

 

[Brian H]

Fronts: 225/45 ZR17
Rears: 245/40 ZR17

Just went out for a quick spin - the steering wheel is very slightly turned to the right when driving straight, but definitely not by much...

Thanks,
Sam

OK Sam, next question, does the DSC trigger more one way than the other? The DSC system is a complex system which looks at the wheels speeds, steering angle sensor and the yaw sensor, if you are driving down the road with a crooked wheel when you turn in the direction that the wheel is pointing the car cannot make sense of all the sensor inputs and therefore it will throw up DSC error.

 

[s512]

OK Sam, next question, does the DSC trigger more one way than the other? The DSC system is a complex system which looks at the wheels speeds, steering angle sensor and the yaw sensor, if you are driving down the road with a crooked wheel when you turn in the direction that the wheel is pointing the car cannot make sense of all the sensor inputs and therefore it will throw up DSC error.

There's one bend on my commute where it always happens (provided I'm going fast enough). On this particular bend, the DSC kicks in more often when coming home/turning left - but of course that could be related to wanting to get home faster! It doesn't happen as much going to work/turning right... tomorrow I can try taking the corner at the same speed both ways to see what happens...

To add to the confusion, this corner is slightly banked so the road dips on the inside (turning left/coming home). The DSC kicks in on other flatter roads too, though.

Seems weird that the issue just came about after having the rear tyres fitted, unless it's just an unfortunate coincidence...

Cheers

 

[Dino D]

I've had strange handling when the tyres where fitted 'inside out' i.e. they have a side that needs to on the outside of the rim.
Also worth checking they fitted with the rotation arrow pointing the right way (if they have arrows).

 

[the Nefyn cat]

Had the same thing on mine after having new rear tyres fitted. Back to normal after new front tyres, guess the electronics are just a bit too sensitive and reading the extra few mm as meaning the wheels are rotating at different enough speeds to be on the way to flying through a hedge backwards. Maybe.

 

[Brian H]

There's one bend on my commute where it always happens (provided I'm going fast enough). On this particular bend, the DSC kicks in more often when coming home/turning left - but of course that could be related to wanting to get home faster! It doesn't happen as much going to work/turning right... tomorrow I can try taking the corner at the same speed both ways to see what happens...

To add to the confusion, this corner is slightly banked so the road dips on the inside (turning left/coming home). The DSC kicks in on other flatter roads too, though.

Seems weird that the issue just came about after having the rear tyres fitted, unless it's just an unfortunate coincidence...

Cheers

Probably not a coincidence but with the steering wheel slightly misaligned and the new rear tyres you are just going over the acceptable tolerance within the DSC system. You also have to remember our cars are getting on now and things like the rear beam bushes are now alot weaker than they were so you will get more body roll. all these little things add up.

 

[Antm72]

Does the zed store adaptions in the modules ? I know you can clear the ecu of these and get it to learn again. Is it sensing a difference between what it new and how it is or just with in tolerences ?

 

[s512]

I've had strange handling when the tyres where fitted 'inside out' i.e. they have a side that needs to on the outside of the rim.
Also worth checking they fitted with the rotation arrow pointing the right way (if they have arrows).

Seems to be all fitted correctly...

@the Nefyn cat & @Brian H - Yeah, I guess you're right, that could make sense...

As @Antm72 suggests, maybe there is a way of resetting the system somehow?

 

[motco]

The DSC system is remarkably sophisticated and very effective. Anything that gets in its way really should be remedied. An experience with mine earlier this year may interest you.

I was travelling clockwise on M25 near Reigate on New Year's Day at mid to late afternoon in my Z3 2.2 Sport. It was getting dark and the traffic was moderate (light by M25 standards) with very few lorries but lots of cars. I was on cruise at a GPS 70 mph in lane 3 of 4. On my right and to the rear was a large white car (Audi I think) gaining on me by about five to ten mph, and on my left in lane two another car (unknown make) travelling some five to ten mph slower than I was. So far, so normal on M25 with all its gantry cameras causing little speed differential across the outermost three lanes. There was nothing ahead of the lane two car for some distance and indeed not a lot immediately ahead of me because the braking distance at that speed dictates a good headway to the car ahead. As I drew alongside the car to my left he suddenly and unnecessarily started to change lane towards my nearside. This was no lane drift; this was a deliberate lane-change manoeuvre and had I not taken evasive action he would have barged me across to lane four where the Audi was now approaching my rear quarter. Instinctively I swung the wheel quickly through about 90 degrees right and then instantly back sufficiently to regain the course in the lane in order to move the car at least half a vehicle's width towards, but not into the path of the car in lane four. He (the Audi) must have lost control of his bowels when he saw what was apparently a small two-seater diving across his path and then, equally suddenly stopping the swerve! Doing this in some (most) cars on a damp concrete road surface at 70mph would almost certainly have resulted in a total loss of directional control, but in the Z, thanks to DSC, it did exactly what was asked of it with no more than a couple of flashes of the yellow DSC light on the dash! I am so glad I took the Z yesterday and not my Jag X Type - that has traction control and ABS but no stability control. What's more it's a bit of a heavy lump and would have been unlikely to be as nimble as the Z anyway.

Over the years I have driven in excess of a million miles and can honestly say that I have never had such a stupid driver threaten my safety.

 

[s512]

The DSC system is remarkably sophisticated and very effective. Anything that gets in its way really should be remedied. An experience with mine earlier this year may interest you.

I was travelling clockwise on M25 near Reigate on New Year's Day at mid to late afternoon in my Z3 2.2 Sport. It was getting dark and the traffic was moderate (light by M25 standards) with very few lorries but lots of cars. I was on cruise at a GPS 70 mph in lane 3 of 4. On my right and to the rear was a large white car (Audi I think) gaining on me by about five to ten mph, and on my left in lane two another car (unknown make) travelling some five to ten mph slower than I was. So far, so normal on M25 with all its gantry cameras causing little speed differential across the outermost three lanes. There was nothing ahead of the lane two car for some distance and indeed not a lot immediately ahead of me because the braking distance at that speed dictates a good headway to the car ahead. As I drew alongside the car to my left he suddenly and unnecessarily started to change lane towards my nearside. This was no lane drift; this was a deliberate lane-change manoeuvre and had I not taken evasive action he would have barged me across to lane four where the Audi was now approaching my rear quarter. Instinctively I swung the wheel quickly through about 90 degrees right and then instantly back sufficiently to regain the course in the lane in order to move the car at least half a vehicle's width towards, but not into the path of the car in lane four. He (the Audi) must have lost control of his bowels when he saw what was apparently a small two-seater diving across his path and then, equally suddenly stopping the swerve! Doing this in some (most) cars on a damp concrete road surface at 70mph would almost certainly have resulted in a total loss of directional control, but in the Z, thanks to DSC, it did exactly what was asked of it with no more than a couple of flashes of the yellow DSC light on the dash! I am so glad I took the Z yesterday and not my Jag X Type - that has traction control and ABS but no stability control. What's more it's a bit of a heavy lump and would have been unlikely to be as nimble as the Z anyway.

Over the years I have driven in excess of a million miles and can honestly say that I have never had such a stupid driver threaten my safety.

Wow, very impressive stuff from the Z. Glad you made it out of there safe!

I've read forums mentioning re-calibrating the steering angle sensor... but I will get it more aligned with the wheels to start with. Thanks all.

 

[the Nefyn cat]

The DSC system is remarkably sophisticated and very effective. Anything that gets in its way really should be remedied. An experience with mine earlier this year may interest you.

I was travelling clockwise on M25 near Reigate on New Year's Day at mid to late afternoon in my Z3 2.2 Sport. It was getting dark and the traffic was moderate (light by M25 standards) with very few lorries but lots of cars. I was on cruise at a GPS 70 mph in lane 3 of 4. On my right and to the rear was a large white car (Audi I think) gaining on me by about five to ten mph, and on my left in lane two another car (unknown make) travelling some five to ten mph slower than I was. So far, so normal on M25 with all its gantry cameras causing little speed differential across the outermost three lanes. There was nothing ahead of the lane two car for some distance and indeed not a lot immediately ahead of me because the braking distance at that speed dictates a good headway to the car ahead. As I drew alongside the car to my left he suddenly and unnecessarily started to change lane towards my nearside. This was no lane drift; this was a deliberate lane-change manoeuvre and had I not taken evasive action he would have barged me across to lane four where the Audi was now approaching my rear quarter. Instinctively I swung the wheel quickly through about 90 degrees right and then instantly back sufficiently to regain the course in the lane in order to move the car at least half a vehicle's width towards, but not into the path of the car in lane four. He (the Audi) must have lost control of his bowels when he saw what was apparently a small two-seater diving across his path and then, equally suddenly stopping the swerve! Doing this in some (most) cars on a damp concrete road surface at 70mph would almost certainly have resulted in a total loss of directional control, but in the Z, thanks to DSC, it did exactly what was asked of it with no more than a couple of flashes of the yellow DSC light on the dash! I am so glad I took the Z yesterday and not my Jag X Type - that has traction control and ABS but no stability control. What's more it's a bit of a heavy lump and would have been unlikely to be as nimble as the Z anyway.

Over the years I have driven in excess of a million miles and can honestly say that I have never had such a stupid driver threaten my safety.

Very lucky there. Mind you, try driving around in a lorry with a bunch of horses on board and you'll soon find that there's a lot of blind/stupid/inconsiderate people out there. Damn driving test is too easy (mutter grumble).

 

[motco]

Very lucky there. Mind you, try driving around in a lorry with a bunch of horses on board and you'll soon find that there's a lot of blind/stupid/inconsiderate people out there. Damn driving test is too easy (mutter grumble).

Now that's what you call a 'live load'!

 

[s512]

Just an update: all 4 tyres were over-inflated so let some air out.... unfortunately the problem still exists (although possibly to a lesser extent).

Next step to get steering wheel lined up....