VDC Issues With Correct Tyres
05-30-2020, 06:50 PM
#1
VDC Issues With Correct Tyres
Hi all,
I'm having a few issues with VDC on my 2007 at the minute. When i punch the current tyres sizes into a comparison website, the diameters seem close enough to the stock size. Front is a 265/35/19, rear is a 285/35/19. I think that comes to 1.3% bigger at the front, and 0.6% bigger at the rear.
Whats happening is that VDC seems to be firing off quite often going through corners at rather moderate speeds, where I never used to hear a peep from it. Maybe a couple of times I'd heard the ABS motor fire up, but it would have been going as fast as I'd find comfortable on the road.
It's doing any variation from just the ABS motor firing off a little bit, all the way to quite a big lurch from the rear of the car where it seems to be putting quite a lot of braking into the rear wheels plus slip lights flashing, throttle feeling like it's being cut. Sometimes it almost feels like it's going to cause an accident with how randomly and suddenly it chucks the brakes on the rear. Other times it will just be coasting down a hill, slight corner and again, it will suddenly lurch and chuck some braking force on for reasons unknown to me.
The trouble is, I've always ran these same tyre sizes since I first got it. Through a set of Falken FK453's put on at the same time, then a Pirelli P-Zero Rosso replacement set on the rear. Then when the Falken fronts went, a Michelin Pilot 4S replacement. And now the Pirelli's are gone, a matching Michelin Pilot 4S rear.
It had really wonky sizes when I first drove it (huge fronts and tiny rears), and that had some obvious problems. Slip lights when accelerating in a straight line, etc. But since I ran these current sizes it's been fine.
The weird thing is that these issues started after I had the rears replaced in December 2019. So my thoughts obviously go to the tyre sizing being the cause. But again, a partially worn front set, and a new rear set...these should be about as bang on as I can get for VDC and plus sized tyres and wheels.
I've just had an alignment done incase something was wonky there, but no. Tiny bit of toe difference at the front, and we pulled a bit of camber off one rear (done for previous tyre rub issues).
Also had a look at the sensors and everything while on the hoist, not like anything was damaged, etc.
There's a couple of things in my mind, but I'm really not sure what would affect VDC.
First is different wheels. I had a new set of wheels put on, same Work wheels, same diameter, slightly narrower width and pulled in offset wise a little bit for guard clearance. Is there something in the track that could affect VDC? Or scrub radius or something?
The other is a tired VLSD, currently done 190,000kms. Would that have some kind of bearing on what VDC is expecting to see? I'm thinking of when it seems to fire off while coasting down a slope going around a curve.
I'm having a few issues with VDC on my 2007 at the minute. When i punch the current tyres sizes into a comparison website, the diameters seem close enough to the stock size. Front is a 265/35/19, rear is a 285/35/19. I think that comes to 1.3% bigger at the front, and 0.6% bigger at the rear.
Whats happening is that VDC seems to be firing off quite often going through corners at rather moderate speeds, where I never used to hear a peep from it. Maybe a couple of times I'd heard the ABS motor fire up, but it would have been going as fast as I'd find comfortable on the road.
It's doing any variation from just the ABS motor firing off a little bit, all the way to quite a big lurch from the rear of the car where it seems to be putting quite a lot of braking into the rear wheels plus slip lights flashing, throttle feeling like it's being cut. Sometimes it almost feels like it's going to cause an accident with how randomly and suddenly it chucks the brakes on the rear. Other times it will just be coasting down a hill, slight corner and again, it will suddenly lurch and chuck some braking force on for reasons unknown to me.
The trouble is, I've always ran these same tyre sizes since I first got it. Through a set of Falken FK453's put on at the same time, then a Pirelli P-Zero Rosso replacement set on the rear. Then when the Falken fronts went, a Michelin Pilot 4S replacement. And now the Pirelli's are gone, a matching Michelin Pilot 4S rear.
It had really wonky sizes when I first drove it (huge fronts and tiny rears), and that had some obvious problems. Slip lights when accelerating in a straight line, etc. But since I ran these current sizes it's been fine.
The weird thing is that these issues started after I had the rears replaced in December 2019. So my thoughts obviously go to the tyre sizing being the cause. But again, a partially worn front set, and a new rear set...these should be about as bang on as I can get for VDC and plus sized tyres and wheels.
I've just had an alignment done incase something was wonky there, but no. Tiny bit of toe difference at the front, and we pulled a bit of camber off one rear (done for previous tyre rub issues).
Also had a look at the sensors and everything while on the hoist, not like anything was damaged, etc.
There's a couple of things in my mind, but I'm really not sure what would affect VDC.
First is different wheels. I had a new set of wheels put on, same Work wheels, same diameter, slightly narrower width and pulled in offset wise a little bit for guard clearance. Is there something in the track that could affect VDC? Or scrub radius or something?
The other is a tired VLSD, currently done 190,000kms. Would that have some kind of bearing on what VDC is expecting to see? I'm thinking of when it seems to fire off while coasting down a slope going around a curve.
05-31-2020, 06:39 AM
#3
350Z/370Z Tech Moderator
MY350Z.COM
MY350Z.COM
Hi all,
I'm having a few issues with VDC on my 2007 at the minute. When i punch the current tyres sizes into a comparison website, the diameters seem close enough to the stock size. Front is a 265/35/19, rear is a 285/35/19. I think that comes to 1.3% bigger at the front, and 0.6% bigger at the rear.
Whats happening is that VDC seems to be firing off quite often going through corners at rather moderate speeds, where I never used to hear a peep from it. Maybe a couple of times I'd heard the ABS motor fire up, but it would have been going as fast as I'd find comfortable on the road.
It's doing any variation from just the ABS motor firing off a little bit, all the way to quite a big lurch from the rear of the car where it seems to be putting quite a lot of braking into the rear wheels plus slip lights flashing, throttle feeling like it's being cut. Sometimes it almost feels like it's going to cause an accident with how randomly and suddenly it chucks the brakes on the rear. Other times it will just be coasting down a hill, slight corner and again, it will suddenly lurch and chuck some braking force on for reasons unknown to me.
The trouble is, I've always ran these same tyre sizes since I first got it. Through a set of Falken FK453's put on at the same time, then a Pirelli P-Zero Rosso replacement set on the rear. Then when the Falken fronts went, a Michelin Pilot 4S replacement. And now the Pirelli's are gone, a matching Michelin Pilot 4S rear.
It had really wonky sizes when I first drove it (huge fronts and tiny rears), and that had some obvious problems. Slip lights when accelerating in a straight line, etc. But since I ran these current sizes it's been fine.
The weird thing is that these issues started after I had the rears replaced in December 2019. So my thoughts obviously go to the tyre sizing being the cause. But again, a partially worn front set, and a new rear set...these should be about as bang on as I can get for VDC and plus sized tyres and wheels.
I've just had an alignment done incase something was wonky there, but no. Tiny bit of toe difference at the front, and we pulled a bit of camber off one rear (done for previous tyre rub issues).
Also had a look at the sensors and everything while on the hoist, not like anything was damaged, etc.
There's a couple of things in my mind, but I'm really not sure what would affect VDC.
First is different wheels. I had a new set of wheels put on, same Work wheels, same diameter, slightly narrower width and pulled in offset wise a little bit for guard clearance. Is there something in the track that could affect VDC? Or scrub radius or something?
The other is a tired VLSD, currently done 190,000kms. Would that have some kind of bearing on what VDC is expecting to see? I'm thinking of when it seems to fire off while coasting down a slope going around a curve.
I'm having a few issues with VDC on my 2007 at the minute. When i punch the current tyres sizes into a comparison website, the diameters seem close enough to the stock size. Front is a 265/35/19, rear is a 285/35/19. I think that comes to 1.3% bigger at the front, and 0.6% bigger at the rear.
Whats happening is that VDC seems to be firing off quite often going through corners at rather moderate speeds, where I never used to hear a peep from it. Maybe a couple of times I'd heard the ABS motor fire up, but it would have been going as fast as I'd find comfortable on the road.
It's doing any variation from just the ABS motor firing off a little bit, all the way to quite a big lurch from the rear of the car where it seems to be putting quite a lot of braking into the rear wheels plus slip lights flashing, throttle feeling like it's being cut. Sometimes it almost feels like it's going to cause an accident with how randomly and suddenly it chucks the brakes on the rear. Other times it will just be coasting down a hill, slight corner and again, it will suddenly lurch and chuck some braking force on for reasons unknown to me.
The trouble is, I've always ran these same tyre sizes since I first got it. Through a set of Falken FK453's put on at the same time, then a Pirelli P-Zero Rosso replacement set on the rear. Then when the Falken fronts went, a Michelin Pilot 4S replacement. And now the Pirelli's are gone, a matching Michelin Pilot 4S rear.
It had really wonky sizes when I first drove it (huge fronts and tiny rears), and that had some obvious problems. Slip lights when accelerating in a straight line, etc. But since I ran these current sizes it's been fine.
The weird thing is that these issues started after I had the rears replaced in December 2019. So my thoughts obviously go to the tyre sizing being the cause. But again, a partially worn front set, and a new rear set...these should be about as bang on as I can get for VDC and plus sized tyres and wheels.
I've just had an alignment done incase something was wonky there, but no. Tiny bit of toe difference at the front, and we pulled a bit of camber off one rear (done for previous tyre rub issues).
Also had a look at the sensors and everything while on the hoist, not like anything was damaged, etc.
There's a couple of things in my mind, but I'm really not sure what would affect VDC.
First is different wheels. I had a new set of wheels put on, same Work wheels, same diameter, slightly narrower width and pulled in offset wise a little bit for guard clearance. Is there something in the track that could affect VDC? Or scrub radius or something?
The other is a tired VLSD, currently done 190,000kms. Would that have some kind of bearing on what VDC is expecting to see? I'm thinking of when it seems to fire off while coasting down a slope going around a curve.
Only kink in that analysis is that you had these sizes up until the problem started. The difference would be closer to 3% in the fronts-worn-rears-new scenario so that washes out the theory further. (Sounds like an AWD dilemma) Hmmmmm...
Well, something's got your wheel speed sensors in a state of distaste. I would see if maybe there's any local Z guys (club or something) that might have a pair of front wheels in stock diameters or closer to try out and see if the VDC-trigger problem persists.
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calvin.w (05-31-2020)
05-31-2020, 11:30 AM
#5
Yeah I'm aware of tyres being generally specced to those sizes. I've felt the falkens were the "smallest", with the pirelli and Michelin being bigger. But that makes it more confusing. It had worn falken fronts and new pirelli rears...and damn near bald pirelli rears and brand new Michelin fronts. And it drove fine, like the tolerance in vdc could handle it.
In a pretty small town here so I can try find some spare wheels to try run.
And I could try get some direct measurements of the tyres, see what their fitted diameters are.
Again though, like you said Micvelo, this should tend towards rears being too small, which should surely give false wheelspin readings. I had that when I first got it, with 255/40/19 front, and 275/30/19 rear. I would accelerate away from an intersection, and it would obviously see the rears going a lot faster than fronts, and slip would come on. Not had that in this currrent setup.
Is there diagnostic stuff a dealer can do? I'm picking they'll just see a modified car and leave it at that, fair enough I guess
In a pretty small town here so I can try find some spare wheels to try run.
And I could try get some direct measurements of the tyres, see what their fitted diameters are.
Again though, like you said Micvelo, this should tend towards rears being too small, which should surely give false wheelspin readings. I had that when I first got it, with 255/40/19 front, and 275/30/19 rear. I would accelerate away from an intersection, and it would obviously see the rears going a lot faster than fronts, and slip would come on. Not had that in this currrent setup.
Is there diagnostic stuff a dealer can do? I'm picking they'll just see a modified car and leave it at that, fair enough I guess
05-31-2020, 01:09 PM
#6
350Z/370Z Tech Moderator
MY350Z.COM
MY350Z.COM
Yeah, it’s weird that the VDC issue came on like that with the tires having been that size for a while already. BTW, have you tried pulling any codes? Possible their are stored faults That might shed some light on this.
Would still try to find a friendly z owner with spare fronts but barring that, you can try lowering front air pressure down to, say, 24lbs and inflate the rears to 44 and run the car conservatively, working up to speed to try and simulate size differential and seeing if the VDC triggers.
Don’t forget to re-set pressures after experimenting!
Would still try to find a friendly z owner with spare fronts but barring that, you can try lowering front air pressure down to, say, 24lbs and inflate the rears to 44 and run the car conservatively, working up to speed to try and simulate size differential and seeing if the VDC triggers.
Don’t forget to re-set pressures after experimenting!
Last edited by MicVelo; 05-31-2020 at 01:10 PM.
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calvin.w (05-31-2020)
05-31-2020, 02:50 PM
#7
Yeah, it’s weird that the VDC issue came on like that with the tires having been that size for a while already. BTW, have you tried pulling any codes? Possible their are stored faults That might shed some light on this.
Would still try to find a friendly z owner with spare fronts but barring that, you can try lowering front air pressure down to, say, 24lbs and inflate the rears to 44 and run the car conservatively, working up to speed to try and simulate size differential and seeing if the VDC triggers.
Don’t forget to re-set pressures after experimenting!
Would still try to find a friendly z owner with spare fronts but barring that, you can try lowering front air pressure down to, say, 24lbs and inflate the rears to 44 and run the car conservatively, working up to speed to try and simulate size differential and seeing if the VDC triggers.
Don’t forget to re-set pressures after experimenting!
Then again, maybe this is safe mode it's running in, can't follow a caravan slowly in the mountains without it firing off lol
Pressures would be a good idea too. Weird thing is I got the rears done in a town an hour and half a way. I didn't check the pressures, and trusted the techs, stupid me, but in the mountains coming home it was real taily. And yeah, that's when it started doing its thing. When I got home, I found they'd pumped everything up to 46psi. So I had thought that was the issue, and vdc was just working to control a car with way too much pressure in the tyres. But all I did from that point was commute, and then the virus lockdown. It's only now getting back onto the open roads I've found that nope, wasn't necessarily the pressures that caused it.
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06-07-2020, 03:54 PM
#8
Well I have some semi update to this. Found no massive differences in tyre diameters. I went for a long drive in the weekend, and it seems to only occur on right hand corners, and only on a neutral or off throttle input. If I powered through, didn't seem to do anything.
I can't remember hearing any noise from the abs pump going through left handers at all, no matter what I was doing.
What we found doing the alignment is a slightly weeping front left strut, and also the left side ball joint looks to have spat it's grease out.
What does the VDC system monitor and correct for? I'm wondering if it is somehow picking up understeer and trying to correct it?
I'm trying to think how it would pick that up though, steering input increasing with no change in car direction?
I can't remember hearing any noise from the abs pump going through left handers at all, no matter what I was doing.
What we found doing the alignment is a slightly weeping front left strut, and also the left side ball joint looks to have spat it's grease out.
What does the VDC system monitor and correct for? I'm wondering if it is somehow picking up understeer and trying to correct it?
I'm trying to think how it would pick that up though, steering input increasing with no change in car direction?
06-11-2020, 08:58 PM
#9
OK just checked codes and there are none, 0000 so not picking up any self diagnosis faults.
So then that would lead you to think it has to be something actually mechanical causing a handling problem, and VDC is trying to correct it, right?
So then that would lead you to think it has to be something actually mechanical causing a handling problem, and VDC is trying to correct it, right?
06-12-2020, 11:21 AM
#10
General & Tech Moderator
MY350Z.COM
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Ck to make sure all wheel speed sensors are mounted correctly.
06-12-2020, 09:38 PM
#11
Yeah I'd checked that a while back on a mates hoist, and again doing the alignment. Nothing stood out as wrong or damaged. Harnesses all intact and clipped up where they should be.
Does anyone know all the "things" that vdc monitors? Like what bits could be giving funky inputs to it.
Does it sense steering angle?
Does anyone know all the "things" that vdc monitors? Like what bits could be giving funky inputs to it.
Does it sense steering angle?
06-12-2020, 10:15 PM
#12
350Z/370Z Tech Moderator
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Yeah I'd checked that a while back on a mates hoist, and again doing the alignment. Nothing stood out as wrong or damaged. Harnesses all intact and clipped up where they should be.
Does anyone know all the "things" that vdc monitors? Like what bits could be giving funky inputs to it.
Does it sense steering angle?
Does anyone know all the "things" that vdc monitors? Like what bits could be giving funky inputs to it.
Does it sense steering angle?
Wheel speed - if spin is detected, brake at the spin wheel is applied and/or engine speed throttled back until wheel speeds are back within standard operational parameters.
Yaw - a gyroscopic reading of the body attitude in comparison with...
Steering Angle
Combination of all three areas determines what the ECU commands the car to do in order to regain control. Any fault in any of the monitoring components can trigger VDC.
06-12-2020, 10:39 PM
#13
VDC monitors three things - independently AND in tandem with each other -
Wheel speed - if spin is detected, brake at the spin wheel is applied and/or engine speed throttled back until wheel speeds are back within standard operational parameters.
Yaw - a gyroscopic reading of the body attitude in comparison with...
Steering Angle
Combination of all three areas determines what the ECU commands the car to do in order to regain control. Any fault in any of the monitoring components can trigger VDC.
Wheel speed - if spin is detected, brake at the spin wheel is applied and/or engine speed throttled back until wheel speeds are back within standard operational parameters.
Yaw - a gyroscopic reading of the body attitude in comparison with...
Steering Angle
Combination of all three areas determines what the ECU commands the car to do in order to regain control. Any fault in any of the monitoring components can trigger VDC.
I'd assume steering angle would be up in the upper column or something.
G sensor, no clue
Edit: Steering angle sensor will be the next thing to investigate. And seeing that can be reset at a dealer. Or whether it is actually stuffed. But all the threads I've seen just now state having warning lights showing when it's failed
Last edited by MB037; 06-12-2020 at 10:46 PM.
06-17-2020, 03:48 PM
#14
Ok so I drove around with a Nissan tech and the consult setup plugged in. Only fault code logged was a battery low voltage, that was around the lockdown time here. And unrelated to this issue.
Wheelspeed sensors were giving bang on the same speed readings. Absolute fractionally out at over 100kph, as in like flickering 1kph faster than the fronts. Did some hard weaving and cornering and it didn't give any erroneous readings, if a sensor was faulty or something interfering with its pickup. So that confirms the tyres are as good as I'll get for sizing I think.
Sadly the tech failed to check the steering angle sensor readout before it was recalibrated, but we did that a couple of times to make sure.
He also did the inertial unit or G sensor recalibration on a flat bit of concrete. Again, we couldn't find any faults or funny stuff being thrown by the system. He did say he had worked on another car with faults in it's VDC system, but that it would be logging faults when it was seeing inconsistent data, throwing up warning lights, etc. So he said the system should know when it isn't able to rely on any of its sensors or something doesn't line up with all the other sensors.
We sadly didn't have time to get out onto the main highway and hit some corners where it was triggering the VDC problems, and I was running up a rather reasonable bill for it all.
But I took it for a drive afterwards and sadly it was still doing the same thing as before.
So a little bit baffled now. I have a Drexler diff I need to fit, so if in any weird way something is playing up with the VLSD and causing it some grief, that should sort that. But other than the shock leaking which is probably not causing this, I'm really stumped now. Either way, I will be getting those two things sorted when possible.
Is wheel track front to rear somehow possible as a cause? Some wheels being further out and giving greater speed differentials when cornering?
The rears are set in a bit more compared to the fronts, I will be getting them spaced out a tiny tiny bit at some point. I highly doubt it as again it seemed quite alright when the Pirelli's were on the rear.
Wheelspeed sensors were giving bang on the same speed readings. Absolute fractionally out at over 100kph, as in like flickering 1kph faster than the fronts. Did some hard weaving and cornering and it didn't give any erroneous readings, if a sensor was faulty or something interfering with its pickup. So that confirms the tyres are as good as I'll get for sizing I think.
Sadly the tech failed to check the steering angle sensor readout before it was recalibrated, but we did that a couple of times to make sure.
He also did the inertial unit or G sensor recalibration on a flat bit of concrete. Again, we couldn't find any faults or funny stuff being thrown by the system. He did say he had worked on another car with faults in it's VDC system, but that it would be logging faults when it was seeing inconsistent data, throwing up warning lights, etc. So he said the system should know when it isn't able to rely on any of its sensors or something doesn't line up with all the other sensors.
We sadly didn't have time to get out onto the main highway and hit some corners where it was triggering the VDC problems, and I was running up a rather reasonable bill for it all.
But I took it for a drive afterwards and sadly it was still doing the same thing as before.
So a little bit baffled now. I have a Drexler diff I need to fit, so if in any weird way something is playing up with the VLSD and causing it some grief, that should sort that. But other than the shock leaking which is probably not causing this, I'm really stumped now. Either way, I will be getting those two things sorted when possible.
Is wheel track front to rear somehow possible as a cause? Some wheels being further out and giving greater speed differentials when cornering?
The rears are set in a bit more compared to the fronts, I will be getting them spaced out a tiny tiny bit at some point. I highly doubt it as again it seemed quite alright when the Pirelli's were on the rear.
06-17-2020, 05:28 PM
#15
New Member
As far as the wheel location in the wells, the rears do seem to be hiding inward more than the front. I think this is just what it looks like as the rear of the body is pretty thicc.
as far as everything else, no clue.
I was on a thread a while back and this guy couldn't figure out what was wrong with his Z. I think it was the ecm not sending "the go ahead" to the spark plugs for them to ignite. His Z ending up dying mid drive. I stayed with him through the entire thing giving him guesses based on my basic knowledge of the engine. Last guess was timing, it ended up being just that!
I tell you this because if you'd like, I could stick through this whole ordeal with you and give you my best guesses. Even research stuff
as far as everything else, no clue.
I was on a thread a while back and this guy couldn't figure out what was wrong with his Z. I think it was the ecm not sending "the go ahead" to the spark plugs for them to ignite. His Z ending up dying mid drive. I stayed with him through the entire thing giving him guesses based on my basic knowledge of the engine. Last guess was timing, it ended up being just that!
I tell you this because if you'd like, I could stick through this whole ordeal with you and give you my best guesses. Even research stuff
06-17-2020, 06:09 PM
#16
As far as the wheel location in the wells, the rears do seem to be hiding inward more than the front. I think this is just what it looks like as the rear of the body is pretty thicc.
as far as everything else, no clue.
I was on a thread a while back and this guy couldn't figure out what was wrong with his Z. I think it was the ecm not sending "the go ahead" to the spark plugs for them to ignite. His Z ending up dying mid drive. I stayed with him through the entire thing giving him guesses based on my basic knowledge of the engine. Last guess was timing, it ended up being just that!
I tell you this because if you'd like, I could stick through this whole ordeal with you and give you my best guesses. Even research stuff
as far as everything else, no clue.
I was on a thread a while back and this guy couldn't figure out what was wrong with his Z. I think it was the ecm not sending "the go ahead" to the spark plugs for them to ignite. His Z ending up dying mid drive. I stayed with him through the entire thing giving him guesses based on my basic knowledge of the engine. Last guess was timing, it ended up being just that!
I tell you this because if you'd like, I could stick through this whole ordeal with you and give you my best guesses. Even research stuff
But you're right in the stock car looking a bit like that. I'm sure it's something to do with giving a neutral or understeering handling to the car. Or like most road cars.
Yeah this is a slightly weird one, it surely can't be the tyres giving some shonky handling, I'd pick the Michelin Pilot 4S over the Falkens I put on it.
And the only things I'm seeing "wrong" so far is the shock leaking and the diff possibly being past it.
If all else fails and there's no other ideas, I may pay another wad and get the Nissan tech back in with the laptop and go find some corners and get it to trigger off while he looks at the numbers.
06-18-2020, 04:56 AM
#17
General & Tech Moderator
MY350Z.COM
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Something we haven't discussed -
Are you running oem steering wheel or has it ever been taken off? Steering wheel angle is a function of VDC as mentioned above. The G/Yaw sensor is a white box mounted rearward of shifter but in 8 years here I've never heard of one going bad.
Are you running oem steering wheel or has it ever been taken off? Steering wheel angle is a function of VDC as mentioned above. The G/Yaw sensor is a white box mounted rearward of shifter but in 8 years here I've never heard of one going bad.
06-18-2020, 09:07 AM
#18
Something we haven't discussed -
Are you running oem steering wheel or has it ever been taken off? Steering wheel angle is a function of VDC as mentioned above. The G/Yaw sensor is a white box mounted rearward of shifter but in 8 years here I've never heard of one going bad.
Are you running oem steering wheel or has it ever been taken off? Steering wheel angle is a function of VDC as mentioned above. The G/Yaw sensor is a white box mounted rearward of shifter but in 8 years here I've never heard of one going bad.