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So I'm having this issue where VDC kicks in and the slip light flashes sometimes in relatively slow right turns. It happens at speeds in between say 25 and 50 mph. Any slower or faster than that and its all good.
With VDC turned off it behaves perfectly, no oversteer or understeer at those speeds.
It only happens when turning right, not when turning left.
I had a professional alignment done with a Hunter unit about 2 weeks ago and the spec sheets all came out within spec although we left a little more camber in it to give the tires some more room under compression. The rear camber was set to -2.03 degrees, fronts somewhere around that too but I didn't take a picture of it, still in the green though.
We set a slight toe in (within spec) in the rear for stability.
It has a little more aggressive turn in than stock and feels a bit loose under hard braking.
Anybody have an idea of what I could look at? Do ya'll think I need another alignment or can I adjust something else?
Here's the info on the car:
'08 350Z GT spec
Lowered a bit on Bilstein B16 coilovers (set to 3/10 front 2/10 rear)
Hotchkis adjustable front and rear sway bars, softest setting in the rear, mid setting in the front
Whiteline adjustable drop links
SPL V3 billet front uppers
SPL V3 billet rear camber arms
SPL V3 billet rear traction arms
Tires are Vredestein Ultrac Vortis 255/35/19 fronts and brand new 275/35/19 rears
Tyre pressures set to 40.5 psi cold all around.
Have you done a scan of the diagnostic system to find any VDC error codes held in memory? You'll need a code scanner that can check the BCM and ABS systems as well as ECM codes.
Also, a cold tire inflation of 40.5 PSI sounds higher than any other tire I've heard of. Overinflation could cause the center of your tires to bow out and change the contact patch.
@dkmura
I haven't scanned it, I'll try that tomorrow and see if anything comes up. I scanned it a week ago while changing spark plugs because I forgot to connect one of the coil packs and was too lazy to look in the engine bay for which one it was but got nothing other than the cyl 5 misfire I was expecting.
Yeah the psi is quite high. The Vredesteins are suuuper grippy but have a pretty soft sidewall which makes them quiet and comfy while performing really well. In fast corners they can feel like they have some side to side flex in the sidewall which is why I run them with such a high psi. I've been using these tires for 3 years with about the same psi in em but I suppose they could be different from year to year so I'll try lowering the psi a bit tomorrow and see if there's any difference.
I'm also going to look at the front sway bar and see if there is any wierd pre load or anything since I had the car aligned and readjusted the rear sway bar.
Thanks for the reply, if anything else comes to mind please drop a comment, I'm always willing to learn more about my car.
So I'm having this issue where VDC kicks in and the slip light flashes sometimes in relatively slow right turns. It happens at speeds in between say 25 and 50 mph. Any slower or faster than that and its all good.
With VDC turned off it behaves perfectly, no oversteer or understeer at those speeds.
It only happens when turning right, not when turning left.
I had a professional alignment done with a Hunter unit about 2 weeks ago and the spec sheets all came out within spec although we left a little more camber in it to give the tires some more room under compression. The rear camber was set to -2.03 degrees, fronts somewhere around that too but I didn't take a picture of it, still in the green though.
We set a slight toe in (within spec) in the rear for stability.
It has a little more aggressive turn in than stock and feels a bit loose under hard braking.
Anybody have an idea of what I could look at? Do ya'll think I need another alignment or can I adjust something else?
Here's the info on the car:
'08 350Z GT spec
Lowered a bit on Bilstein B16 coilovers (set to 3/10 front 2/10 rear)
Hotchkis adjustable front and rear sway bars, softest setting in the rear, mid setting in the front
Whiteline adjustable drop links
SPL V3 billet front uppers
SPL V3 billet rear camber arms
SPL V3 billet rear traction arms
Tires are Vredestein Ultrac Vortis 255/35/19 fronts and brand new 275/35/19 rears
Tyre pressures set to 40.5 psi cold all around.
As mentioned above, tire pressures are a tad bit high cold. I'd try 35 to start.
You state that your rear tires are new; are your fronts worn? New tires are slippery and need to be driven a few hundred miles to remove the mold release agent (https://www.tirerack.com/tires/tiret....jsp?techid=5&). I learned my lesson after throwing on some 200TW and gunning it on a sweeper, VDC kicked in and kicked my brakes in to save me.
Your tires are within the 3% diameter difference that would kick VDC on (you're at 2.2%) so you are good there.
Its odd that you notice VDC kicking in only on right turns at slower speeds. I'd be interested to hear what others have to say.
If you hook up an advanced scanner, check the indicated steering angle with the wheel pointed straight ahead. I'm gonna guess it's not at zero. someone probably removed the steering wheel and put it back on off a tooth. They then corrected the steering by adjusting the toe. This will result in a steering wheel that's straight, but a steering angle sensor that's not. This can trigger the VDC.
The front tires have plenty of tread left. I only changed the rears because I wore them out from a poor alignment after I lowered the car and eh.. you know, some burnies hehe!
Thats also why I had an alignment done.
You're also correct, the steering wheel has been taken off, by me, 2 years ago and was replaced by a VQVortex half carbon unit. Its basically a reupholstered oem wheel and I made triple sure I put it back on straight, marked and counted the teeth and all myself. Its easy enough to pop the airbag off and double check though so I'll do that.
The steering angle was also measured and corrected in the Hunter alignment machine when I had the alignment done.
My first step will be to lower the tyre pressures to about 35, scan the car for codes and as I mentioned before check the sway bar situation just in case. Keep the ideas and suggestions coming though, I'm going to keep everything you guys come up with in mind.
Oh and sorry for replying late or at wierd times, I live in Sweden and have a 6-9 hour shift in time zone from most of you!
If you hook up an advanced scanner, check the indicated steering angle with the wheel pointed straight ahead. I'm gonna guess it's not at zero. someone probably removed the steering wheel and put it back on off a tooth. They then corrected the steering by adjusting the toe. This will result in a steering wheel that's straight, but a steering angle sensor that's not. This can trigger the VDC.
This is interesting, what would be a way to fix this? realign the steering wheel and realign the car? or is there a way to reset the steering angle sensor
This is interesting, what would be a way to fix this? realign the steering wheel and realign the car? or is there a way to reset the steering angle sensor
Yes the sensor can be re-learned. You'll need an advanced scanner, like a Snap-On Modis or Verus, or a Nissan Consult III. If you can't access one of those, a mid-level scanner with data display may at least show you what the sensor is reading. You can then turn the wheel until the sensor reads zero and then remove and re-clock the steering wheel to 12 o'clock.
I'm gonna guess your sensor is reading negative a few degrees when going straight. When you turn right a little, the sensor is reading zero so the car thinks you're going straight. Because you're turning, your outside wheels are spinning slightly faster than the insides. The car thinks you're going straight, but sees different speeds at the wheel speed sensors and figures you're sliding, so VDC kick on.
Yes the sensor can be re-learned. You'll need an advanced scanner, like a Snap-On Modis or Verus, or a Nissan Consult III. If you can't access one of those, a mid-level scanner with data display may at least show you what the sensor is reading. You can then turn the wheel until the sensor reads zero and then remove and re-clock the steering wheel to 12 o'clock.
I'm gonna guess your sensor is reading negative a few degrees when going straight. When you turn right a little, the sensor is reading zero so the car thinks you're going straight. Because you're turning, your outside wheels are spinning slightly faster than the insides. The car thinks you're going straight, but sees different speeds at the wheel speed sensors and figures you're sliding, so VDC kick on.
See this is why I come here and ask these questions, I had never ever thought of that myself.
That would make sense why it only triggers when turning one way.
I'll get on it tonight, been too busy with yard work for now.
Yes the sensor can be re-learned. You'll need an advanced scanner, like a Snap-On Modis or Verus, or a Nissan Consult III. If you can't access one of those, a mid-level scanner with data display may at least show you what the sensor is reading. You can then turn the wheel until the sensor reads zero and then remove and re-clock the steering wheel to 12 o'clock.
I'm gonna guess your sensor is reading negative a few degrees when going straight. When you turn right a little, the sensor is reading zero so the car thinks you're going straight. Because you're turning, your outside wheels are spinning slightly faster than the insides. The car thinks you're going straight, but sees different speeds at the wheel speed sensors and figures you're sliding, so VDC kick on.
I am learnt today. Looked up those advanced scanners and they ain't cheap.
Lowered tyre pressures to 35 psi cold, scanned the car for codes and ran a sensor diagnostic test. No codes and all sensors (that my scanner can read) reported back ok. I'm not sure my scanner can read data off the steering angle sensor though, probably not so that is still a possibility.
Went for a test drive and could NOT replicate the issue. I got the slip light to flash once but no brake application from the VDC. Mind you I was swerving like a madman and there was some minor gravel as I passed a dirt road exit so I'm thinking there was some actual slippage going on.
It could be the tires are fresh, psi was too high and the VDC is just way more picky about what the car does than I am. That doesn't fully explain why it only stepped in while turning right in semi-slow turns though so I'm pulling of the air bag to check the steering angle (gonna compare markings with my old one) and play with the sway bar tomorrow.
i8cobra, if OP did have an issue where his steering angle was off and the shop that did the alignment fixed it by adjusting his toe back to spec, we would know this by looking at the initial/pre alignment specs right? A before and after would show OP that his toe was off and that the alignment was whack to begin with? could save OP some time removing the airbag to look.
It would be obvious if the toe was off that much before the alignment. The steering wheel would be turned a few degrees while driving straight. It would also depend on how many times it's been aligned since the steering wheel was removed.
icobra8 mentioned those types of scanners are not cheap. my searching found everything above the 1k mark. Maybe a shop could let you hook it up to check if you knew the shop well enough, given they have something on that caliber.
I did some digging and found a picture from my snapchat where I could see the alignment screen in the background. Applies some CSI "enhance" and this is what I found.
This is before he aligned the steering angle, however he was adjusting camber while I took this snap so the measurements are a bit off in general and I don't know if the steering wheel was centered in this picture.
He did take out some of the toe in and I think he set it quite neutral because he insisted Z's need that "dartiness and slight oversteer"..
I'll remove the airbag tomorrow-ish and check the teeth of the wheel/column.
I did some digging and found a picture from my snapchat where I could see the alignment screen in the background. Applies some CSI "enhance" and this is what I found.
This is before he aligned the steering angle, however he was adjusting camber while I took this snap so the measurements are a bit off in general and I don't know if the steering wheel was centered in this picture.
He did take out some of the toe in and I think he set it quite neutral because he insisted Z's need that "dartiness and slight oversteer"..
I'll remove the airbag tomorrow-ish and check the teeth of the wheel/column.
FYI you will need a T30 security hex/nut to remove the airbag.
04-17-2020, 11:55 AM
VDC kicks in on right turns, but why?
but got nothing other than the cyl 5 misfire I was expecting. 
