kelp

After an engine replacement, which involves separating the body from the chassis, my 06 Z06 will jerk to the left and right. This happens every 20 min or so. The car also "tracks" the road, small but noticeable, when there is no uneven pavement. At highway speeds this is very unnerving . I imagine at track speeds, this will cost control.

The active handling (AH) is turned off via unplugging the steering sensor, which has worked well for years. I checked the suspension, steering rack wheels and brakes. Everything is tight. I have no idea what could cause this. It may be something else unrelated.

There is some occasional banging in the passenger rear wheel area, but on my lift I cannot see anything loose, sway bars and so forth. Any ideas?

Please keep in mind this thread is about keeping the AH disconnected for the track.

kelp

In the back, the muffler is very close to the sway bar, that may give the bang sound.

After the repair I noticed the steering wheel was angled just slightly to the right, but the steering is very tight. I imagine the steering has to be detached somewhere for this job but if something was loose it should feel like it.

Ahrmike

toe changes in the suspension can cause severe tramlining issues. A good alignment might be required?

FortMorganAl

Disconnecting the steering sensor will not disable active handling. It will make the computer think there is something drastically wrong but the computer will still try to do its best to do what it thinks you are asking it to do. By disconnecting the steering position sensor you may just be introducing noise into the system especially if you have added resistors to keep the computer happy and there is a loose connection. Why not just hold the button to turn off AH and traction control on the track?

psp6158

I'm thinking they didn't mark some threads when they took things apart, i had mine aligned with no issues...

mikeCsix

For track days I keep them both turned on. They won't activate if the slip angles are kept equal at all 4 corners and will help you recover if you screw up.

Dcasole

buckmeister2

I assume you have taken it back to the folks that did the work???? What did they say?

cclive

Disconnecting the steering position sensor is not the way to disable active handling.

ocboy

If your vehicle wanders all over the road, then it's most likely an alignment issue.

torquetube

Track guys disconnect the steering wheel sensor (which _does_ disable AH) to prevent automatic AH reactivation in the event of TPMS malfunction.

You can read all about it here: https://www.corvetteforum.com/forums...-defeated.html

Scooter70

Yes, disconnecting the SWPS is the simple way to disable AH.

Did you get an alignment after the engine replacement? What were the specs? It sounds like something is funny with the alignment or inner/outer tie rod ends.

IansInGarage

If you/shop lowered either subframe you have to get a new alignment. Do this and report back.

WulfLS3

You say the car will jerk left or right, does the steering wheel jerk or the entire car move around? Alignment issues will cause problems all of the time, not at 20min intervals. If the steering jerks, check the hoses for damage/kinks and steering pump operation. The steering rack internal valves may be failing. If the entire car moves around, even though the bolts seem tight, chassis or suspension arm bolt holes may be elongated or mounting points may be damaged. Are the suspension bushings and ball joints ok?

FortMorganAl

Studied this a bit and have to call , I'm on thin ice here with several track guys saying it works but I see nothing in the manuals that would support all the claims that this fixes an issue with TPMS failure which is why they are doing it, not to just disable AH which can be done with the button. The linked thread is about pulling the sensor so that after pushing the button to disable AH, it doesn't come back on if the TPMS system fails. Yes, they say it disables AH from the start which it may or may not do in the case of the OP of this thread. Pushing the button with the sensor connected will disable it in the OPs situation.

kelp

The verdict is in. Discussions with the mechanic reveal he had a hard time realigning the splines (I am not sure where this exactly is or I would fix it myself) when he reassembled the steering. It appears thus that it slips one cog and that is responsible.

Electronics can be so distracting - frequently blamed and in fact usually at fault.

Thanks to all!

Ahrmike

if the steering angle sensor is off enough for the computer to trip the brakes, you should trip the brakes a few times before the computer sees its a "faulty sensor" via yaw sensor input... and locks out the SAS.

At least thats how it was when my SAS was broken. Its possible that the angle difference is so small that the computer is being confused... but with the SAS off, it should not be doing the jumping thing.

I still highly suspect that your alignment is off.

thevpops

I experienced "auto-steering" as well. I was under the GM Certified Warranty (bought my Vette used GM Certified). I received ABS service messages. Also, traction control messages I think. It was very annoying. Eventually, the main culprit was the steering angle sensor (defective). Maybe they also replaced a control unit. But for sure, they had to replace the steering angle sensor. That issue is long gone.