My 2013 GS has had a very stiff ride since I got it last year. It had 7855 miles when I got it and now it has about 8600. Tour and Sport feel exactly the same, both are extremely jarring and harsh. Last summer I took it to the dealer who told me my shocks were leaking and quoted $3800 to replace them. I declined. Last fall, I put new tires on, which made the ride quieter, but not less harsh. I asked @Jim Mero what he thought and even sent him pics. He told me to wipe them down and see if they are wet. I’ve read the same thing here in other posts. So I got it up in the air, wiped them down and checked them for shipping blocks and also felt around the shaft seals to see if there was any wetness. The shocks are dry.

Today, I got my VX Nano set up and connected to the car. I went into the electronic suspension control section and looked at the height sensor voltage because @Dano523 suggested that in another thread. They are all a little over 3 volts, except for the left rear, which is about 2.5 volts. But the really weird thing is that for some reason, I decided to blip the throttle and I noticed that the Damper Actuation Command on the rear shocks went up! Why in the world would that happen? I assume that means voltage is being applied to the shocks. I am attaching a link to a video of it.


Any help is appreciated.

 

L and R front shocks have no coms to the F55 module, so that wiring needs to be checked. With luck its the the final top of shock clip connector that got broken (center piece if not pulled straight up), and they need to be replaced.



Note, the rears shocks are fine, since you are can see the swing in voltage as the car is sending more/less voltage to them (how is controls the shocks).
Myself, since the F55 module is just above the ECM, will pull it's connector, take the front shock wires pins per shock, ground those two pairs out with pieces of paper clips , then pop the shock top connector to use the meter leads probes on the innner barrel/outer connector, to make sure that I am seeing a dead short on them. I can post a F55 connector diagram, but if you look the wire connector wires for each front shock, easy to get the wire color pairs that way as well.

Also, take a look at the F55 mode, and make sure that it switching in the BCM when you change the mode selection. Hence Touring to Sport, and back again on the reverse of the switch. If the selector switch is bad/not connector default will be touring mode.

Next is to put the car on level ground, and either measure from the wheels to tip of fenders to get a rough corner balance that way from the stock dimensions conversion, or break out the scales to get the car corner balanced dead on the money isntead.
Note, not uncommon for the fender lip to not be perfect from side to side to the chassis, and when GM builds the car and it goes into the final check booth that has the 4 point scales, ride height bolts get tweaked there to get the corner balance in check.

Once the car is corner balanced and still on level ground, then need to go after each of the ride height sensors to loose there mounting bolts to tweak as needed, to pull each back down to 2.9 Volts when bolted up tight again. If mounting bracket tweaks does not take you all the way, then the snap on length rods can be pulled to spin them more out or in as needed as well.
Attachment 48333810

 

To add, what we are seeing is the VSS is not showing any speeds, since the tires are not rotating.
We are getting voltage reading from all 4 ride height sensors, but all out of range, with either the car not corner balanced correctly with the car lowered, or if it is corner balanced, someone did not go back in to adjust them back to 2.9 volts. And the reason that we need all of them to read 2.9 volts, is the ride height sensors are not really linear in there movements, and when the voltages are off, the F55 module is seeing the change in voltages not correct.

The last one is the activator damper coms, and that is the amount of voltage that F55 module is sending to each shock. The higher the percentage, the higher the charge in the shock to slow the fluid down through the piston passages. So reving the motor will change the stance of the car, which is picked up by the ride height sensors, and them F55 module sends out the voltage to the shock to slow the fluid down through the shock pistons. So Ride height sensor have voltage readings in the first place, but F55 is not able to send voltage through the front shocks due to a problems (my guess, cracked top connector caps that someone broke the barrel connectors out of them, or problem in the wiring itself from the F55 module connector, to wire connector at the shock side, that connects to the shock top cap connector).
Note, when you have the top shock cap connectors off, you can use the meter to check for resistance through the shock as well.

How the MRC shocks,

 

Lots of good info, thanks! But if the front shocks have no continuity, why isn’t there any codes?

 

One more question - where in the Tech 2 menu do I look for the switch between Tour and Sport modes?

 

Will be in both the BCM and F55 module data.

The selector switch goes to the BCM, and the BCM sends the digital signal to the F55 module to pull itself out of the tour mode.
Again, switch not working or connected, default in the BCM is touring mode.

 

Just got back in from the garage. I was able to find it just by poking around in the menus. The switch works. I can see it going from Tour to Sport. I also was able to cycle each shock using the Damper Actuator Command for each shock one at a time. Each responded with 95%, so I’ve got good continuity. I did it with the car in run mode, but not actually running, and I could hear a high pitched sound each time.

I also stood on the door sill and I could see the height sensor voltages change. It also changed when I got in the car. So now I’m thinking you are right that the height sensors are not calibrated correctly.

 

Again, before you go after adjust the ride height sensor, would do a full corner balance, or at least bring the fender lips back in check if the car is lowered.

Base line at oem height is 26 1/4 for the fronts from ground to lip of fender on level ground, while rears should be in the 28 1/8" range.


So if car is lowered, and you want to do a fast/less that precise corner balance to the car, take the front differential numbers to see how much it was dropped from the OEM height, pull that from the rear OEM numbers, to set the back heights (via the ride height adjust bolts on the trans springs). Once you have this at least close, then you can after the ride height sensors to bring them all back into range of 2.9V with the car on level ground.

And again, not uncommon for the fender lips to be out 1/4" from side to side compared to frame to ground (again, level ground, which will be hard to find since most slabs are not poured flat), but could use the frame height off the level'ish ground to get a little closer instead.

https://suspensionspot.com/blogs/new...rner-balancing

 

So, the front fenders are at 26 1/4" on one side and 26 1/8" on the other (seems close enough to me). The rears are both at 28 1/8", so the car isn't lowered. I will have to schedule some lift time at the local DIY shop so I can adjust the sensors to the correct reading to see if that makes any difference in the ride in the two modes.

 

Coming back to update my old thread. Yesterday I installed my Jim Mero mag ride module. The car is so much better to drive now! It rides great. Still stiff, but noticeably smoother over bumps and pavement seams, etc. it should have come from the factory like this. I’m surprised that Chevrolet let these cars leave the factory with such a bad calibration.

I’m pissed because last year, right after I got it, I thought something was wrong because it rode so badly and I couldn’t tell a difference between the two modes. So I took it to a dealer out here in California that everyone said was the only place to take your Vette. I told them about the mag ride being stiff and they tried to sell me 4 new shocks for nearly $4k, because mine were “leaking”.

Anyway, thanks for the input. Just wanted to let everyone know what the resolution was.

 

According to GM, the corner balance (stock fenderwell height) should only be done with a full gas tank and before checking/setting the 2.9 volts at each shock.

 

Just a FYI, but that stock F55 setting that came with the car that you are bitching about, that was Jim's too (GM corp did have a bit of say so on it's final setting as well).

 

Well, Jim has said that they learned a lot when they developed the C7 mag ride and he applied that knowledge to his updated C6 calibrations.

 

Could be, but believe that it started with lessons learned all the way back in 2008.

https://nurburgringlaptimes.com/chevrolet-corvette-zr1/

 

Jim did his Super Sport/Track package for my 2012 GS. I did not like the stock tour setting and always used the sport setting.
HIs Super Sport setting is even better than the stock Sport and the Track gives me an even better feeling ride.
I use the Super Sport for rougher roads and the Track on smoother or twisty roads. I love this combo. Way better feel than stock.
I did some testing on this for Jim by switching back and forth between several different combos and settled on this one. (Super Sport/ Track)

Chuck

P.S. I also could not tell any diff with the stock Mag Ride settings unless the road was rough.
Also I am running 19 and 20's.

 

I know this is a semi old thread, but I wanted to jump in here and ask. How many miles does your magneride suspension have? And if they failed, around what mileage did they fail and what differences did you feel?

 

Are you asking me? Mine are fine. I wiped them down with a rag and lifted the boots and felt for wetness. There was none, so I got the calibration from Jim Mero. I just had the car at the dealer last week and they said nothing about the shocks that supposedly were bad back in 2021.

 

Sure, you or anyone with Magneride. I'm just trying to diagnose if mine are bad or not. 91k mile Grand Sport. I'd prefer to stick to Magneride since mine already has it and its more advanced tech than go to standard shocks and deal with the delete process for the magnerides.

 

I think mine are fine. I have not ridden in any other C6 with mag ride, so I have nothing to compare mine to. My car only has 11k miles.

 

Were there differences between the years of the C6 regarding the magneride suspension? As in did 05-2008 have different magneride than 2009-2013?