Hit a decent size pot hole a few months ago (driver side front tire then rear tire) and now noticing some seat vibration at high speeds 95+. No shaking of the steering wheel and no noticeable vibration at below 85mph

From visual ball joints look ok and snug. All rods look snug and in normal shape. installed new coilovers, new wheels/tires, new front UCAs recently and alignment within spec. Any other ideas issue could be? No noise from wheel bearings, axles?

Thanks in advance

 

There are a few threads on this in the is250 forum. Could be the frame/I body is bent. Guys have hit pot holes and bends show up in the roof near the sunroof.

 

+1. What he said for sure.

 

Yours vibration is probably coming from hitting the pot hole.

My car has had some vibrations lately due to the fact that I haven't been driving my car much. I think when the tires are cold and the car has been sitting, its causing some flat spotting on my tires? I don't know...

 

Although I have not done this on this car, I have jacked up the rear of a car from the pumpkin and put it into 1st gear. Let the wheel rotate and lock your eye on the edge of the rim (inside, then out). It should be completely steady. If it's wobbling at all, bent rim. Do the same for the front driver's side except you will have to spin it by hand. I'm not sure if the computer will freak out but maybe not.

 

It won't. I validated the speedometer uses the rear wheel sensors only when I put the car on jackstands and put it in gear. Nothing bad happened at all.

 

I believe the speedometer gets its inputs from the VSS located on the output shaft area of the transmission, so yes the speedometer does get its speed readings from the rear wheels. It won't mess anything up if you spin the front wheels

 

No. The speed signal comes from the skid control ECU. It gets data from the rear wheel speed sensors, not from the gearbox.

 

I would think if the speedometer used the rear wheel speed sensors, there might be a variation in speed while cornering, so it would have to average both inputs into one? The VSS only reads one certain input, so I supposed thats where the speed reading came from. Also, the writing in the image could be wrong, as it may actually just be a generic text copied from another vehicle. And the skid control ECU certainly only gets it's speed inputs from the wheel speed sensors

If there is something in TIS about this, please do elaborate

 

its salvage now, just sell it and get your GT3 lolz

 

i think it might be my inner tie rod, which could have been slightly bent from the pothole, which i would only notice the slight vibration at high speeds

 

Pin 11 of the Skid Control ECU is the output for the speedometer. The part description you are looking at is incorrect. This has been true since the '06 2IS with VDIM.

 

I would say test the theory with the spare tire, but it's not rated for HIGH SPEEDS.


Maybe you can borrow a full size wheel to test the theory..

Joe

 

Yeah i can't do it with a spare since it won't be felt until 100+. I tested 2 balanced sets of wheels/tires and i think i narrowed it down to either passenger front right inner tie rod or control arm. since my set up is dial in right now and its not often i need to go that fast i'll wait for replacement after new set of tires that way i'll need to realign. Thanks for the feedback so far.

 

Did you ever figure it out? I’m having this issue now. I have a 2008. It shakes/vibrates at speeds 100+ mph. Everything is smooth nothing noticeable for any speeds below 100.