Paul...
We've got a bit of a problem with my RX8 that the dealer is scratching
his head over. Thought I could bounce it off the group and see if
anyone here has any ideas.
Background...I took it in last week to have them check the brakes
(felt
like warped rotors...it was) and while test driving it, the mechanic
thought that the clutch didn't feel right either. So, (from the
invoice), besides the front rotors, front and rear pads and rebuilding
the calipers, he replaced the clutch release collar, cover, clutch
disc,
oil seal and a needle bearing.
I'm very happy with the work they did, and the brakes and the clutch
feel better than new.
But, something new has cropped up. I noticed it the day I picked the
car
up and took it right back to them.
The best description is that it feels like the p-factor in an
aircraft.
When accelerating under load (clutch engaged, going up a hill, or
downshifting to pass, etc...) the car pulls to the left...BUT the
steering wheel doesn't turn! Not even a hair! And I don't have rudders
on that bird to hold it straight! And, when the clutch is depressed,
and
the wheels are just idling, and I accelerate the engine, it doesn't do
it...so it's not really p-factor.<G>
If I do try to correct the pull so the car stays in lane, then release
the clutch to shift, or back off on the accelerator, it will snap back
to the right. If I don't try to correct it with steering,then on
releasing the load, it simply straightens out in whatever lane it's
in...again, the steering wheel never turns even the slightest (unless
I
tried to correct it, of course, which is why it jumps back to the
right
if I've corrected the drift with the steering).
Even using just the cruise control, taking me out of the equation
completely, as it accelerates to climb a hill, it drifts left,
reaching
the top and easing back on the gas, it straightens out...again the
steering wheel doesn't turn even a hair. If I release the cruise while
it's under load, it jumps back to straight travel...and as always, no
steering wheel turn at all.
The mechanics at Holtz can also get it to do it, and the car spent all
day today getting alignment checked, and rechecked by several
different
mechanics, removing all the parts they installed, reinstalling them,
etc., but they still can't get it to drive correctly.
The dealer's service people are baffled (they also service Audi and
Porsche). They've never seen this before, and don't know what's
causing
it. Jason (the mechanic) called a couple of other Mazda shops across
the country and some others out west (in your direction) he knows who
have experience in racing Corvettes, as well as the RX8s and they,
too,
are baffled.
They agree that it is dangerous to drive like this, and have given me
a
Mazda 3 loaner until they figure it out.
Does anyone have an idea what may be the problem, or where else to
look
for an answer? If I can give them some clues or ideas, then we might
speed this along.
BTW, the tires are brand new (only about 1000 miles on them), and the
car wasn't doing this before I brought it in last week.
At this point, no suggestion is too ridiculous! <G>
Harley Dixon
Obviously there is something wrong with the electronic
rack and pinion. There is a torque sensor in there that
may have malfunctioned. It sends data to the steering
computer (EPS) and the EPS then applies the appropriate
amount of polarity and voltage to the rack motor.
The torque sensor or EPS could be getting voltage spikes
from some of the other electrical devices in the
car. Perhaps the grounding wire is loose.
Get the dealer to swap it out and see if that
fixes it.
BTW Harley I will be needing new tires on my RX8.
I understand the ride on the tires you bought is much
better than the stock tires. Tell me again what brand
and size did you buy?
Paul Lamar ...No rotor no motor.
A real interesting behavior. Has anyone considered a bad-going
differential.
I dont know what the RX8 diff looks like, but if you have unequal load
distribution to your drive wheel, you will see what you described.
FWIW.
Richard Sohn
N-2071U
Doesn't this car have the "active" rear suspension that is designed to
be compliant in certain directions under certain loads ?
Maybe one of the rear suspension bushings was damaged by improper
jacking or... just decided to wear out at this time.
Bruce Toski
Paul,
I'm betting on the tire solution. I chased this very problem on my RX7
year
ago. The tires were parked the same, but after pulling them off, there
was
an obvious difference in the two tires. And it wouldn't effect the
steering
wheel. Its just the rear of the car trying to pass the front.
Bob Mears
I am beginning to agree with Bruce Toski or Richard Sohn.
Torque steer from the left rear suspension. Left rear tire is
toeing in under thrust loads.
Shot rubber bushing or ball joint or adjustment cam in the
lower lateral links. Could be the forward or aft link outer
ball joint or inner cam adjuster or rubber bushings.
Mechanic forgot to tighten a bolt when he aligned the
the rear suspension.
Locking or limited slip diff. problem.
Paul Lamar
Harley,
My '65 Shelby GT-350 (with Detroit Locker diff) will act like this if
the air pressures in the rear tires are not exactly the same. Also, if
they had the tires off during the clutch work, and then put them back on
different locations may cause it to behave like you described. Just a
hunch.
Mark S.
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