Vibration at neutral

[Minas George]

I have the euro (manual )edition of the CX7 so decided to post here instead of the respective thread..

I have some (minor) vibration issues at idle on neutral.
When the car idles at ~ 700rpm I feel engine vibration on the seat and on my thigh. When I rev up on netral it goes away, but when I reach 2.000rpm (almost exactly there) the vibration suddendly becomes MUCH stronger. Rev over 2.000rpm and the vibration goes away...

Dealer says its normal, but the other 2 test drives I tested did neither...

Any ideas? Car has 7.000km.. flywheel was changed under warranty, but still does it..using 100octane gas for the last 2.000km ...

Thanks...

 

[MSP #167]

how many miles on the car? Prob a shot engine mount.

 

[Minas George]

how many miles on the car? Prob a shot engine mount.

Car is new..Jan '08 , 7.000km
Overall..: slight vibration on seats @ 700rpm & neutral
vibration (not excessive but more than noticable) on whole car on neutral @ 2.0xx rpm exactly, that goes away on higher or lower RPM

Single STRONG body shake when shutting down.


Dealer changed the dual mass flywheel, but no change.

 

[MSP #167]

could be normal, but what you are describing is kinda weird with such low miles.

 

[Rubasu]

possile bad mount

 

[Minas George]

mount? heat?

If its a mount, it would be a defective mount and not simple wear out at 7.000km , right?

This vibration seems to more evident when the car is warmed up well. But its not the fan...

I am trying to find out the relation between the vibration at idle / neutral, strong harmonic? vibration at 2.000rpm that goes away at higher / lower rpm and the shake at turnoff.

ideas?

 

[tiagotiago]

If its a mount, it would be a defective mount and not simple wear out at 7.000km , right?

This vibration seems to more evident when the car is warmed up well. But its not the fan...

I am trying to find out the relation between the vibration at idle / neutral, strong harmonic? vibration at 2.000rpm that goes away at higher / lower rpm and the shake at turnoff.

ideas?

Regarding the motor mount, yes it very well could be defective. Several 2007 Mazdaspeed 3 in USA(more info in the "Welcome" section of this forum) were recalled because of this issue, maybe your mount has a similar defect.

Considering the vibration occurrs in the engine's "lower" frequencies, the vibration could well be of some resonation going on. If I remember correctly, the turbo starts to spool up at about 2300 RPMs, so maybe it's also adding some vibrations at low speeds that then dissapear when it's spinning at it's proper speed. Of course the engine might be tuned slightly different for the CX-7's application, causing it to spool up at different RPMS.

Hope you find out what's going on. Keep us posted.