Resonation in the car above 4k's

Mitco39 · 06-26-2013, 08:45 AM

Hi guys,

The car recently developed (right around the time I did an oil change, not sure if it is just a coincidence or not) a resonation through the whole interior when off the throttle and above 4000 rpms. Its most noticeable when you are slowing down a bit aggressively and downshifting to about 5-6000 rpm. I have spent the better part of the weekend going over everything with no luck.

It also doesn't seem to start right away, I have to drive the car for a couple miles before it decides to do its thing. You cannot hear it from outside the car (had a buddy check beside me on the road) which points towards something rubbing somewhere possibly.

I spent a couple hours under the car last night looking for anything that could be rubbing with no luck. Has anyone ever had an idler wheel go out on the belt?

The fact that it resonates makes it very hard to determine where the sound is coming from. It does appear to follow the rpms. Maybe an engine mount? How would one tell if one of those let go? Since it only happens on decel (atleast from what I can hear, the car gets pretty loud excelerating) it could be a mount on drivers side I guess. But this wouldnt explain it not doing it right when I start driving it.

Just looking to see if anyone has experienced this on their Z's.

Thanks guys,

Mitch

06-26-2013, 08:45 AM	#1 (permalink)
Mitco39 A True Z Fanatic Join Date: Aug 2012 Location: Edmonton Alberta Canada Posts: 2,089 Drives: 40th 370z Rep Power: 132	Resonation in the car above 4k's Hi guys, The car recently developed (right around the time I did an oil change, not sure if it is just a coincidence or not) a resonation through the whole interior when off the throttle and above 4000 rpms. Its most noticeable when you are slowing down a bit aggressively and downshifting to about 5-6000 rpm. I have spent the better part of the weekend going over everything with no luck. It also doesn't seem to start right away, I have to drive the car for a couple miles before it decides to do its thing. You cannot hear it from outside the car (had a buddy check beside me on the road) which points towards something rubbing somewhere possibly. I spent a couple hours under the car last night looking for anything that could be rubbing with no luck. Has anyone ever had an idler wheel go out on the belt? The fact that it resonates makes it very hard to determine where the sound is coming from. It does appear to follow the rpms. Maybe an engine mount? How would one tell if one of those let go? Since it only happens on decel (atleast from what I can hear, the car gets pretty loud excelerating) it could be a mount on drivers side I guess. But this wouldnt explain it not doing it right when I start driving it. Just looking to see if anyone has experienced this on their Z's. Thanks guys, Mitch __________________ 2007 Chevy Duramax - EFILive Tuned By Me 2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her My Build --> http://www.the370z.com/members-370z-...39s-build.html