FluKy15

I have absolutely no idea what's happening to my car, but it's freaking me out. My car vibrates like crazy at all times that it's on. At idle is when it's the worst, and the vibrations change as the rpm changes. If I'm moving along at 50 and press the clutch in, the car rolls as it should, but the vibrations from the motor are still there. I also suffered poor gas mileage from this issue. Does anyone have any ideas on what it could be?

darcyw

does the engine sound like its firing on less than 4 cylinders? I can recall pulling a plug wire on my civic and because of the inherent inbalance it shook…no REALLY shook.
Because of resonant frequency, the shake will likely change based on RPM.

when the car is rolling and shake could be an out of balance wheel…but that's an obvious one.

good luck there.

darcy

FluKy15

I forgot to mention that there is no check engine lights, and the car has the full amount of power and torque that it usually does.

I've narrowed it down to either being a motor mount or an unbalanced flywheel/clutch assembly. The motor mounts seem fine, I dont know how to test for the flywheel...

starchland

Motor mounts
Is the car stumbling or anything? Pop the hood and watch the motor while you start it up and rev it and see if there is excessive movement

iamxpl

check your motor mounts and trans mount as well.

iDomN8U

Spark issues can cause engine shake as you described.

Swap out a coil-pack, apparently they can go without a CEL.

But even before that, you can test which cylinder might be the culprit by unplugging injectors one at a time (don't do this for very long). When you pull the plug, it should get worse, if not then that's probably the cylinder with the issue.

myflys2k

When my passenger engine mount was broken I didn't notice any vibration. I'm sure my mount was broken for years. Accelerating off of a light would chatter my new clutch and that's when I found the engine mount was toast. The fact that the engine vibrates at all rpm and has normal power makes me think it's something out of balance.

Obviously the mounts are the easiest to check so start with that.

https://www.s2ki.com/s2000/topic/803...r-motor-mount/

Look at the first pic in that thread. This is where my mount also broke. Just looking under the car won't help. Visually from the bottom of the car my mount looked fine.

vtec9

Dead cylinder (total misfire) will cause violent vibrations, but also a noticeable drop in power since one cylinder isn't firing, and it should trigger a CEL. I'd pull codes to see if there are any pending.

FluKy15

There are no codes to pull, and the power is all there. Did you read my posts?

vtec9

My post was to say; doesn't seem like misfiring since you don't meet the symptoms, but pending codes don't trigger a CEL until they move past the 'pending' state, so it may be worthwhile to see if anything is pending. yea..