I have developed an engine vibration at 4,000 + - 200 RPM and I am running out of ideas about how to minimize it. I feel the vibration has become more noticeable after doing my water pump in which I loosened the four motor to carrier nuts and the cat pipe mount clamps/bracket.

First off I have urethane motor mounts; wevo mounts with black (softer) pillows.

I have have loosened and re-tightened all of the nuts/bolts for engine to carrier (34 ft*lbs) and carrier to chassis (40 ft*lbs) while the engine was supported by the jack, and the vibration is still present. Is there a procedure to this process or something else I may be doing wrong (too tight or too loose) exhaust clamps or mounts?

 

Thats what the wevo mount do.... stiff motor mounts (hence pronounced vibration). Maybe the vibration was always there but not noticeable on the soft OEM mounts.

Maybe you should go back to stock mounts and see if its still detectable...

 

This was not from just changing the mounts. I have always had the wevo mounts, but the vibration was never this bad... I feel like it is related to the cat pipe exhaust clamps, which secure the exhaust to the engine carrier.

 

I had an annoying engine vibration at 2000 rpm and traced it to the exhaust system. By installing the radiator clamps shown in the pic I eliminated it. Not the most sophisticated remedy but it works and I a really am enjoying the car much more. Silky smooth, it’s like a different car. I wish I could find the root cause. I have replaced motor mounts, 02 sensors, spark plugs, DMF, tried different mufflers, etc. the only thing that worked was $5 worth of clamps. I was thinking of replacing the headers but am afriad of snapping the bolts on the head.

I found similar characteristics with other 2002 to 2004 models (6sp or tip) but not as severe. I am surprised that more members are not complaining.

P.S. PM me if anyone is interested in o2 sensors (before the cats) and motor mounts with only a few operating hours. i removed them when they didn't solve the problem.

 

I never noticed any of that on mine.... so I am really curious as to
what would cause this vibration at a specific RPM!!

Could you describe the vibration in more detail?
1. location
2. noises? loudness?
3. how long ( if you stay on that RPM, does vibration remain steady?
that would make it easier to troubleshoot)

Is it possible that it is coming from a slightly warped flywheel?

 

Not really. I will try loosening, adjusting, and retightening more of the exhaust coupling and mounts; perhaps some dampening material under the exhaust clamp will help too.
I am fairly certain the problem is a resonance of the exhaust pipes at that RPM.

 

What about a root cause for the vibrations though?

 

I wish I could pinpoint the root casue. After all the playing around, replacing parts,etc. I think what I feel is the header/cat assembly vibrating at its natural frequency. When it is restrained with the clamps it is silky smooth.

The vibration could be felt very slightly at about 1000 rpm within a very narrow band and the again at 2000 rpm within a narrow band but it was much more noticable. THere were no strange noises. It was a steady vibration as long as you keeped the engine at 2000 rpm. It could be felt stationary as well as the lower gears. It seemed to be more pronounced when decellerating through 2000 rpm. At first i thought it was a defective dual mass flywheel and had it replaced. THere was no change. I checked the motor mounts and transmission mount and found nothing wrong. I disconnected the VarioCam Plus actuators thinking it had something to do with it but that made no change either.

 

When you replaced the flywheel, did you keep or see the old flywheel?
Just playing devil's advocate for a moment but what if the flywheel
is still defective?

The flywheel is the main part dealing with vibrations you are describing, in this case.
I maybe wrong, though.

a bad plug or bad electric connection also cause vibrations, but .... geesh!
Good luck and keep us posted.
J

 

the dmf replaced under warranty and don't have it. yes, i wondered if the replacment was defective but i noticed that some tiptrinic cars had similar vibration but to a much lesser degree. So i ruled that out.

i replace the spark plugs since duramtric software detected a missfire. also, the engine runs too good otherwise to have an ignition problem.

i thought maybe it was a mixture problem and this is why i replaced the o2 sensors. all the mixture correction fators check out ok as well.

the next item on my list is the camshaft deviation. bank 1 is 4 degrees and bank 2 is 0.4. the allowable is 6 but i still plan to look into it.

 

Does the Durametric software let you see the camshaft deviation?

 

yes. it reads a lot of info.

 

Thanks George. I just ordered it on line.

 

George
Do you know where can I get all the detailed info for camshaft deviation
and other functions in the Durametric? The manual is very limited.
Thanks

 

Have you removed the belt to see if it eliminates the vibration?