Date: Thu, 27 Sep 2007 18:42:03 +0100 From: "Charles C." <c.k.christacopoulos.removeme.nospamee.ac.uk> Subject: Re: Intermittent engine vibration
Doug Schwarz wrote: > I have a 1995 900S with an intermittent engine vibration. It appears to > be related only to engine speed and it comes and goes. Here are my > observations: > > 1. I notice the vibration mainly through the gear shift lever and the > gas pedal. > > 2. When it first started it would exist for an entire trip and then be > absent for another entire trip. Now it seems to start and stop during a > trip and the amplitude varies, i.e., it's not the same intensity all the > time, but you definitely can notice when it's there and when it's not. > > 3. It feels and sounds a bit like a hole in the exhaust system, but the > character of the sound does not change with the throttle. It will be > present at idle. If I get up to speed, press the clutch and then rev > the engine back up to the cruising rpm the vibration feels exactly the > same. As a result I conclude that it's not related to the tires or > other drivetrain components after the clutch and also not a hole in the > exhaust system. OK, a different take. If it sounds like an exhaust assume it is exhaust related. If you open the engine hood (bonnet) can you hear that sound? Anything at the exhaust manifold? A blowing head gasket (got to be blowing badly) would produce some hishing(?) sound. If you took a look at the sparking plugs do they all look the same (brown/grey colour). Is there one or two adjacent plugs which are different to the rest (oily, black or wet). Too far fetched, you should be able to tell from luck of power. > > 4. It seems to peak in amplitude at about 3200 rpm. > > 5. The other day I did quite a bit of driving around town on a hot day > (about 82 deg. F) and the vibration was absent so maybe it's temperature > dependent. Not enough fuel so on a hot day it had enough on colder days not so ... should not matter when the engine is at working temperature tho. > > > I called the local dealer and the service advisor said he'd never heard > of anything like that before. I didn't get a chance to talk to a > mechanic. > > Any ideas? Thanks! > All I can say is have another go at describing the problem (using different words). Cheers Charles PS. Wild guess, flywheel/clutch issue. But should really change with revs. -- Please remove _removeme_ to reply.
