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:
I notice the vibration mainly through the gear shift lever and the gas pedal.
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.
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.
It seems to peak in amplitude at about 3200 rpm.
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.
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.
Ignition, any vacuum pipes. There is a possibility that the vibration is there after 3200 rpm but its frequency is such that you can't tell.
Does the car have a Direct Ignition cassette? :-)
Sorry, I had to have mine replaced recently (1997 9000) with the symptoms being mainly a misfire (there is vibration for you) and having got the new one I have realised that the car was rough for some time now ... but I could not tell.
One approach is to drive the car until it gets worse.
Yes, the vibration is there after 3200 rpm, it just seems to peak in amplitude there.
I immediately suspected an electrical problem of some sort because of the intermittent nature, but the service advisor said that the "check engine" light would come on if one of the spark plugs was not firing.
No, it's the 2.3L non-turbo and there is no mention of the DI with this model.
Thanks for your comments (and Graham, too). I get the impression that the vibration would be far worse if one cylinder was not firing at all, but I will investigate further. There doesn't seem to be any loss of power and the car is perfectly drivable -- it just vibrates.
Have you checked the inside of the distributor cap to see if it's clean. Many of the non-turbo's (including my 1995 900S) have a leaky distributor shaft seal. Mine's done it for years. It's only a little oil that gets by, but every a few months it accumulates and I notice the idle is less smooth and it's more difficult to start off from a stop(5sp-M/T). Lately I just pull and clean the cap at every oil change (3k miles) and that works fine.
Thanks for the suggestion. As it so happens I have just come in from having done exactly that! Yes, there was some oil in there, but not very much. I cleaned it up and took a short test drive, but the vibration was still present.
I visually inspected all the HT wires and they look to be in quite good shape. I'll have to look at the service records to see when they were last replaced. I realize that you can't tell if they're faulty just by looking at the outside, but if they're new they're most likely okay.
In general, the vibration seems to be less frequent over the last couple of days so I may have no choice but to wait until it gets worse. I don't actually drive much (often less than 100 miles per week) so that may take a while.
Today I replaced the coil, distributor cap, rotor and all HT wires. The spark plugs themselves were replaced at 95k miles (currently at 113k miles so that's 18k miles ago). No change in symptoms. Well, at least now I know what is *not* causing the vibration.
As an aside, the rotor was very hard to remove. I literally had to saw and crush it to get it off and then lightly file the shaft to remove all the bits that were still stuck on. Weird.
Any other suggestions anyone? Charles suggested leaking vacuum hoses -- how would I check those? Could an engine mount fail intermittently?
For those just tuning in: I have a 1995 900S with an intermittent engine vibration. It doesn't matter whether the car is moving or stationary and it seems to peak in amplitude at about 3200 rpm.
One way of checking for leaking hoses (sucking rather than blowing) is - I am told - to have the engine at idling speed, and spray carburettor cleaner liquid (gas) to the various hoses and connectors.
If you work slowly round the engine, if you find a leaking (sucking) point, the revs of the engine will increase.
Another possible cause of vibration would be a misfire caused by a leaking head gasket. If (I guess) the misfire is bad enough for you to notice the vibration then you should be able to notice a luck of pulling power. It could also differ between a cold and hot engine, and certainly under the heavier loads.
Engine mount. Would have been my next suggestion ... but it should be a lot more obvious or different with the car in motion. Accelerating or decelerating would move the engine and change the vibration.
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Engine timing out? Anyone? How does the timing work on this model (sorry my knowledge is as far as early c900s). Does it have points in the distributor or electronic gadgetry?
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.
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.
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.
OT: had an Mitsubishi -91 Colt GTI 1.8L 16V ( pre GDI engine ). once one ignition wire was bad, runned very bad around 2000-2200rpm. no problem running under or over 2000rpm. /jorgen
Agreed and there is no correlation with acceleration or turning.
I don't know.
No points so I guess that means electronic ignition. Nothing too fancy.
It was certainly my first thought, but how could an exhaust problem be intermittent?
No, although I can't rev the engine with my head under the hood/bonnet.
I haven't pulled the plugs because I don't have the deep socket I would need, but they were changed 18k miles ago. No lack of power.
Thank you, Charles, for sticking with me on this.
I'll list my observations being as specific as I can. I know there's nothing like actually experiencing the problem first hand.
1995 900S, 2.3l non-turbo, 4 cyl., 113k miles. I've owned the car for all but 8k of those miles so I'm very familiar with the feel of it. Normally, it is smooth.
Went on a long trip (375 miles there, visited a few days, 375 miles home). Next time I drove the car (short trip to store evening of return) the extra vibration was present for the whole trip -- from starting of the engine to shut down both there and back.
Next day, no extra vibration at all.
Next day, extra vibration present for all driving that day.
Extra vibration gone for a while -- I thought (hoped) forever.
It progressed into an intermittent problem. Now it comes and goes during a trip -- perhaps several times or it might not happen at all or it might happen for the whole trip. These are just short, around-town, trips, 10-30 minutes.
Description of vibration: It feels and sounds a bit like a hole in the exhaust -- low pitch, feel it on the gear shift and gas pedal, don't feel it on the steering wheel. A passenger not touching anything might not notice it at all. An exhaust problem I would expect to vary in amplitude with engine throughput -- more gas, more vibration. This is
*not* what I observe. Vibration seems to be independent of engine throughput, only dependent on engine speed. It happens when the car is stationary and is exactly the same as when the car is moving. It seems to increase in amplitude as engine revs increase, up to about 3200 rpm where it either peaks or at least levels off.
The vibration is not random feeling. What I mean is that if the engine was misfiring randomly -- random sparks not occurring, say -- you would notice that randomness in the feel, it would feel jerky. That is not what happens. This vibration is very regular. It feels just like the normal engine vibration, but just at a greater amplitude. Does that make sense?
That's about the best I can do. If you think of anything let me know, but I may just have to see if it gets worse or hope I can demonstrate it to a mechanic. The local dealer is about 25 minutes away so by the time I get there it may not be happening any more. I'd hate to have to leave it with them for a few days for such a minor problem. The car is quite drivable after all. But I worry that the vibration is indicative of something potentially serious. Besides, it's just annoying!
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