91 Lx With Strong Vibrations???

[likeabuh]

this is gonna be kinda long but i gotta tell the whole back story too...

for the last three or four months (basically since it got cold in va) ill be driving my car, and about 15 minutes into the drive....my car will start to rumble like it has a flat tire...the first time it happen i checked to make sure there wasnt any broken suspension parts...or flat tires lol
it always happen in 5th gear at about 50-55 mph. after the first couple times it happen i found i could push in the clutch, and let it back out quickly and the problem would go away. about a month ago that stopped working, i started having to slow down to 20 mph, drop it into 2nd, and run every gear up over 3500 rpms so by the time i was in 5th it would be gone...

i tried to figure out what it was, but it happen so irregularly that i never could reproduce it while i wasnt doing anything...i kinda blew it off because it really only happen on the way to work at 3 am and this car kinda has a mind of its own and really does what it wants to do...

thursday before christmas, it snowed here...and somebody rear ended me, and pushed me into the gaurd rail. it wasnt any mechanical damage (that i could see) all cosmetic, no wobble, no hard pull...nothing...

friday that just passed i got all new tires put on the car, but it was at a used tire place so they used for floor jacks to jack the car up, and i really cant remember exactly where they jacked the car up but i usually i watch them like a hawk after i had to stop going to another tire place because they wouldnt stop jackin my other car up by the oilpan...but i know the car was off the ground completely (for the first time since the accident)

sunday,my car started running ROUGH, i was driving along when i started to feel a familiar rumble...so i slowed down and ran it back up, but it didnt stop. and it did something different, normally if i back off the gas, it stops but this time when i backed off the gas it made a completely different noise...going up in rpms, it sounds like a flat tire, going down in rpms it sounds like spun crankshaft bearings....

so my initial thought was that the timing belt had jumped or that the injectors were bad...and asking my friend he said he had somewhat of the same problem right before his timing belt broke on his 91...but on my way home from work today i finally was able to really listen and try some other things...

the first is, i have NO loss of power...i mean none...it still pulls just as hard, and runs up just as fast as the day i bought it...and revving it while under the hood,i only hear the faint beginnings of valve tap on the cylinder closest to the pulleys and i know the valve cover gasket (and the spark plug gaskets?) are leaking on the other side but its comming up on 180k...i run midgrade because i did it to see if it made a difference in the summer, and it made a tremendous differnece,so thats what i usually run, but i filled up on regular this past friday

second, the car ONLY makes the sounds and heavy vibrations while moving, if im in neutral or have the clutch in it doesnt vibrate, but i can still hear the sound like a bearing....but it matches the speed of the tires, not the speed of the engine...then as soon as im off the clutch its all back...and it doesnt really matter how fast im going or how high the rpms are until the clutch is fully let out

the idle isnt rough but there is a steady vibration

i bought the car with a dying throw out/release bearing and i also think the input shaft bearing is going bad

i really need help, because my job always has me on crazy hours so having a weekend to mindlessly work on the car is out of the question i need some help pointing me in the right direction, because tax time can either go to fixing evrything wrong, or investing in another....sorry for the long post

[SOHC-FTW]

Sounds like the throw out bearing to me.But have you checked the mounts out?

[likeabuh]

...i was thinking it was the bearing but my problem is no one i know can tell me exactly what happens when it completely fails....is it just noises....does it not disconnect the clutch plate anymore....does it make the car violently shake....does it make the car completely undriveable.....


because its been bad, and my clutch doesnt hook up until the last few millimeters of the pedal travel...and it usually drops hard...or if it does start to let out smooth, it gets jumpy...like the entire car starts to jump....not like stalling, more like going over a bumpy road



i just checked the front mount, and it does look like the rubber is torn, and the torn part is sitting about 1 inch lower than it was suppose to...where exactly are the others because if i have to go under to see them, ill have to wait till im at home with my jack

[stunin92_accord]

vibration reply

sounds like your rear engine mount is bad and push bearing is bad..if your push bearings fails,..it wont have that enuf force to put pressure on the pressure plate..it could be drivable but it will perform bad.

[kellogg_racing_]

As already said, sounds like possibly a rear mount. I'm not repeating information, just adding information: keep in mind that its vacuum controlled, so it is POSSIBLE something could be triggering an off vacuum that causes the vibration (since it only happens at high speeds, ie: a certain manifold pressure) and if the rear mount is bad, that would just multiply the feeling. Is the car rocking/bucking back and forth? My bud's motor mounts are horrible and when you get to a certain speed and clutch travel, it does that. That similar feeling to what you described is what has me thinking it could be a motor mount, and since it only happens at a certain speed, maybe the rear (or a combination of all; is the rubber surrounding the mounts cracked or look deteriorated?). Anyways, I had to replace my mounts at about 140k, so even if it turns out this isn't it, there's no harm in replacing them as they're probably worn anyways.

hope this helps!