I've got a '99 Si that vibrates at highway speeds, but its at its worse around 70mph. I've put many new parts in it chasing the problem and not much has changed. I've ran it on jack stands and it seems to be associated with the wheel speed, not rpms. It also seems to shudder a bit when accelerating moderatly thru most gears.
I'm being breif with this post because of problems with this site(I wrote a huge post explaining everything and it was lost when I tried to send it, eeerrrrr!) But I would like to hear anyones input or ?'s that might shed some more light on the subject. Thanks

 

Shaking at constant freeway speed usually indicates that the wheels are out of balance.

Shaking while accelerating could mean the axles or motor mounts are bad.

 

Both axels are new and all the mounts are new except the tranny one that looks pretty good. I have all but eliminated it as a wheel problem, because I have had the wheels balanced and re-balance, rotated, I've even put a set of steelies on with normal profile tires that are balanced and it still is there, if not worse. Also I could feel it vibrating while spinning it on jack stands. That would eliminate the possibility that it is from one of the small bends in the wheel lip. I didn't see any vibration from the wheels or the engine while spinning it either, but I could feel it.
How often does an intermittant shaft go bad?
How much play should the shaft going into it have? Mine seems like it has a little more play than the ones on my Teg's, but it is almost brand new.
Are those little rubber balancers on the cv shaft vital? Cause the ones I got didn't have them on there.

 

Read this thread. Is the engine possibly misfiring?

 

It doesn't seem to be. It idles pretty smooth, once in a while it will idle high when I get off the freeway. But one good rev seems to cure that. Sometimes at start up it seems to run alittle rough, but once again alittle rev seems to smooth things out. Once running, especially on the highway I've never noticed any hesitation or bogging. It seems to be spot on with throttle inputs.
The car does burn some oil, about a quart every 1000-1200 miles. I've replaced the plugs with some good ones(not sure which) about a year ago or so. It has an AEM throttle body and fuel rail on it. But it just doesn't feel like a misfire. It feels like a vibration.

 

In a past incident, I had my wheels balanced but still felt vibration at freeway speed. I returned the car to the shop three times but they couldn't get it right. I finally took my car to a different shop that properly balanced my wheels and fixed the problem. Apparently the first shop did not have their balancing machine calibrated. They eventually refunded my money and also paid for the wheel balancing done at the second shop.

Many aftermarket axles don't come with rubber dampers like the Honda ones. The auto part stores claim that the damper is not really necessary if the axle is properly balanced. I was, however, able to order axles with dampers through O'Reilly. This may or may not reduce your vibration.

 

I have the identical problem on my jdm ef. Slight shudder under acceleration, followed by harsh vibration between 50-70mph. I have also had my wheels balanced over and over and tried different wheels/tires axles/alignment setups. I know my engine mounts r good cuz the car has 057,000kms on it. The problem never changes. I had a B16 swapped usdm ef that did the same thing for three years despite thousands in new parts. WTF?

 

Glad to hear I'm not alone with this problem. Maybe we can form a support group.lol.Well, if two of us have had the problem then maybe there are more. And maybe someone has figured it out... ...are you out there?

 

Any other thoughts or ideas...?

 

have you checked your wheel bearings

 

Replaced both within the last year. I removed the spindle myself and had a shop press in new ones. They said they both looked worn and I noticed they had a little play to them. but weren't too bad. I didn't notice much difference and it still has this rumbling,vibration.

 

I'm about to push this thing into the river....

 

have you tried to maybe switch the front to the rear and rears to the front? that may or maynot fix your problem.

 

I haven't switched front to rear, because one of the rear rims is kinda bent. But I have had the tires swithched front to rear and I've put a different set of rims/tires on the front. No change.

 

killer i had the same porblem on my ek4 after i got my big brake upgrade balanced at les schwab and drove it afterwards test drive butter!!!check that out balance the tires then get a allighnment ....butter!hope this helps.....

 

I do have aftermarket rotors on it, too. Do you think a rotor could be out of balance? I've pondered the idea, but I don't feel anything upon braking at all.
I got the car aligned only a few weeks ago, after replacing ball joints. It drives nice and straight, but I still got the shimmys.

 

I have the same problem, i have an ls/vtec swap in my 97ex coupe. Last time I got new tires they told me that I had a tear in the damper of one of my axles but didn't think much of that. but then yesterday i took a real sharp corner going fast and after that i'm now also getting the vibrations at highway speed between 65 - 70 mph, but that has now gotten even worse and I can literaly feel that its the front right wheel feels like its wobbling when i accelerate..taking her in for repairs tomorrow morning =( we should have a support grp..lol

 

I have the same problem with my car. I even changed the axles. I'm running out of ideas. It vibrates when I accelerate and at highway speeds. Thinking about buying hasport axles. Been using rebuilds from autozone because I have warranty for them.

 

well i just got back from the shop (since i don't really have any tools here and nothing i could possibly get underneath my car with..lol) and both my front axles are like..****ed lol..sleeves ripped off and really messed up..but getting them replaced and hopefully that does the trick and i don't do it again..isn't the wheel bearings they're in there like a glove idk..but we'll see in like 4 hrs lol..

 

have you noticed if the vibration differs when your accelerating vs highway speeds? you said you can spin your wheels while on jackstands and you can feel a vibration. are you sure the shop didn't mess up the bearings when they replaced them? it happens.

 

I have also sinned against the Honda gods and have used cv axel from Autozone. My friend works for Honda and he swears by only using genuine Honda parts, but I would be outta $$ if I lived by those rules.The Autozone ones don't have that little rubber "dampener" on them.
Is that soooo important? Do axels really come that unbalanced? Where does a guy go to get a shaft balanced?
I too liked the fact that I have a lifetime warranty on them, but is it a lifetime warranted piece of $hit?
In fact, working off the hunch that the new shaft was outta wack I pulled it out and exchanged it. The next one I got (for free atleast) felt the same way and didn't have the little dampener.
I notice that the drivers side cv that goes into the intermittant shaft(the one I have swapped twice now) has a bit of play in it. When you grab it, it can be moved enough that if it was outta balance it would have room to vibrate.
As far as the bearings, I would have to believe they were done properly. I had a shop do the pressing in and out, and I did the rest of the work. It is a good shop that has been around forever, and they only employ real mechanics. Not just a bunch of highschool, stoner, gearheads working for minimum wage.

 

next?

 

Thanks to everyone who has posted. Keep them coming...