Looking for some suggestions, this shaking/shuddering has got me stumped. This is a B18 swapped CRX with LS cable trans, new OEM axles, stage 5 sprung clutch.

During normal driving acceleration, as soon as I hit around 30mph, the whole car shakes until about 40mph. The severity of the shaking seems linked to the amount of throttle I give it, leading me to believe it's not a wheel or tire problem. Can feel in the steering wheel, seat, everywhere. I do not believe it is dependent on a specific gear, have felt it in 2nd, 3rd and 4th.

Axles were new, just installed by previous owner.

Next was motor mounts. They also look new, but I am not sure how to give them a thorough inspection. Do I need an engine hoist to dismount them and take a gander?

Please share any other ideas for what I should check next.

Thanks!

 

shaking the way your saying sounds like something is rubbing on the supports
take a good look around the engine bay and look for parts that might be rubbing somewhere

 

Thanks for the input. What supports are you referring to, the engine mounts?

 

these kinds of issues are more fundamental than a cursory check of the engine mounts looking new.

its typically a cracked subframe, or loose bolts. you need to inspect everything, every bolt.

the rear engine mount area is a common weak point and so is that sub frame in general. particularly with a swapped b series.

 

Binding inner CV joints can cause that. That could be caused by a bad CV joint or loose engine mounts letting the CV bind under accel.

 

Alright thanks. I will keep these ideas in mind.

Actually had someone make an offer for the car that I can't refuse, so I may not have to deal with it. They are aware of the issues.

Thanks!

 

First thing I would try is another set of wheels if they're available after inspecting all nuts/bolts for tightness.

 

Ok so it looks like I'll be hanging onto this car for a while, definitely want to get this fixed.

I will probably get the wheels checked but because it only seems to occur under acceleration, I am doubtful.

I have visually checked all areas around the 3 engine mounts and checked the bolts. I haven't found anything loose, cracked, otherwise not right. What is the next step?

I also wanted to note this car has a traction bar setup, and a solid front engine mount attached to the traction bar. This is to keep the turbo from rubbing thru the radiator. I expect this could cause issues and definitely stress the rubber mounts.

Any suggestions are appreciated.

 

Get an alignment, and get the wheels balanced.

 

My CRX is doing the same thing, I have a slight vibration during acceleration, esp in 3rd gear. I check all my bushings but everything is new. I think I have a slight alignment issue so i think I'll be trying that next. Let us know if you fix the issue.

 

I will try wheel balancing and then alignment next and let everyone know the results. May be a couple weeks. I will try to find a shop with a road force balancer if I can.


Bob1982,

Mine also does seem worse as soon as I hit 3rd. I think it's the combination of hitting the right speed and the added load on the chassis when going into the longer gear, or something. I'll let you know what I figure out.

 

I'm taking the wheels to get balanced tomorrow, and plan to check the alignment myself afterwards.

After raising the car to get all 4 wheels off, I spent at least an hour under the car, going over EVERYTHING. I checked every bolt I could find. Suspension, axles, brakes, mounts, steering rack, stuff that idk what it even was. Nothing loose, nothing out of place, nothing broken. If it's not the wheels or alignment at this point, I'm pretty stumped.

The only issues I did find, are that the bushings on the outer ends of the tie rods are gone, just grease everywhere and boots ripped up. There was no play in the rods though. Could this be part of my problem, and are they a pain to replace?





Also my lower ball joint boots are torn, but one was my fault when doing the axle. I plan to fill them with grease and seal the boots.

 

You can reboot the tie rod end if you know it's still good. But I'd do it before getting any alignment done.

 

One of the wheels was bent. I am betting this is 99% of my issue.

I had them switch the bent wheel to one of the rear tires (they are staggered 225 front 195 rear). And balanced them.

I also ordered new boots for the tie rods and ball joints, but that will probably be a project for another time. Wanna get it back together so I can drive it Monday and see if the vibration is gone.

Thanks for the suggestions

 

Issue is still not resolved.

Drove the car 22 miles to work today. Usually when it would start shaking under throttle I would back off and go easy until I was up to speed. Today I tried throttling through it and noticed there is definitely a lack of power, which has me wondering if it's not actually misfire.

Because I also had some other issues, where I'd be just cruising along when suddenly the wideband would read air, and it would start misfiring terribly. I know the car needs a retune, but this seems like an intermittent fueling or ignition issue. Which could also be the cause of the misfire/vibration.

So I am planning to start by checking the plugs, and getting the injectors cleaned. Any other ideas for what I should be checking?

Now I am just hoping I will make it home at the end of the day.

 

I got my injectors cleaned, put in new spark plugs, and checked my fuel pressure which ended up being good. I am doubting it is a misfiring issue, even though it does run a little bit lean under load (A/F ratio in the 15's) I am not sure this would cause the shaking. I will try adding some more fuel to the tune to get the AF where it should be.

Otherwise, I am still stumped on this issue. My alignment is good, wheels are balanced, axles are new (though I've only replaced the passenger side myself).

Could a bad bearing in the transmission or bad differential be causing this? Should I try replacing the driver's side axle, or is there a good way to diagnose if it is bad?

I'm tired of throwing different stuff at it to see what sticks. My mechanic thinks it is a bearing in the transmission, if not an axle. I have yet to take him along for a ride but will try to do so soon.

 

Got my fuel maps fixed, now it is running a little rich if anything. Still getting the vibration.

It's as if when I ease into the throttle, it doesn't get so bad and then goes away at higher RPM. But if I get on the throttle quickly where it starts to vibrate hard, it doesn't stop until I let off the throttle.

Any more ideas?

 

I am going to try to revive this, still having the issue. I thought it was resolved, but it is just an intermittent thing and I got my hopes up too high.

Here is what I have done so far:
- Replaced both axles
- Replaced transmission
- Torqued everything, engine mounts are good
- Balanced wheels and tires
- Ensured it was not a misfire issue (cleaned injectors, new plugs, adjusted tune, etc etc)
- New lower ball joints

I might try replacing the intermediate shaft, but I just don't think that is the problem. It only presents itself at about half throttle, after just shifting into 2nd, 3rd, and sometimes 4th gears. Once it starts to shake, it will not stop until I let off or go full throttle usually.

I am wondering about the clutch. Does this sound like it could be a warped clutch disc, flywheel, or that the clutch is getting contaminated with oil? The car does buck a little bit when taking off and slipping the clutch, but usually it's easy to avoid with proper throttling. The clutch holds fine when doing pulls in 3rd and 4th. But I know my rear main seal has developed a slight leak.

 

Keeping this updated in case anyone else comes along that has this issue. I've been searching and reading a lot of threads on different forums all the way back to 2000 with people having this problem. It always seems to be CRX or civics from the same model years with B series swaps.

I've done a bunch more work to try to resolve this. I may have finally made some progress today.

- New 86-89 axles, which are shorter than my other 90-93's to ensure they were not binding
- Had custom alignment done
- Replace rear lower shock bolts, one was broken
- New intermediate shaft

It was still shuddering as badly as ever. Only when I punch the gas, in 2nd or 3rd gear and sometimes 4th, between 30 and 45mph.

Then I noticed a loud creaking noise coming from the front right when I was turning, so I decided to investigate today. Turns out my two upper control arm bolts that attach it to the chassis were ever so slightly loose. When I yanked on it as hard as I could by hand, I could hear the creaking sound and it allowed the wheel hub to move very slightly. I tightened these up and the noise went away.

I only got to drive it a little afterwards, and I know the problem is not resolved entirely, but it does feel a bit better in 3rd gear. Need to do more driving for a thorough analysis.



Otherwise everything on the suspension is solid. Steering rack feels good, but I might replace it next year anyway due to it's age, along with the tie rods just to rule them out.

I have a new clutch and flywheel on the way, and picked up a rear main seal today. I may be doing this project very soon, to see if it could be a warped or contaminated clutch disc or flywheel. Sometimes the car does shake violently when taking off or when shifting if I let it slip. I thought this was normal from being a stage 5, but my mechanic drove it and said it didn't feel right. He suspected the clutch. It's worth a shot, and if it doesn't fix it at least I'll have a sweet clutch setup afterwards.

Stay tuned.

 

Thought I would bring this back up since I am still actively working to solve this issue. List of things I've replace as of today is below.

- New lower ball joints (checked all of them, the uppers and tie rod ends are good)
- New wheels and tires
- Alignment
- New Hasport engine mounts
- New clutch and flywheel
- New axles (on 4th set now, I don't think it's the axles).
- Checked everything in the suspension for play. Bushings, joints, steering rack, wheel hubs and bearings, everything is good and tight.
- And some other stuff

I am in the process of replacing much of the suspension currently, have new coilovers and new front LCA's on the way.

BUT the more I drive with this problem and think about it, the more it seems related to engine movement. At this point I should have very little engine movement, having stiffer Hasport mounts, and a solid front torque mount. However, when I take off from a standstill and slip the clutch, I get a lot of bucking like the engine is rocking back and forth quite a bit. I also still get this shaking when driving at part throttle in most of 2nd, 3rd, and 4th gear. I found a description that most accurately describes how it feels, as if I am "driving over rumble strips". The vibration coincides with the engine vibrations, except it shakes the steering and everything violently and gets worse the more throttle I give it, to a certain point. Then it smooths out above a certain RPM or speed.

I am leaning towards a cracked subframe. It just adds up and makes sense for everything I am experiencing with the car, with everything else I've eliminated as a potential cause.

My plan is to try to clean up the front sub frame the best I can, since it is covered in dirt and grease and whatnot, and try to look for cracks. It is going to be very difficult to see, especially from the top with the B18 crammed in there. But I want to be very thorough. If anyone has tips on checking the sub frame for cracking, I would be very appreciative to hear them!

 

Here is an issue I've had with my Civic subframe, the LCA's has a bolt that attaches to the subframe which has an internal welded nut. I had one of those nuts a few years ago break the weld from the inside. I have recently found this to be an issue now on my passenger side which now has play. When that internal nut breaks the weld it moves around and can start to loosen over time causing play in the LCA which could be an issue.

Not sure if this is something you have checked.

 

I put a pry bar in every joint and bushing and tried my best to find any weird movement. I couldn't find any so far, but if that is the issue then I will find that once I replace the LCA's. Thanks for the input!

I inspected the top of the subframe and rear engine mount area just now outside and could not find anything out of the ordinary. Will get under the car tomorrow and do a thorough run through.

One thing I've always thought was weird though, is all this seam-sealer or filler material in my engine bay. Is this normal? Looks like someone may have done some cutting and patching.







It's frustrating because I've come across tons of threads about similar issues spanning the past 15 years and most come to a dead end. Some are engine mounts or axles. Hopefully this one will come to some resolution eventually.

 

I can't confirm for sure if its normal but my 91 Civic has seem sealer in the same locations. From what I know my car was never in a front end accident so I believe it came stock with the sealer this way. I can try and post a pic of it later.

 

thats all stock from the factory.

hows your shocks? what springs are those?

blown shocks make the car do crazy juddery kind of driving with slight inputs of the wheel.