Wierd Vibrations......

[TsubohachiLX-i]

Hello 3GEEZ!!!

Its been a while since I've been in, as I've been doing a lot of BUYING and COLLECTING parts for this summer's UPGRADE SESSION.

So far, I have one problem that has been aching me:

Whenever I run my LX-i in the DAYTIME (going to work, school, store, etc.), there is a moderate amount of vibration whenever I'm at a red light. But when I run my LX-i at NIGHTTIME, there is even more vibration when at the red light. The main thing that I've noticed is that the TIME OF DAY affects the vibration (with MORE vibration occuring at night), as the idle is LOWER when at a red light at night. I also notice that the vibrations don't start until my LX-i reaches normal temperature, and only occurs while in D or R while holding the brake.

I have a few hunches, but I was wanting to get your hypothesis on this ordeal first...

[A18A]

put it in neutral at the lights :thumbup:

[CzEcHy]

Motor mounts, Honda OEM ones (expensive but they will work properly)

[redaccordcoupe]

I agree motor and tranny mounts will do that. Wish they made urethane ones for us. And its probably more at night because during the day the rubber in the mount expands with the heat. And at night its probably contracting causing play in the mount. Check the bolts to see if any have vibrated out. I got my 3g with 265k and under the hood lots of things were loose.

[ecogabriel]

Hello 3GEEZ!!!

Its been a while since I've been in, as I've been doing a lot of BUYING and COLLECTING parts for this summer's UPGRADE SESSION.

So far, I have one problem that has been aching me:

Whenever I run my LX-i in the DAYTIME (going to work, school, store, etc.), there is a moderate amount of vibration whenever I'm at a red light. But when I run my LX-i at NIGHTTIME, there is even more vibration when at the red light. The main thing that I've noticed is that the TIME OF DAY affects the vibration (with MORE vibration occuring at night), as the idle is LOWER when at a red light at night. I also notice that the vibrations don't start until my LX-i reaches normal temperature, and only occurs while in D or R while holding the brake.

I have a few hunches, but I was wanting to get your hypothesis on this ordeal first...

I will leave aside the issue of motor mounts and instead focus on the transmission.
The vibration you feel is there all the time the car is in D or R; is it there if you shift the transmission to say D3 or 2? I have to assume that you do not feel the vibration (or at least not as badly) when the car is either in P or N.

If your car vibrates badly whenever it is in gear and assuming the mounts are OK) that your car most likely has a problem with the torque converter. I heard about it here; my car vibrated like breaking one's teeth whenever it was in gear.

No other problems with the transmission it shifted right and no other problems. I was hunting for a new torque converter when I found a used serviced transmission in local craigslist (I ended up with mushroomtoy's transmission) and not more vibration -no more teeth grinding. Check the service manual in the transmission part; it suggests a couple of things to do and the possible causes for the vibration. There is even a bulletin about it; someone sent it to me a while ago but I can't recall where I saved it

[TsubohachiLX-i]

I had the FRONT and REAR motor mounts replaced around April of last year, with the exception of the TORQUE STRUT MOUNT and DRIVER SIDE MOTOR MOUNT. I used the ANCHOR and WESTAR brands, although I've heard the Honda ones are better.

Would it help if I changed the VIBRATION DAMPER?

As for the Transmission, that was also rebuilt around the same time of the mount replacements, so I don't know if that could be the culprit. I will go out tonight and test the D3 and 2 gears to see if there's vibration there, and I'll also check for loose bolts.

I didn't know there was a tranny mount; I thought the engine supported the tranny...

[ecogabriel]

I had the FRONT and REAR motor mounts replaced around April of last year, with the exception of the TORQUE STRUT MOUNT and DRIVER SIDE MOTOR MOUNT. I used the ANCHOR and WESTAR brands, although I've heard the Honda ones are better.

Would it help if I changed the VIBRATION DAMPER?

As for the Transmission, that was also rebuilt around the same time of the mount replacements, so I don't know if that could be the culprit. I will go out tonight and test the D3 and 2 gears to see if there's vibration there, and I'll also check for loose bolts.

I didn't know there was a tranny mount; I thought the engine supported the tranny...

There is a small mount that bolts to the crossmember and goes in an opening in the transmission; ideally it should sit between the opening ends. Some cars have also another small mount on the right end of the transmission.

If the torque converter was replaced when the rebuilt was made, then I think more on mounts. More specifically, I found the engine a f... bitch to center in the engine bay without being suspended (the way the tightening engine mount sequence is set up in the manual) Maybe I'm stupid :banghead: or I missed something.
I noticed that the mount that bolts where the timing belt cover is breaks easily unless the engine is more or less centered in the engine bay... if that one is broken (driver side engine mount? is that the name?) you will get engine vibration.

[Dr_Snooz]

I would just kick up the idle speed a teensy bit and call it done. I've learned to ignore the manual when it comes to setting the idle speed. You should set it where there is the least vibration.

[CzEcHy]

ANCHOR mounts - crap.



Also, if you raise your idle do it a small tad like snooz said, above 1000 in D will kill your brakes faster cause the added strain it's holding back cause the engine wants to go.


But cruising through a parking lot with your foot off the gas is alot funner since the car keeps cruising at 1000 rpm

[TsubohachiLX-i]

I checked the D3 and 2 gears last night and found that the vibration is still there, STRONGER in D3 and WEAKER in 2. Everything feels normal and smooth while I'm driving, and the tranny shifts at the correct ratios, its just when I'm sitting at a red light when the vibrations start. I'll check the tranny fluid to make sure its full since I forgot yesterday...

All the mount bolts are torqued pretty tight, although I need more time to check for any other loose bolts such as in the suspension. Can someone post a picture or diagram of the tranny mount so I'll know how to find it?

Anyway, here were MY suspicions:

*Old Cat Converter

*Old Fuel Injectors

*Something in the Ignition

*Driver Side Fender Wires from last years' Tire Blow-Out

*Possible Timing Jump

I'm not going to adjust the Idle Speed right now, because that only hides the REAL problem, its doesn't neccessarily fixes it...

[Dr_Snooz]

Rough idles can be caused by a lot of things:

- dirty fuel system
- malfunctioning EGR
- vacuum leak
- idle speed set too low

I'd start with a vacuum gauge test, a can of Techron or equivalent and a look at the idle speed. What is your idle speed set at anyway? I think 750 is too low, but maybe not if you have an AT. The bottom line is that you can spend a lot of time and money trying to track it down and never really figure it out. If you're not being consistent with your maintenance or are using poor fluids and filters then that's the place to start. Is this a really bad vibration or just something slightly worse than normal that you'd like to make perfect? (I tend to fixate on the slightly-less-than-perfect too so I'm not judging)

[TsubohachiLX-i]

Well, at nighttime I guess you can say its irritating, as opposed to the daytime being somewhat tolerable. I just want the vibrations either completely gone or brought down to a minimum, so perfection is something I'm not asking for.

And I keep up with all maintenance intervals, so I guessing it may be something defective or an old part thats about to give out. I just named off the parts that I haven't tackled yet that have a lot to do with Idle.

[car6289]

Try driving during the day with your headlights on, it sounds like you don't. Does your vibration stay somewhat tolerable or become irritating while stopped? If it becomes irritating, I'd bump up the idle rpm slightly. The increase in electrical load with lights on has subtle downward effect on idle rpm, most noticeable when stopped, brake lights, a little more current draw, a little more rpm drop. Each auto tranny 3G has it's own happy idle speed, where idle vibration is at a minimum, daytime or night, lights on or off. The manual spec idle rpm is the perfect world, perfect car scenario. The world isn't perfect and neither are our cars. The cars are very close though.
As A18A suggested, shift to "N" when stopped at night, not a fix but a viable interim solution.

[dreeeemA]

I have had the same vibration in this motor. What can happen is the right lower motor mount collapses. This hard to determine as it will not look broken or anything else, but the rubber inside it was not hard enough and it sags and acts like the motor is grounded out.

[Dr_Snooz]

Clean your IACV. Also, did you torque your motor mounts in the proper sequence and to the right spec when you replaced them? If you didn't that can cause vibration too. At least, that's what the manual says...