Hi,

I have a 99 accord that I recently bought and under acceleration it is kind of rough and loud with some vibaqration. At idle or when I let off the gas it is smooth and quiet. Under acceleration OR just maintaining speed on the freeway I get a growling/rough noise and some high frequency vibaration in the car and steering wheel itself.

I don't know much about Honda vehicles, but it is a 4 cil, ULEV V-tec according to the top of the engine.

It has 190,000 miles on it.

What do you think this could be? Could you also let me know how to check to see if the problem may be what you recommend so I can get back to you ASAP?

Thank you everyone!

 

Is it the kind of growl that might be an exhaust leak, or even the exhaust flexing as the engine twists in it's mounts?

How about engine mounts going bad? That can give vibration only under acceleration.

Bad inboard CV joints on the drive axles can give vibrations under acceleration only, but usually described as something similar to a wheel-balance thing.

Any of those ideas sound like they might make sense?

 

Good call... an exhaust leak or motor mount may be the issue here.

2 questions:

What is the best way to check these items and determine if they need to be replaced?

How many motor mounts are there and are they difficult to change?

 

Can you crawl under the car? If you have to lift it, make sure it's real solid so it doesn't fall.

Grab the exhaust & try to move it around. It's supposed to move, all the hangers are rubber. But you're trying to find out if you can easily get it to bang against the underside of the car.

Get a helper & start the engine & let it idle. Push a wadded-up rag against the tailpipe, to obstruct the exhaust. Not enough to stall the engine, just enough so any exhaust leak will get louder. While holding that, listen around the engine comparment & underneath the front of the car.

I think there's 4 mounts, one front & center, one at each side of the engine/transmission assembly, and one buried low in back. The one in back is a pain. Grab the valve cover & shake it around. Any of the mounts seem excessively loose or make a klunking sound?

 

Awesome! Seems pretty easy to check all this stuff I will give these things a try when I get home from work.

I really appreciate it! I'll give you an update when I get done.

 

you would hear an exhaust leak... it results in a louder exhaust under acceleration.

normally with bad motor mounts, you can easily check and see if there cracked from looking down in the engine bay.

other vibration issues are normally caused the timing whether its the plugs/wires or even your valve timing

** its a 99 ulev? i am curious if you have ever replaced the o2 or exhaust? the ulev f23a4 compared to the f23a1 has diff plugs/exhaust. Having the " cheaper " version of the o2 sensor will not draw a code but will result in the engine trying to compensate.

*also, if you have had a new exhaust put in place, if they welded it to the frame, perhaps you are feeling the vibration from that? if they used J hooks, then the vibs should be cut down to minimal

 

Good morning, I have actually not yet had a chance to check the motor mounts, but I will ASAP. I will probably have some time later today to check for this. This is the 1st thing that I am going to check.

How do I check the timing or valve timing? That is something that I can check off the list when doing the diagnosis.

It is a ULEV and I do not know if the o2 or exhaust have ever been replaced. I bought the car only a few days ago and it has 190K miles on it. The dealer said he just did a tune up, but there is no verifying that. How do I check for this issue and verify weather f23a4 or f23a1.

I will probably have to get ramps to be able to get underneath and see if the exhaust is welded to the frame. I won't be able to do that until this weekend. I'll let you know if I see anything after I check this. Who is their right mind would weld exhaust to a frame? LOL

 

Does ANYBODY weld exhaust directly to the frame?? Well, lets hope you don't find it that way.

I thought that the wrong O2 sensor in a ULEV car would throw a check-engine light, but I didn't own a ULEV so I'm not completely sure about that.

Camshaft timing is easier to check, but balance-shaft timing is the one thing that can cause vibration. But I think it would be all the time, not just under acceleration.

Only bought the car a few days ago? From a Honda dealer? See whether he has any record of the timing belt being replaced. It's due every 100k miles or 7 years, so it had better have been replaced before. If it was done at a dealer there might be a record.

 

It runs smooth at idle and just is kind of loud and the high frequency vibaration on the steering wheel and rear view mirror under any amount of power applied to the gas.

It was not a honda dealer it was a small dealer. I saw the records of what he did to the vehicle so I will ask him when I go back there. I have to go back on Saturday because he is replacing a piece in the passanger door to allow it to open from the inside.

If I have no idea weather the timing belt has been replaced should I do it myself and is it fairly simple? I have a timing light that my dad gave me years ago, but I have never done timing myself.

 

Timing light is for spark timing, not camshaft timing.
Changing the timing belts is a big job, so I guess the question is what kind of big maintenance jobs have you done in the past?