Bad Vibrations…

[Frank F.]

My Daughter has a 2001 Honda Civic EX 1.7L V-tec (123,000 miles) that just recently started vibrating and shaking when at a stop light but only while in gear… as soon as you put car in neutral or park or pull away she is fine… any ideas what could cause the car to do this?? All major maintenance has been kept up and 2 vacuum lines replaced … Local yocal mechanic is stumped, he had the car for 2 weeks and has no clue what might cause this … I need some help in a major way.. thanks for any suggestions!

Topic

[Mikhail]

From my observation it looks like you have a motor mount gone bad… Check your RPM’s when it vibrates, where are they? They should be at about 750, anything lower and you may get vibration.

How is the car performing, is it firing on all cylinders?

[Daniel]

Be careful of neighborhood mechanics, they can often damage more than they fix. You are much better off going to a certified (and most importantly insured) mechanic. +1 on motor and/or trans mounts. Pop the hood have someone start it and then put it in gear, if the engine moves much when going into gear you probably have a bad mount. From the mileage you stated your probably about due for a mount to go out.

[Frank F.]

Thanks everyone.. Jus found out after a smoke test it was an EGR valve…. I hope this fixes it … It showed I had a vacuum leak and when we took out the EGR valve it was all black and nasty… We cleaned it as best we can and put it back in; it ran great for about 23 miles then at a light started shaking again so now I’m going to replace the EGR and how that fixes the problem. … Wish me luck! LoL

[college man]

keep us posted.

[EricTheCarGuy]

It’s not likely the EGR is the issue as EGR is only active under load NOT at idle. It will only effect the idle if it’s stuck open and you can check that easily enough by removing it and filling the valve area with solvent, if the solvent doesn’t’ leak out then the valve is good and not the problem. Additionally EGR does not use intake vacuum and it’s controlled by a solenoid on the firewall so a vacuum leak is not likely to cause your problem either. #1 thing I find with a situation like yours is when someone messes with the idle adjustment screw on the throttle body. For the rest I’ll post the ‘idle speech’ below.

By suggestion I’m going to post my idle speech along with a couple of video links that I hope will help if your having problems with your Honda’s idle.  First I’ll give you the link to the Solving Honda Idle Problems video, please remember that adjusting the FITV is the LAST step in the process and you need to back it off at least 1/2 turn after it bottoms out or it will not start properly when cold.

The Bleeding a Cooling System Video

The video response to the Honda Idle video

http://www.youtube.com/watch?v=AMjQry8mz-E&feature=watch_response

Lastly here is the “Idle Speech”

There are a lot of things that can contribute to an idle issue, in fact in the end it may still be there to some degree because of the nature of a 4 cylinder engine however here are some things to start with.

First start with a good tune up, use NGK or Nippon Denso plugs, don’t change the wires if they are OE, if they aren’t OE you might consider NGK wires as they are very good and less expensive then OE.  A quality cap and rotor should be good.  A new air filter also helps.

Don’t change the PCV valve, if you see an aftermarket PCV valve in there put a Honda in, believe it or not I’ve seen idle issues caused by aftermarket PCV valves, the OE’s last just about forever so you can easily justify the expense.

Next a good valve adjustment, this goes a long way to smooth out the idle if done correctly, mess it up and things can get a lot worse though.

While you have the valve cover off check the timing belt tension, if you feel a lot of slack this can cause the cam to ‘chunk’ as it spins causing a rough idle.  If you think the belt has been on there for some time then you might consider changing it and resetting the tension properly, if it’s not ready for replacement you can reset the tension to take up the slack.

DO NOT adjust the idle screw under any circumstances, it is set at the factory and that is the reason it was sealed in the first place.  If you find that the seal has been broken and you have a low idle and you have done all of the above then you might turn the screw out a little to see if that helps the idle but only enough to try and bring it back to where it was before it was adjusted in the first place.

Last clean the screen in the Idle Air Control valve, this can get clogged up with carbon over time and cause the flow through it to be restricted which can cause idle issues.

If you still have a ‘rough’ idle after all of this THEN look to the engine mounts as you want to be sure the engine is running correctly before you go for those as the one in the back is a real pain to replace.

I hope this info is helpful as I get a TON of questions about Honda idle problems, thanks for reading.

[Author]

Replies