I've got quite a vibration at idle while in gear (automatic trans). Not like a misfire/rough running sort of thing but just a plain old vibration. In neutral or off-idle it goes away.

My first thought is motor/trans mounts although I have not even looked at them yet. Do you think I'm on the right track? Any other likely faults?

Be gentle...I'm new to Japanese cars :-)

Thanks
Doug Dwyer

 

Yes, you are on the right track. Inspect the mounts.

 

I was just about to post about this exact thing. My girlfriend's '93 accord has the same problem. It's an automatic, and its only when in drive when I'm stopped at a light of anything else of that nature. I just noticed it tonight very slightly even when in park. In addition, (this sounds crazy but...) but the vibration gets a little worse if I turn the headlights on, then if I turn them off, it settles down a tad. That boggled me...

So ditto, what is this? If its motor mounts...is the vibration caused from the torque of remaining idle, and no movement?

 

my 93 does this also is there a certain way to check the mounts without just looking at them?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeeDiggs &raquo;</TD></TR><TR><TD CLASS="quote">I was just about to post about this exact thing. My girlfriend's '93 accord has the same problem. It's an automatic, and its only when in drive when I'm stopped at a light of anything else of that nature. I just noticed it tonight very slightly even when in park. In addition, (this sounds crazy but...) but the vibration gets a little worse if I turn the headlights on, then if I turn them off, it settles down a tad. That boggled me...

So ditto, what is this? If its motor mounts...is the vibration caused from the torque of remaining idle, and no movement?</TD></TR></TABLE>


Try adjusting the idle with the little screw on top of the TB. Loosen it to raise the idle up a bit, it should smooth it out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DougD &raquo;</TD></TR><TR><TD CLASS="quote">I've got quite a vibration at idle while in gear (automatic trans). Not like a misfire/rough running sort of thing but just a plain old vibration. In neutral or off-idle it goes away. My first thought is motor/trans mounts although I have not even looked at them yet. Do you think I'm on the right track? Any other likely faults?
Thanks
Doug Dwyer</TD></TR></TABLE>
When the engine vibrates, does the idle rpm also drop? If so your problem could be related to the IACV or the base idle speed being too low. The IACV adjusts idle speed when the engine is under an auxilliary load, such as when the transmission is in a gear (a load through the torque converter), air con is used, lights, window winders etc etc. The base idle is the idle speed with the IACV not operating and no auxilliary loads. You can disable the IACV by disconnecting the electrical connector at the IACV, or by shorting the 'diagnostic' connector (under the dash somewhere).

If the base idle speed is too low then when an auxilliary load is placed on the engine the IACV may not be able to adjust the idle speed enough, but this is likely only in the case of the IACV being partially blocked.

First step would be adjust base idle to spec, then if the problem persists cleaning the IACV internally.

 

Thanks for the reply.

No, the idle speed is steady and does not drop, but I have not checked (or even noticed) if it is too low. Good idea, thanks.

I did find that the front engine mount is broken. I'll be replacing it in the next day or two. We'll see what happens. I can hardly even see the other three mounts, much less ascertain their condition.

Thanks
Doug

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by johnlear &raquo;</TD></TR><TR><TD CLASS="quote">First step would be adjust base idle to spec, then if the problem persists cleaning the IACV internally. </TD></TR></TABLE>

Just to clarify that Your first step should never be to just adjust the factory set idle speed screw. There is a proper way to adjsut your base idle. If your idle starts to become erratic, low or high it's usually not the base idle or idle speed screw that need to be adjusted. Depending on the situation it could be a vacuum leak, low coolant level a non functioning IACV, FIT or a clogged IACV or dirty throttle body.


To the OP check your mounts for cracks as stated above

and to the other idling problem posters maybe try cleaning your IACV and EGR ports to get your idle back up. There is a write up in the FAQ's on how to properly clean your IACV and adjust the base idle afterwards if need be.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GhostAccord &raquo;</TD></TR><TR><TD CLASS="quote">

Just to clarify that Your first step should never be to just adjust the factory set idle speed screw. There is a proper way to adjsut your base idle. If your idle starts to become erratic, low or high it's usually not the base idle or idle speed screw that need to be adjusted. Depending on the situation it could be a vacuum leak, low coolant level a non functioning IACV, FIT or a clogged IACV or dirty throttle body.</TD></TR></TABLE>


I've always treated the idle screw as a fine tuner

Which loosening it up a few turns can drastically smooth out your idle.

 

Yeah it's good for doing that when your car is running properly. I used to do the same thing to fine tune my base idle from winter RPM to summer RPM. I always had my base idle a wee bit higher in the winter time. But when you have an idle problem I don't shoot strait for the idle screw as it will only mask a possibly bigger problem.

Just for an example. I had a local kid come to me that said he couldn't get his idle adjusted and his car was idling badly. I showed him how to clean the IACV and off he went. Next day he came to me and said when he reset the ECU and started the car his base idle was up over 2500. Why ..because he had his idle speed screw backed out as far as it would go. Obviously he had been doing this for a while and it hid the fact that his IACV wasn't workign properly. Blahhh Blahhh Blahhh....

 

Definitely go full-boat and pull off your throttle body in addition to cleaning your IACV. I just did that job and it made a world of difference! My IACV was pretty dirty, but after pulling my throttle body I found that I actually had a big carbon turd in my idle air screw's passageway, which explained why I had a shaky idle that I could make go away by just barely touching the throttle.
If you haven't already, pull your plugs and look for oil on them. My lower rocker arm oil seals were blown and leaking all over my spark plugs, which may make for poor idling as well. That job looks daunting at first but it's really pretty easy if you're careful (if you need to do that job, PROTIP: you do not need to remove the timing belt nor do you need to back off the valve lash adjusting screws, contrary to the CB7Tuner walkthrough's initial steps)

With regards to the EGR ports, be careful when reassembling the fuel rail and injectors, i.e. cycle your fuel pump by going in between ACC and ON a few times to build up pressure. I forgot to do this and didn't catch an injector-to-rail seal that had torn slightly and started spraying gas all over my engine!

 

Doug.
I had the same problem with my 94 Accord Wagon. It has A/T also.
I found the problem to be the nylon bearing on the vacuum actuated lever arm of the rear engine mount. The bearing had worn out and the lever arm had popped out of the operating lever of the hydraulic mount leaving it in the "Hard" position.
When operating correctly, this vacuum controlled arm moves the lever to allow hydraulic fluid to transfer from 1 chamber in the mount to the the other chamber hence "Hard" and "Soft" settings. The "Soft" setting is used for idle speed below about 1000 RPM where the engine can move about and the vibration is damped.
The "Hard" setting is used above 1000 RPM and the mount is locked.
The nylon bearing would only cost about 10 cents but I don't think it is a spare part item from Honda.
You have to buy a complete mount or do as I did and get one from a wrecked car and just replace the vacuum unit if it has a good bearing.
This can be done, by feel, from the top by reaching down behind the throttle body to get at the mount. There is just a sliding clip holding the vacuum unit to the mount.
I hope this helps.

Regards,
Larry