vibration at idle

When I am at a stop light my 95 accord F22b1 will have a vibration, or shake to it. Kinda like I have a vibrating chair or something.

I have a new timing belt, dis cap, rotor, plugs, wires, EGR valve, EGR ports cleaned, used SeaFoam, PCV valve, fuel filter, and oil change. What else could it be, or should I try? Thanks guys.

Motor mounts. Pretty much guaranteed.

This might be a dumb question, but where are my motor mounts and how do I check to see if they are bad? Thanks again, :)

Well, they are kind-of obvious, but you can't easily check them. How many miles since they were last replaced? The one that causes the vibration is on the left side of the motor (which means nearest to the firewall). It's also by far the most expensive (and we aren't talking about 30 bucks here). 2 types - for manual and auto. Get all of them replaced, though you might want to go after-market for at least the pricey one.

Thanks again. I don't know if they have ever been replaced. Is it something I can do myself?

I'd see if the mixture screw on the throttle plate is accessable before buying an expensive mount. If the mount was bad, you'd most likely have other issues (distinct clunk when transitioning from power to coast, slight highway speed driveline shudder, etc) Just about every Honda I ever had come through the shop that was more than 5 years or so old would vibe at idle in gear, especially with the A/C on, and a slight (1/2 turn or so) adjustment of the idle mix screw would have it idling smooth again.

Be prepared for codger to call me a heretic, for some reason he refuses to acknowlege this well known quirk of Honda motors....

I'd see if the mixture screw on the throttle plate is accessable before buying an expensive mount. If the mount was bad, you'd most likely have other issues (distinct clunk when transitioning from power to coast, slight highway speed driveline shudder, etc) Just about every Honda I ever had come through the shop that was more than 5 years or so old would vibe at idle in gear, especially with the A/C on, and a slight (1/2 turn or so) adjustment of the idle mix screw would have it idling smooth again.

Be prepared for codger to call me a heretic, for some reason he refuses to acknowlege this well known quirk of Honda motors....
thanks for this information, do you have, or know where I can find, a picture of this? I am not too familiar with the idle mix screw and its location.

thanks for this information, do you have, or know where I can find, a picture of this? I am not too familiar with the idle mix screw and its location.

http://images5.theimagehosting.com/wscrew.jpg (http://www.theimagehosting.com)

This is supposed to be a '94-'97 Accord throttle body. You are looking into the end where the duct from the air filter box comes into it. I outlined the adjuster screw. In your case, you probably want to go out (counter-clockwise) a bit and see if it helps. Remember how it was positioned before you started, and count the turns as you do it. That way tou can return it to where it was if it has no effect. You shouldn't have to go more than 2 full turns, if so, you have other issues. (sucking air or carboned cylinders, etc)

When you feel it beginning to smooth out, continue to turn in that direction until it no longer improves. Then go back about 1/4 turn. That should be about right. It helps if you have someone hold it in gear while you do it, so you can really feel what the motor is doing. Having the A/C on will load it up and make it more obvious too.

Might wanna blast that puppy with some spray throttle plate cleaner while you're at it...deposits will sometimes cause the plate to stick slightly open at idle, which is similar in effect to a large vacuum leak (jittery idle and cold start stalling when put in gear)

Thanks very much for your help, I will check it out this weekend! :)

The thing I'd ding you on, Jeffcoslacker, is the statement that bad motor mounts would show up as other problems. I've had motor mount problems in 3 (similarly old) Accords, and vibration when idling (especially with the AC on) was the ONLY symptom. (But the vibration was pretty bad).

Adjusting the idle? Well, sure - on a 1981 Ford truck. But an ECU-controlled 1995 Accord? I hardly think that's the way to go. He didn't even tell us his RPMs at idle. If they are around 800 (in drive, AC on), then that doesn't need adjustment. "Well-known quirk?" Well-known to whom? Not the Honda mechanics I've spoken to.

My idle is right at 760 when I am parked and in drive. As the car is vibrating, the rpm tach doesn't even move, or if it does you really have to look at the tack to spot it.

The thing I'd ding you on, Jeffcoslacker, is the statement that bad motor mounts would show up as other problems. I've had motor mount problems in 3 (similarly old) Accords, and vibration when idling (especially with the AC on) was the ONLY symptom. (But the vibration was pretty bad).

Adjusting the idle? Well, sure - on a 1981 Ford truck. But an ECU-controlled 1995 Accord? I hardly think that's the way to go. He didn't even tell us his RPMs at idle. If they are around 800 (in drive, AC on), then that doesn't need adjustment. "Well-known quirk?" Well-known to whom? Not the Honda mechanics I've spoken to.

Not the idle, codger, the idle mixture. There's a difference. And the ECU can deal with the parameter change, it's within it's programmed map, or there wouldn't be a provision for adjusting it.

Idle MIXTURE, I keep telling you.:banghead: The idle adjustment is a lockscrew on the throttle bellcrank stop.

Are you sure they didn't sell you an expensive mount because you didn't know any better, and then adjust the mixture while they were at it to cure the problem? :lol: That sounds like a typical dealer hose-job...

I'm just teasing you codger...I know you know a lot more specific info about these cars than I do, but I've done this so many times on so many Accords over the last 10 years as they came through the shop, I find it hard to believe I'm not onto something.

The high price of that mount makes me believe it is a liquid-filled design, right? Those are specifically engineered to quell the odd vibes that four cylinder motors without balance shafts are known for. In that case it would be considered a damper as well, and I could see where it would transmit a lot of primary vibration to the chassis at idle if it failed, you're right.

My biggest fault as a mechanic is my honesty. I'd have people with these cars come to the shop with this symptom, prepared to spend a lot of money to correct it, and when I'd go out there and cure it with a 3/4 turn of a screw and tell them no charge....you just knew they'd be back for any repairs from then on.

I wondered at one time if this adjustment had any negative effect on idle emissions, as at the time that's how we were testing, using BAR 90 protocol, but after some experimenting with cars that were there for low emissions tune ups to pass the test, I found that the adjustment always brought HC levels down, and of course has no effect on off-idle emissions, because idle mixture is not a factor once the throttle plate is opened.

If I'd thought I could sell a $500 motor mount job with a clear conscience every time one of those came in with that complaint, I would have done it.

My guess is that we are probably both right.

Here is my theory:

A liquid filled mount/damper works kind of like a shock absorber, in that it allows the movement, but resists it by forcing the movement to push viscous fluid through a valving system that only allows a predetermined flow rate. So as it moves one way, it is softened and slowed down, then as it moves back the other way the amplitude is shorter (because it was damped) and the fluid is pulled back the other direction, damping that motion as well, etc, back and forth as the motor (or car body) rocks.

Just as with shock absorbers, liquid filled mounts will become less effective over time as they wear, long before actually failing. All motors loose some idle efficiency as they age, due to combustion/valve deposits, intake varnishing, spark plug gap wear, timing chain/belt wear, tiny vacuum leaks, etc. It's a very slow process, but it happens. At some point, you need to adjust the mixture slightly to correct it. On motors with full computer control over idle mixture, there is no provision to do so. Older Accords are not that way. It can compensate to some degree by varying fuel injection strategy based on what the o2 sensor is telling the computer, but as long as the o2 sensor reading satisfies the ECU, that's all you get. It has nothing to do with actual idle stability.

So my guess is that at a certain point, the degradation of damping ability and idle stability meet, and the driver experiences the vibey in-gear idle that Accords and some others are notorious for. Seemed to me that most people found it unbearable when they started using the A/C for the first time in the season, and would make comments like "I noticed it a little last year, but now it's driving me crazy...".

And chances are that adjusting mixture to create a more stable idle, or replacing the less than perfect damper are both ways to correct it. Except one takes two minutes and costs nothing, the other puts a huge dent in your wallet. Faced with that choice, which one do you think the dealer recommends?

Also, not to slam dealers, the facory, by the book repair procedures that dealers follow do not EVER include adjustments where replacement would correct it. That even follows into the body shop, a dealer body shop will never repair anything that can be replaced. So they are obviously the best place to get estimates:iceslolan

Their repair procedures have a few basic ideas in mind, and they are not totally evil when viewed objectively. They are there to make money. They are there to sell OEM parts. They want the least liabilty. So the tendency is to "overfix" to cover all bases. You will never catch a dealer putting new bearings in a bottom end when they could be installing a short block, that kind of thing...

But ultimately, you are probably correct, that the permanent fix would be to raplace the damper. But bear in mind that a vibey motor is going to wear that one out quicker too. For myself, I would see if it adjusts out, then monitor it over the next few months to see if it seems to be creeping back up on me. If so, I'd have to think that the damper is deteriorating rapidly and needs replacement. If not, the hell with it.

You're right, Jeffcoslacker - my bad - idle mixture, not idle.

I assume the Accord motor is balanced, because it has both a timing belt and a balancer belt. But I confess to being less-than-knowledgeable about engine internals in anything newer than about 1960!

The motor mount that gives the most trouble (and is the most expensive, of course, though after-market is a LOT less than Honda's price) is the "left" mount, nearest the firewall. I don't know if it's liquid-filled, but I don't think so (I've had my hands on one - off the car). But it is vacuum-controlled (in the automatic trans model). I suspect it stiffens when you accelerate.

But the reason I know it's a problem dates back to before I even owned an Accord. A very savvy used car dealer was kind enough to take me to a wholesale auction to buy an Accord. He said "you can't drive the car, but start it up, put it in gear and turn the A/C on. If it shakes a lot, that's the motor mounts, and they are expensive to replace." Since then, of course, I've experienced (and had fixed) the problem more than once. Since it's possible to see the mounts, and whether they are new, the repairer can't fool you unless you don't know a motor mount when you see one.

Still, a cheap or free adjustment first sure won't hurt.

Thanks guys, this is really helpful. I have a 1996 Honda Accord LX, it's facinga similiar situation like this, it vibrates / shakes while in gear at the stop light or sometimes when the a/c was turned on.

i having this problem too when im at a stop light i have a 93 honda accord ex coupe and i had the mounts replaced all 4 but my car does still shake at idle any one have a clue also i want to know where i can find a good chip for my year does anyone know im kinda starting on upgrading and getting in to it and want to know whats a good direction to go to get alot more horsepower but still be able to pass smog and have it street legal email me if u can :)

i having this problem too when im at a stop light i have a 93 honda accord ex coupe and i had the mounts replaced all 4 but my car does still shake at idle any one have a clue also i want to know where i can find a good chip for my year does anyone know im kinda starting on upgrading and getting in to it and want to know whats a good direction to go to get alot more horsepower but still be able to pass smog and have it street legal email me if u can :)

Once you've installed aftermarket products onto your car, they don't consider "street legal" ... aftermarket products never considered "street lega" ... most of aftermarket products are non-street-legal anyway.

As far as "pass" smog check. High percentage of shops who do smog checking, they DO know the way to get around to pass smog check.

For starter, a Cold Air Intake system (CAI) is a good start. either with AEM or Injen, they both good brands, deliver the same amount of air.

There might be someone else who could provide you with more informative details.

i having this problem too when im at a stop light i have a 93 honda accord ex coupe and i had the mounts replaced all 4 but my car does still shake at idle any one have a clue also i want to know where i can find a good chip for my year does anyone know im kinda starting on upgrading and getting in to it and want to know whats a good direction to go to get alot more horsepower but still be able to pass smog and have it street legal email me if u can :)

As for upgrades with smog test compliance, look for parts that state C.A.R.B. certified, there's lots of them out there.

For your idle vibe, read the first page of this thread, and do the adjustment.

Summit Racing is carrying a fair amount of aftermarket ricer....er, I mean import :lol: performance items now, check out their website.

If the state handles the testing there's no way to defeat it. I could get a car around it back when we did emissions testing in private shops, but I wouldn't cheat it, not worth $10,000 fine and loosing your inspection permit. A lot of guys would, though.

I am a newbie and would like to thank you for the adjustment info. I was still getting some vibration after replacing the motor mounts and tried your adjustment and after 1 1/2 turns counterclockwise my 97 accord is idling like a champ, thanks again jeffcoslackerhttp://images5.theimagehosting.com/wscrew.jpg (http://www.theimagehosting.com)

This is supposed to be a '94-'97 Accord throttle body. You are looking into the end where the duct from the air filter box comes into it. I outlined the adjuster screw. In your case, you probably want to go out (counter-clockwise) a bit and see if it helps. Remember how it was positioned before you started, and count the turns as you do it. That way tou can return it to where it was if it has no effect. You shouldn't have to go more than 2 full turns, if so, you have other issues. (sucking air or carboned cylinders, etc)

When you feel it beginning to smooth out, continue to turn in that direction until it no longer improves. Then go back about 1/4 turn. That should be about right. It helps if you have someone hold it in gear while you do it, so you can really feel what the motor is doing. Having the A/C on will load it up and make it more obvious too.

Awesome thread. I just bought a 93 Accord with the I4 and the vibration is driving me nuts! I've replaced the rear motor mount and still vibrates.

Do you have a pic of the idle mixture screw on my 93 or is it the same?

Do you know where the idle mixture screw is on 93' Accord? I'm having the same issue as all the rest of these posts,

hey i'd check how low your idle is ive got a 91 accord and it does the same thing and its just because it idles so low its about die you can adjust your idle pretty easy id say go and get a hannes manual for your car and it will tell you how to adjust it if not it could be transmision problems

I have a Hanes manual but it is quite vague on where these settings are located. I have played with the idle but I don't want to turn it up too much as this is hard on the transmission while stopped at lights etc....I can only see that as an artificial fix.