Vibration at idle

Hey,

Thanks for the reply. I am unfamiliar with the nuts and bolts of automatics; I've been around sticks since age 10 so I know about manual transmissions and how to know whether they work fine or have a problem. As for automatics well. I may need to learn now.
On second thinking my description was incorrect; if the torque converter multiplies torque it should allow the engine to rev faster when driving uphill (more power is needed), and conversely when going downhill. Still, I notice the shift being quite imperceptible now.

Thanks for the trans throttle note too. I re-read the Honda service manual and it says that it is permissible to adjust it to "shorten it" if desired (but by not more than 3 mm.) Now it will start moving the lever in the transmission as long as the throttle is moving.
So if I shorten it a little I would have a more immediate response to downshift when pressing the gas.

I replaced all the engine mounts a few months ago; vibration has not changed. Tried adjusting them twice (as per service manual) but it did not help

BMRFIXIT: The car is EFI but it does not have an EACV valve -the 89 accord has such a valve but not the 86. Instead, the 1986 has a idle valve that sits close to the brake booster with two hoses one coming from the air filter and the other going to the intake manifold. It opens when it is energized; if it is unplugged it closes and no extra air comes in.

As much as I dislike disassembling the transmission (it has no oil pan) your suggestion of inspecting the oil pump complements the service manual. If the oil pump is seizing or its screen is clogged with debris the symptoms would be the same, right?
Besides, sometimes I see operation of the idle valve when apparently there is no load on the engine. So there is some load coming from somewhere; what would happen if I do a stall test?

Thanks!

One last thing: I did a stall speed test today. After warming up engine and transmission I followed service manual recommendations to do it.
I tested in D4, D3, 2, and R positions waiting a few minutes between tests to cool the transmission.
Engine stall speed (as measured by dashboard RPM): about 2,750 rpm in all gears.
The manual specified a stall speed of 2,650 rpm for FI engines with acceptable boundaries between 2,500 and 2,800 rpm. Also says that stall speed should be the same in all gears.
Does this help in anything? Thanks!

My 1998 Honda Accord LX has a bad vibration which is worse when accelerating or decelerating. It is noticable between 30-70 but virtually non-existent at 70mph or above. As soon as I take my foot off the gas and start to coast, it shakes like I have a broken belt in one of my tires (my tires were checked and they're fine). I've had every item replaced in the front end; struts, all bushings, ball joints, tie-rod ends, and end links, rotors, pads, 4 brand new wheels. A 4-wheel alignment was done, tires were balanced not once but twice while I stood by and watched (all good). First I suspected struts so I replaced those. Then I thought the frontend components were just worn out so I installed an entire new frontend kit (Honda parts). Then I was told that I had 1 bent rim so I bought a whole new set. After all of this, I STILL have bad vibration as described above! I sure hope some sharp Honda mechanic can tell me what's drastically wrong with an otherwise wonderful moneypit. Er. Car.

Hello to all,

Sorry for disappearing for so long!

School has driven me crazy the last few months. Besides, the car drives OK except for the nasty vibration at idle. We put the transmission in N when stopping at lights and the vibration is lower although I can still feel it.

Regarding the torque rod I replaced its bushings a while ago.

As said earlier, vibration is worse when the car is not in neutral or park. R, D4, D3, or 2 does not make a difference -vibration is higher when in drive. It seems to me that while the engine is in neutral the vibration is somehow isolated in the engine (although it is still felt).

I eventually go back into trying to solve the vibration problem but I want to learn more about auto trans and especially torque converters, since the service manual pointed out to them as one possible cause for idle vibration.
I saw an online video in which they showed a locked-up torque converter; it had a clutch-like device attached behind one of the turbines (I think the one that drives the transmission). I wonder how a torque converter gets worn out when the car is driven mostly around town with all the idling in gear. It seems to me that all that wasted "torque" idling should produce heat which in turn should accelerate wear. In other words, what parts get worn out in a torque converter?

Thanks a lot!

I don't hear a clunk or grinding when going straight or turning. Are you sure that it could be my CV joint(s)?
Thanks,
Tim

I replaced all the engine mounts, plus the ones in the top torque arm.
The one on the timing belt side was destroyed. They are OEM replacements (BeckArnley and Anchor if I remember right).

Anyway, the vibration did not change. OK at idle but bad when in gear (Ds or R). Once rpms climb above 1,000 the vibration disappears and car drives OK. Transmission works OK

I tried loosening and then tightening the mounts; nothing changed.

I've re-read the thread. One earlier posting talked about checking valve bodies for the lock-up valve that might partially engage. I' kind of lost; car is drivable so I do not pay a lot of attention to it but I'd like for it to work as it should again.

I have browsed a lot of the Q&A's on the forum, but I haven't seen one that's quite similar to mine.

Car: 94 Honda Accord EX, 150,000 miles
The vibration can range from moderate to ridiculous. The vibrations are constant in frequency and only vary in severity. It occurs between 60 to 80 mph and only under acceleration. It does not come and go, it occurs every single time. I have had the tie rod in, brake rotors, and all serpentine belts replaced very recently, and I have had an alignment done. The problems have persisted for about. 5000 miles, during which I have had tires replaced, rotated, and balanced, all to no avail. I can see no apparently irregular wear on the tires and they are all inflated to factory specifications. As said before, the vibration is not present at idle or speeds below 55-60mph. The problem seems to be very slightly alleviated by a full tank of gas. At least when presented with highway-level mild corners (I can't do tight corners at 70mph), there seems to be no noticeable effect on the vibrations.

The possible causes that I have deduced by browsing around are:
-worn axle (mechanic's diagnosis)
-axle bearing
-out of round tires/wheels
-CV shafts/joints
-wheel bearings
-lower ball joints
-loose fan belt
-worn motor mounts
-driveshaft U joints
-low transmission fluid

I have already spent more than enough hours at the mechanic's, and it's not feasible to stab around in the dark by replacing everything until it goes away. If you could at least name the most likely culprits, that would be greatly appreciated.

I looked underneath the car; the crossmember does not look like bent or the engine sitting on it.

Need to loosen upper torque rod to see what happens. I'll post updates. Thanks!

97 Honda Accord, 113,000 miles, standard. When I am idling, my whole car vibrates. As soon as I put my foot on the accelorator, the vibration stops. The idling vibration is more intense when I turn on my AC or use the power window controls.

Thanks!

Hi Bruce -

It idles around 1500rpm. I have taken it to 2 mechanics and they are unsure what the cause could be.

Something it just started to do this month is in addition to the shaking, the engine makes a whining noise when I turn the AC on.