Vibration at idle

check belt and tensioner recommended replacement is 60,000 mi. then check a/c for bad clutch or compressor. Has it been tuned up? The A/C creates load on the engine and if the plugs are worn you may pick up a slight misfire.
Also try servicing the throttle body, you may have a slightly low idle due to coking and cleaning it will help

See the guide below

https://www.2carpros.com/articles/throttle-actuator-service

Too much engine vibration when idling; the car rattles as it was going to fall apart. Engaging transmission amplifies the rattling. But once the engine is above 1,000 rpm the vibration subsides and car runs fine, gears shift smoothly.

No misfire felt; checked unplugging each wire to see difference and you can note the difference when a spark wire is unplugged. Same for fuel injectors; when unplugging one of them idle becomes irregular.

The other driving symptom is that when cruising at about 2,000 rpm (about 45-50 mph) I can feel like a slight hesitation; engine does not seem to have too much power at that speed range. Engine has power at highway speeds up to 80mph (I did not press further)

Car passed emissions without problems

Things I checked/replaced

Distributor cap/rotor/wires/spark plugs: new; wires resistance about 1k ohms.

Ignition timing adjusted. Mechanical and vacuum advance work including the cold advance.

Thermostat replaced.

Oxygen sensor replaced. Temperature sensor seems to work as engine changes behavior (idles slightly aster) when unplugging it with engine hot

Timing belt replaced and set at right timing @ TDC "white mark" (someone had confused the TDC mark with the ignition timing mark and car died when idling. I did this when replacing all the seals (car was leaking oil badly). Now it does not leak any oil; also repaired oil leak inside distributor (new shaft seal)

New PCV valve works OK. EGR valve works OK (no leaks)

No vacuum leaks, steady vacuum at about 20 mmHg at idle.

All engine mounts replaced.

Fuel pressure ckecked about 39 psi at idle with pressure regulator vacuum hose disconnected; pinching return fuel hose sent pressure up at about 70 psi (so fuel pump is OK?)
New fuel and air filters

I thought about sending fuel injectors to cleaning and removing intake manifold to check for carbon deposits at the intake valves. What else may be wrong?

Thanks

It sounds to me as balance shaft off
but I do not recall if the 1986 if had one or not
rechecking the timing marks would be my 1st step

also loosen motor mount bolts run engine shift to drive and then to revese
hold position for few
put in park shut engine off
tighten mount bolts

I checked the 1989 service manual I have. I use that manual to do the checks in the 1986 accord I have as it is the closest thing I have. the 1989 accord engine do not have balance shafts with engines being the same (A20Ax).

I checked timing a few weeks ago when checking valve clearance; timing marks were correct ("T" mark aligned and camshaft pulley marks align with top of cylinder head.

I loosen all engine mount bolts twice. The first time I adjusted them in sequence as per manual -no change- Second time I left them loose and drove the car for a couple days. The car shook the same as before with mounts loosened. Later I re-tightened them without any change.

I will check sensors because the other symptom is lack of punch at low rpm. Service manual lists some sensors as possible causes.
My question is how do I check the MAP sensor without a harness? I checked wiring coming to the sensor and it is OK but I cannot check voltage when plugged; manual describes wire color for a harness adaptor but not for the MAP sensor or wiring itself.
I have a vacuum pump; is there any way to check sensor output when changing vaccum?

Thanks!

Tap into the back of the wire plug
measure volts as u pumping the vacuum pump
I would check the vacuum source and if good
unplug the sensor wire and check if better replace the sensor
I do not think it is the map sensor honestly

my next step will be a cylinder balance test
disconnect one cylinder at a time noticing the vibration and power lose
good luck

I checked the MAP sensor vacuum. It measures 20 inHg. @ idle. Unplugging the vacuum line from the sensor immediately kills the engine. I left it connected with a 'T" connector and vacuum changes w/engine load; for double check I connected another vacuum gauge in other point of the intake and the readings were identical.
I did not check the electrics though. The other sensor I was thinking about is the atmospheric pressure sensor located in the cockpit. Also, the accord service manual I have lists throttle position sensor as something to check when idle is rough/lack of power. EGR is listed under "rough idle" but I checked the system and there are no leaks (the valve was pretty clean).

I did the power check. the engine vibrates worse when unplugging any of the plug wires without any noticeable difference about which plug it is unplugged. It runs rough and you can tell the difference.

A few days back I did the same with the fuel injectors unplugging one at the time; it was the same case -engine running worse and without difference regarding which injector was disconnected.

This problem (vibration at idle) grew worse over time; also is noticeable a lack of power at low and middle range.
When I got the car it had a vacuum leak (broken brake booster) which I solved. Then the idle speed was fast so I cleaned and readjusted the idle valve (the one behind the throttle body w/water hoses attached to it) and idle became more regular. Later I removed and cleaned the throttle body (idle bolt was stuck).
Car vibrated badly when engaging A/C; the A/C fast idle solenoid was dead. I replaced it and that subsided until the vibration on the engine itself became worse. you can feel the low freq rumble even when the transmission is in neutral or park. Engaging transmission makes it to be transmitted to the whole car.
Funny enough, once the car starts moving the vibration stops and car runs normally although with lack of power at low speeds. It has no reaction unless I floor the gas pedal in which case it will downshift two gears and blast forward. Power seems OK at speeds above 55 mph.
Gas consumption also seemed to increase lately. No oil consumption and it does not burn oil; I have barely added any oil since fixing all the oil leaks.

I am running out of ideas. I may continue driving it until whatever is getting bad makes the car not to run anymore, but knowing these Hondas it might take forever for it to happen.

Ah, no computer codes (no dashboard light and LED on ECU does not flash any code)

Did you try to advance the timing a bit
do it by ear just to check

I have a 1998 Honda Accord. I took it to the service station to get the break pads changed and the rotors cut. I also advised the mechanic that the steering wheel was shaking. He said the wheels probably needed balancing. He also advised the shoes in the rear should be changed saying they were below the manufacturer's recommended specs. After I got the car back the car would now vibrate very roughly on the highway at about 60mph and above. I can tell it's coming fromthe the right front side of the car. The faster I drive the worst it gets. I took it back to the mechanic and he rotated the tires advising me that a rim was bent and it was causing the vibration. I didn't have this problem b4 I went to the mechanic. Please help...any ideas on what is wrong with the car. *note* weeks before I took the car to the mechanic for the brakes, I did hit a large brick with concrete that had concrete on top. Somebody (no doubt a kid) left in the street with the right tire. But I never felt a problem with the car until after leaving the mechanic.

Hi there,
A tyre problem could take a while to develop if it wads damaged, i would be thinking tyres, if the shaking is in the steering it will be a front wheel problem, if more of a body shake the rears, start here.

mark (mhpautos)

I checked advance w/the lamp; it is almost right at the red mark.

I drove the car as it was for a while as things got busy and I could not give any attention to the car at all. But fuel economy was poor and car was unresponsive at low range (about 2k rpm), so I decided to do something about it. I removed the fuel injectors and sent them to a cleaning service.
I just got them today; I installed them and drove the car a few miles.
Bad and good news. The bad news is that idle vibration is still there although it seems to be vibrate a little less; more driving would be needed to make a better judgment.
The good news is that it drives a lot better; hesitation and lack or responsiveness are gone. Now tapping the gas pedal gets an immediate response from the car, and a little extra pressure on the pedal would downshift the transmission without a problem; before I have to floor it if I needed extra acceleration.
The before-and-after figures they sent me showed an increase of flow of about 10% on each injector. They said spraying patterns for the injectors were off too. I cannot tell on either but I can tell that the car has improved.

I'll drive it more, fiddle a little with ignition advance and go back... sorry for being gone for so long!

Would the rough vibration be the tires also? The vibration exists even if the car is not moving very fast. It's just not as strong. Could it be an axle problem?

Its great news and NOT bad at all !
let me know what happens
happy driving

Hi there,

The tyres would be the first place to look, as drive shafts normally don't often cause a problem, a small pressure bulge or a lost wheel weight can make a big difference, check the simple things out first, eliminate the tyres and rims, first.

mark (mhpautos)

I've been driving the car for a couple days. Cleaned fuel injectors have made some difference especially in performance; the car feels alive now. I cannot tell about fuel consumption as I have not refueled yet but I would expect improvement out of better flowing injectors and correct spraying pattern. Overall, money well spent

But the vibration at idle is still there. I still have to fiddle with ignition timimg although it was dead at the right mark and I know the distributor works OK (I disassembled it to replace the low shaft seal and inspected all the internals)
I am suspecting that something else is going on; as I do not know about automatics I wonder whether the problem is transmission-related.
Overall, transmission seems to work OK; it shifts smoothly and no strange noises come from it. The only "odd" thing is that sometimes when driving at speed (40+ mph) It would engage 4th gear with no problem and then you may feel like something else "engages" and the engine rpm lowers a little (torque converter lock-up?); alternatively, that "engagement" ceases and the engine gains a few hundred rpm (about 500 rpm). This is the only noticeable thing; I checked the downshift (is that right) cable and it starts moving when the gas cable starts moving.

When I replaced the rear crankshaft seal (it leaked badly) I drained the torque converter and the transmission and put new fluid (the old one looked quite dark) I used regular Mercon III fluid (owner's manual specification for the year/model was Mercon/Dexron). However, after reading on some forums that you should use only Honda ATF, I decided to use an additive that supposedly increases the grade of the transmission fluid up to a level suitable to that of Honda ATF.
Although the vibration at idle is still there, the transmission now shifts even more smoothly than before.

Finally, I read a Honda service manual and for excessive idle vibration it suggests as causes
adjust idle speed
defective torque converter
It further suggests to inspect the oil screen for particles of steel/aluminum and if there is no cause for contamination (if found) replace the torque converter.
Unfortunately, you have to disassemble the transmission in order to see such screen (no oil pan)
Is it possible that the torque converter would cause this? How it may be checked?

I test drove the car yesterday on the freeway to check for the converter lock-up; the "engaging an extra gear" that it used to do is gone.
I can feel that the converter lock-up engages when the car goes uphill and disengages when it goes downhill but it is slight (you need to look at the tachometer to see the change in engine rpm). I cannot tell whether it was the cleaned injectors or the "enhanced" transmission fluid that make it work better.

Anyway, the vibration remains and after reading the service manual for my model car I suspect that the torque converter is the problem. No matter how I adjust the idle speed the vibration is there.; it only disappears when engine revs higher than 1,000 rpm

Assuming the torque converter is defective, should I go ahead and replace it at once? I wonder about the risk of it shoveling the transmission with shavings and debris if left for an extended time?

Thanks for the help!

Suspect tranny oil pump
you may have to remove and inspect
To verify if there's too much load on a fuel-injected car, check the voltage drop at idle between body ground and the EACV-to ECU wire. (For example, you'd check the BLK/BLU wire on a '90 Accord, or the BLU/RED wire on a '90 Prelude.) About 10V is normal. A reading of 2-4V indicates that the ECU and EACV are compensating for some extra load. On a carbureted car, run a trans stall test. The stall RPM will be below spec if there's too much load.
If the above check confirms your suspicions, disassemble the trans and inspect the oil pump for signs of seizure. If the pump is OK, the lock-up shift valve may be binding, which causes the lock-up clutch to partially engage. If the lock-up shift valve works properly, the only possible cause left is a casting flaw in the main valve body.

My Honda, like many others, vibrates through the steering wheel and dashboard when in gear, with foot on the brake, at a red light. Does not vibrate in Neutral or while driving. I have already replaced all four motor mounts with Corteco Freudenberg parts. I lifted the vehicle up and made sure the vacuum actuator, on the rear mount, was actually moving. I also double checked the alignment of the balancer shaft, everythings ligned up to factory specs. I even double checked all the bolts holding the rack and pinion unit to the sub-frame. Any ideas why my car still vibrates? I'm at a loss.

check all vacuum hoses. as they will cause serious vibration and high idle. also be sure to check your idle air control valve for any faults

Hi,

Just to clarify a little on the lock-up operations.

The lock-up should disengage when going up hill and engage when going down hill. Your description seems to say the opposite.

Improper trans throttle cable adjustment would cause the following:
1. Too short = Excessive pressure. Would cause harsh shifting and early downshift and late upshift. Surging while cruising would happen when lock-up engages and disengages with the slightest throttle movement or road condition.

2. Too long = Low pressure. Early upshifting and lack of accelerating power when flooring the pedal.

Try using a jack to support the engine slightly and see if the vibration goes away. It could be the engine mounts that are bad. For this model it goes bad rather quickly.

[quote:634cf05fa5="ecogabriel"]I test drove the car yesterday on the freeway to check for the converter lock-up; the "engaging an extra gear" that it used to do is gone.
I can feel that the converter lock-up engages when the car goes uphill and disengages when it goes downhill but it is slight (you need to look at the tachometer to see the change in engine rpm). I cannot tell whether it was the cleaned injectors or the "enhanced" transmission fluid that make it work better.

Anyway, the vibration remains and after reading the service manual for my model car I suspect that the torque converter is the problem. No matter how I adjust the idle speed the vibration is there.; it only disappears when engine revs higher than 1,000 rpm

Assuming the torque converter is defective, should I go ahead and replace it at once? I wonder about the risk of it shoveling the transmission with shavings and debris if left for an extended time?

Thanks for the help![/quote:634cf05fa5]

check the plugs and wires, Had it on a camaro , one plug was not working right, would idle and drive but when stopped at light the engine vibrate and would miss fire,

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!!!!

yes and make sure your plug wires are not arc ing against the block. had same problem on my olds.

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!

The stall speed indicates no problem with all the clutches tested. If the strainer is clogged the trans would tend to slip at high speed when insufficient fluid can pass through.

Did you check the torque rod adjustment? It is the one from a bracket attached between the trans/engine and firewall?

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.

The only parts you did not mention are the one(s) I suspect, if you hear any bang when shifting into drive or reverse, have the inner plunger joints on the cv axles checked, if it shifts ok, check engine and tranny mounts...ALL of them, especially with your mileage...Some people describe the shifting problem as a clunk...

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

Great to hear from you again.

Torque converters are maintenence free components that are supposed to outlast the trans and vehicle. For models of the era mentioned, I have yet to encounter any faulty ones. If it is a turque converter problem, you would have issues such as bogging down, loss or performance and maybe a little harsh shifting.

With the trans in N there is vibration indicatiing it should not be a torque converter fault.

Did you inspect the engine mounts condition and alignment?
Was the torque rod correctly adjusted?

I would still say it is the engine mounts condition and their alignments that is causing the problem.

Another thought that I have might be to check the rear bearing on the wheels.

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.

Under the engine between the trans and engine, there is a rubber damper sitting on the crossmember. Check if the crossmember is bent and resulting in the engine assy sitting onto it. There should be sufficient clearance between the engine and crossmenber.

Loosen the upper torque rod and test if the vibration is lessened.

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!

One of the cv joints on the axle is probably bad. since it only happens under load, it would be drivetrian related. A reman halfshaft is the way to go.

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!

I would bet that the idle is too low on the car. What is the idle rpm?

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.