J30 Vibration - the saga continues

[juiceman]

Update, the vibration came back but not as bad. The tires definately had something to do with it.

I decided to check out the car myself and I jacked up the rear. Took off the tires and bolted the discs with the lugs.

I ran the car until I heard the vibration and proped the gas pedal so I could check.. The brakes were pretty smooth. No major vibration from the rear. I looked around and put my ear to parts of the interior and found the vibration was actually coming from around the shifter. This is different than with the wheels on the ground where around 30 mph the vib seems to come from the rear and 60+ the front.

I looked directly under the car where it was strongest and it was where the exhaust mounts to the transmission mount cross member.

I then took a screw driver and felt all the way back along the exhaust and could feel the same vibe all the way back. Had no major vibration coming from transmission or differential or even the drive shaft.

I checked the engine the same way and found no excessive vibe except at the exhaust pipes. Motor mounts seems fine as no major movement in drive or reverse.

My conclusion is that something is causing the exhaust to vibrate and transfer to car. The exhaust mounts look fine but This is where I am guessing the vib is being transfered. Only major thing I noted is that when put the wheels back on and drove it the vib was not as bad. and eventually became progressively worse. Same as last week when the michelins were put on.

I checked the timing and all ok and the car does idle well. The only thing out of the ordinary today was I had the quick start and turn off problem that I have read about. Car eventually started and no major problems.. Funny thing is that the same thing happened on my Honda Civic today. Was really cold for FL. New fuel filter put on <2K miles ago.

I guess I am glad that it does not seem to be anything major in the suspenson, brakes or driveline but really wonder what it could be. Is the exhaust always prone to vibration? or do I have a cat converter problem that is causing a backup and the exhaust waves are not passing as they should giving me a harmonic problem? or something else. Could it be a problem with the egr circuit that would cause a vibration in the gases thus the exhaust?

Any input would be appreciated. No error codes by the way.

Dave the Juiceman:help

[PalmerWMD]

Exhaust hangers get old.Then hang lower and as a result the exhaust may hang lowenough in part to touch on somnething it should noy by design. Thereby transferreing vibrations.

Are those mounts/hangers original?

Fred...

[juiceman]

almost 66k miles. Had car for 6K of that. As far as the records show yes they are original. They seemed all pliable and not dry but I know that elastemer properties do degrade with time and heat. Could transfer the harmonics to the main supports. I do not see anyting touching. I uess I have another wuestion too. There is a counter weight on the ehaust to the rear, I assume that this is a weight as it just hnags in the air attaching to nothing.

I will see what others have to say but will probably replace them out when this is all over and done. I guess I do not want to throw parts at problems with out alittle more looking into. Costs money and wastes time.

Thanks

Dave

[Q451990]

This is a common problem on the Q, so I'd assume it's a very similar design on the J. Any 10 year old rubber component is due for replacement. If I recall correctly they're not that expensive. Since you can see that there's a definate problem there, I'd say they're the next step in getting your car vibration free!

Heath

[VimyJ]

Juiceman, I am interested in how your battle is going. Yes there is a harmonic balancer for the exhaust near the resonator. Could your problem be drive shaft related? I am experiencing a vibration that must be related to the shaft. I described this phenomenon in the "Infiniti Mechanic" section some weeks ago. I have a vibration occuring when I lift my foot off the gas with the vehicle speed over 70. It is, however, intermitent and seems to vary in intensity with how quickly I lift my foot. The quickier the lift the more noticable the vibration. The drive shaft is the primary suspect because the vibrations only happen at speed and do not seem RPM related. After all, the drive shaft speed correlates directly with wheel speed. I do not have this faint shuddering at the same RPM in 3rd gear, for instance. Futhermore, I remember looking at a list provided by Jim in Scottsdale of "frequently" replaced parts in the J30. The drive shaft placed fairly high on this list as I recall. I might have this list somewhere in my notes. I check and post the list if I can find it.

[VimyJ]

I finally found the list. I think it might have been provided by our old buddy TJ. Wow, I'd forgotten how much good stuff I filed away!

The list:

- J30 common problems and approx parts cost:Illumination switch (dimmer for interior lamps)$50Window regulators $80Timing belt (new belt is Kevlar-100K mi), tensioner, thermostat, water pump optional $155Water pump $75Driveshaft $430- usually around 70-100KInjectors $95Sunroof repair kit $31Sunroof tray $500sunroof motor $160Sub-par radio power supply $100-300 repair The J30 is the most relaible model in my experience. If you live somewhere that has snow, you will need snow tires (rear minimum) and 200 or so pounds of sand in the trunk.

[juiceman]

I thought the same thing about the drive shaft but when I touched the screw drive to the center support and the diff I could not feel a vib. I also determined the rotation of the shaft and touch the shaft and smooth as glass.

I never read anything about the q exhaust mounts but I will do a search about it.

Mine is vehicle speed related. No major difference gas on or off. That is why I focussed so much on the tires. Got tired of everyone telling me I was crazy so that is why I put the car up yesterday. I am 90% sure it is exhaust related, just wanted to make sure that it wasn't something else causing the vibe in the exhaust. Haven't worked on many cars while running so Am not real sure how much vib is ok.

From all that I have read, your problem does seem Drive shaft related. I did alot of searching about vibration and all related issues. Do you DIY? Seems like that would be tough to change without high jack stands or a lift.

I just get nervous when my cars are not functioning normally. Being an engineer I never like to feel vibration. My wife on the other hand may enjoy the vibrationin the seat. HA HA.

Good luck with your car VimyJ, let me know how it went with the drive shaft. BTW my radion is on the list after vibration. Seems your list is accurate.

[Q45tech]

The problem with jackingup a car with an isolated rear subframe is to use two jack stands, one on each rear bottom of the shock lower attachment. That way the springs are normal as is the rear suspension and distance from the road..........the car is normally level and the driveshaft angles are at nominal.

When we use a 4 post frame rail lift the vibration changes as the rear wheel droop changing the halfshaft angles and letting the rear subframe droop down an inch or so.Also the 4 post arms dampen the level of the vibration transfered to the body!

As an example a failed [worn out] transmission mount from good to bad shows less than 1/3" movement [compression].

The major reason the Q /J had a 4 year or 60k body and non drive train warranty is that's how long they expected the suspension / isolation components to last [not the metal arms] but the rubber and shock absorbers.

Primarily a function of weight [obviously less stress on a 3000 pounder vs 4300]..........the weight shift in an equal turn is 43% more on the heavier car.

Luckily most people don't understand [can't articulate] the problems or much more warranty work would be done but then again there is no policy about wear and tear and you don't have accurate vibration test equipment to measure the increase in vibration scientifically. Many Lexus dealers do as ISOLATION is a selling point.

I have been fighting vibration for 12 years on the same car it is a complex problem since it is more than 1 or 2 things and the mathematical interaction between them simultaneously.

Not until you known your tires and wheels are perfect can you start working with hubs, rotors,and bearings.

Owners with aftermarket wheels and EVEN LOCKING lug nuts don't understand that even the small difference [extra weight of the lock] can bring the whole assembly out of balance.

You cannot use "on the car balancing" on the rear wheels because of the likelyhood of DESTROYING the Viscous LSD!!!!!!!!!!!!!!!!!!

[juiceman]

I will call scottsdale today to order hangers and supports.

I thought about the hanging suspension but could not jack my car up properly with my tiny jack. Can't wait for christmas as I hinted to my wife about this.

By "on the car balancing" do you mean with a machine that spins the wheel while on the car.? That I assume would cause damage to the Differential. I never heard or saw one in my neck of the woods

I do not use locking lug nuts. The mechanic had checked the runout of the rim on the car, assuming the rim is true when mounted on the car I would assume the hub is true also. The rotors are not bad at all, although I will eventually resurface them. I laid my digital calipers across the surface, (pretty flat surface) and did not see any problems.

Will update when I get the hanger installed

[Q45tech]

Never seen a true perfect used hub [the specification is 0.0028"], the amount of rust [on the hub and inside of rotor hat] make anything but both brand new suspect. This runout gets amplified by the increased diameter of the rotor [whose spec is also 0.0028"] mounted and torqued perfectly to the wheel.

After I replaced the right front bearing and hub [with a brand new perfect rotor] after a few hours of work I was finally able to get the assembly within 0.003"........the stack up of tolerances.

Doing the same to the driverside I was forced to use a BrakeAlign 0.006" stainless shim but was able to achieve 0.001".

When you mount perfect rotors on imperfect hubs or bearings the perfect rotor soon becomes imperfect..........transmitting vibrations as the high spot hits the pad on every rotation so the frequency show up at 55-65 mph [the same as an imbalanced tire]! .......Without the brakes even being applied......gets worse as you brake.

On the car balancing has primarily been replaced by the Hunter radial force tester but both require training that may not be available from the typical technican without 10 years of experience.

On the car brake lathes are the norm at dealers to mistrue the rotor to match a bad hub so everthing ends up closer to true, until some idiot removes a rotor and reinstalls it out of sequence creating a serious out balance situation!

Trying to make a car with 60,000 miles drive [feel like brand new] is a challenge and unfortunately if a parts goes bad at 60k you will need to change it again at 120k and 180k [assuming the same roads and stress].

On my Q I am on my 5th set of upper links and 4th set of tension rods. 2nd sets of everything else, 3rd set of factory wheels, 4th set of shocks. 10th set of tires! 3rd set of transmission mounts 2nd set of motor mounts [needs new ones now]. New drive shaft has 120k now.Some things last 20-30k some 60k some 120k very very very few lasted 200k.

[juiceman]

So new to this car that everything is a learning experience. If replacing parts is what it takes, so be it, as long as I have the experience to replace the right part for the problem the next time.

This car is so quiet and smooth that any thing out of the norm will make it feel wrong.

Plan on keeping this car till it dies so I have a lot to learn but what a ride it will be

Thanks for the input, will update after new hangers are installed

[VimyJ]

I have been fighting vibration for 12 years on the same car it is a complex problem since it is more than 1 or 2 things and the mathematical interaction between them simultaneously.

Vibration is my life. As a musician and especially as a trombonist, frequency is the name of the game. A fact of life is that all tuning systems involving more than three sources of vibrations (tones, frequencies) are compromises. The piano keyboard is out of tune by design as a compromise to keep it relatively in tune throughout its range and in every key. This is why a good symphony orchestra has a such a "settled" and colourful sound as each musician attempts "justly" tune every note in every chord.

In an automobile you have a fixed length of pipe that must function as a tuner through octaves of frequencies. This has to be a very difficult feat to accomplish because each and every frequency only has ONE length of pipe that will match it perfectly. Then add in wheel rotations, transmission, cam shafts, road surface vibration, etc., etc., etc. What a mess. It's quite remarkable how well engineers are able to devise systems that work as well as they do.

A pet peeve of mine is listening to "out of tune" jet engines (or propellers) on multi engine aircraft. The low throb that the pilots don't bother to tune up.

[juiceman]

You play trombone? I did thru most of my public school but quit when the highschool forced marching band and defocussed on concert. Instead I went to work but I can understand because I am very sensitive to frequency interference. Must be something atune to musical types.

I will update when I get the parts, calling Scottsdale now

[juiceman]

I hope this is the end

During an inspection of my brother-in-laws vehicle I noticed that his Explorer exhibited the same characteristics as my car except much more severe. His ball joints were shot and the alignment was out bad.

Had another alignment done today at a very reputable shop and the front was out and the rear was out bad. Now the car rides smooth.

The place that did the alignment took 1/3 the time this place did plus I actually got the before and after printout. They set all to very close to nominal. BTW, this shop is always clean and organized. To me that means alot. Care in their work environment means care in their work

SO I did have a tire problem resolved by switching to Michelins but there was also another underlying problem with the alignment. According to the tech, the suspension is in very good shape.

I plan on disputing the charge for the original alignment with my CC company.

Thanks to all for the inputas always a pleasure

[Mayhem_J30]

I hope this is the end

During an inspection of my brother-in-laws vehicle I noticed that his Explorer exhibited the same characteristics as my car except much more severe. His ball joints were shot and the alignment was out bad.

Had another alignment done today at a very reputable shop and the front was out and the rear was out bad. Now the car rides smooth.

The place that did the alignment took 1/3 the time this place did plus I actually got the before and after printout. They set all to very close to nominal. BTW, this shop is always clean and organized. To me that means alot. Care in their work environment means care in their work

SO I did have a tire problem resolved by switching to Michelins but there was also another underlying problem with the alignment. According to the tech, the suspension is in very good shape.

I plan on disputing the charge for the original alignment with my CC company.

Thanks to all for the inputas always a pleasure

if you don't mind me asking. how much was the alignment and was it all 4 wheels?

[juiceman]

The first was 49.95 the good one was 69.95 both were four wheel. I think the first shop never had their machine calibrated. plus their shop was in total disarray. I should have known.

I have used some of the chain shops that offer the 3 year package but my experience of late is that they do not put the effort into the reaaligments. Experienced with my late minivan which always pulled and never got resolved. They never got to nominal , just in spec.

I do not know if this is alot or alittle but I think I finally found a decent shop that uses the BG products that is honest enough for me

Just had a BJ inject/fuel rail/intake cleaning done by them and it was $100.

Hope it helped

[juiceman]

Well I guess it was not the problem, the vibration slowly came back over two days. Some days it seems better than others

It seems that when the car was serviced for tires and such the last few times the drive shaft and sub area shifted into alignment for a little while

I just had the car back in to the shop and they checked the alignment and it is dead nuts. They called around and was told by two local infiniti dealers that the J30 design had problems and the whole drive shaft assembly needed replacement.

I called Scottsdale and got a price and will be checking with Lisle tomorrow.

My big question is, can I wait a month to do this or do I risk damaging something else. With the holidays here and my wifes big xmas habits things are tight. It only has 66K on it but I guess with my luck lately it would be the case

When I replace it, is it something you can DIY with some stands or should I just let the local shop replace for 130.00

I guess the center bearing wore out but is not replaceable individually and the whole thing must be replaced.

Do you agree with the findings?

BTW, the car is still way smoother than my Civic and much more fun. :help

[greg_atlanta]

Yes, driveshaft can wait. I put it off for 3 years (92 Q).



Common problem on early Q45s, same setup. If it's REALLY bad it might hurt the differential or transmission, but I don't think they get that bad.

Has transmission mount been replaced? That's a quick fix that solves a lot of Q45 vibration issues, so I'd assume J30 would be similar.

[VimyJ]

That list of frequently replaced parts is a good statistical sample of what will probably go wrong. I'll be interested in how you resolve this situation as I think a new drive shaft is somewhere in my future, too. I hope that I don't have another problem that I'm going to open a new thread with.

[juiceman]

Replace all exhaust mounts and transmission mount today. Marked improvement but still not perfect. Now it seems that around 60 the vibration seems to come from the front of the car. I inclined to say motor mount is next to be replaced. The is more engine travel when in reverse than in drive.

I would tend to feel that it would be the left motor mount since there is more play in reverse. Anyone know how hard this is to replace?

I finally feel I am getting somewhere. I am glad I did not replace the drive shaft yet as now I feel that this is not the culprit.

Any input would be greatly appreciated

[VimyJ]

I added this snippet to my files in my quest for all things J30.

"I feel a vibration coming from the center of the car between 65 and 75mph, where does it come from? This problem is usually caused by a failing driveshaft carrier bearing (once out-of-balance tires are ruled out). Failure of this bearing is common in aging 300ZXs and is usually solved by replacing the carrier bearing itself, although if the vibration persists replacement of the driveshaft may be necessary. Note, driving with a vibration of the carrier bearing can cause transmission damage/failure."

As you can see this item refers to the 300zx and probably comes from the Z32 site (I should keep better track of my sources). I dropped by a local specialty drive shaft place and they quoted $90 for the install. I haven't priced the part. Just some food for thought. However, I maintain that you should consider the most statisically likely problems first. That said, I hope that replacing the various mounts solves your vibration problem once and for all. Good luck and let us know how it goes.

[Q45tech]

Ask them how much they will charge to index the replacement shaft per service manual requirements. There are 4 possible phasing positions and it takes 15 minutes to measure the runout in each, then select the minimum.

Just slapping in a new shaft is risky examine it closely for any transport damage.

Everything rubber is worn out at 6 years! Just keep that in mind

[NWilner]

A pet peeve of mine is listening to "out of tune" jet engines (or propellers) on multi engine aircraft. The low throb that the pilots don't bother to tune up. [/QUOTE]

BTW "synchronizing" multi engine airplanes is considered important, if not required. Simple planes do it by ear; more complex have electronic synchronizers.

Nonetheless as your ear attests they are sometimes out of synch.

The difference in RPM is, incidentally, equal to the number of beats per minute.

[VimyJ]

BTW "synchronizing" multi engine airplanes is considered important, if not required. Simple planes do it by ear; more complex have electronic synchronizers.

Nonetheless as your ear attests they are sometimes out of synch.

The difference in RPM is, incidentally, equal to the number of beats per minute.

Or beats per minute or per second. The destructiveness of mismatched frequencies is most evident in earthquake damage to tall buildings. Some structures that are built to with stand a given magnitude of sesmic event have failed in quakes that were below this threshold because of incompatable frequencies. Aluminum, a brittle metal, would be very prone to fatigue failure if engines weren't "tuned" properly. (Not to mention driving some of the paying customers nuts.)

[juiceman]

The New New shaft still exhibits the same but not totally characteristics. The low end is fine but once 50 and above is reached it vibrates

I am at whits end. Could it be torque converter shudder? if so what are signs other than vibe?

Man any guesses would be great.

[VimyJ]

The New New shaft still exhibits the same but not totally characteristics. The low end is fine but once 50 and above is reached it vibrates

I am at whits end. Could it be torque converter shudder? if so what are signs other than vibe?

Man any guesses would be great.

Juicy, this problem of yours must be drivng you friggin' crazy! Since it seems speed related, I'd go back to trying to get the tires rebalanced. Was the center bearing replaced and the driveshaft checked for minimum run out? I'd also think that if it were the TC the vibration would be absent when you accelerated and disengaged it.

[lonallenq45]

Juiceman,

I am sure you already mentioned this and I can't seem to find it, but what kind if tires are you using?

I had a similar problem in the past and it was due to the tires not being rated for the weight of the car. No matter how many times I had the tires balanced, when under a load they would vibrate between 55 and 70 mph. I had to have the tires load balanced to show that the problem was truely the tires. When I asked the tire retailer about the load rating of the tires, he gave me a look like "What are you talking about?" I had to get him to look it up and compare it to the OEM tires on the vehicle. The tires he sold me should have never been installed on the car. I was able to get him to refund me the entire cost of the tires and apply it to the proper tire. The problem has never returned. In the process of all this I had replaced the drive shafts, the suspension and the transmission and all the while it was the tires.

Just thinking out loud...

[juiceman]

They are michelin Harmony but now that you mention it they have a load rating of 93S (1411@44psi). I did not realize they were s rated.

Man I do not know where to go.

The vibration seems to be from the middle of the car not the outer edges as a tire problem would cause.

Just don't know

[juiceman]

BTW the vibration is a higher pitch than tires will cause

Stays around when shift to neutral

Not evident at same engine rpm in other gears, speed related

Could it be bad bearing in transmission?

[maxnix]

I would go back to the dealer and explain what you have done, and have him put at least XGTH4s on in the correct size.

Remember what Q45tech says about tire construction (and inspection) vs. speed rating. Statically they may be strong enough. Dynamically, they may be overstressed.

Harmony? Maybe they are out of tune.