94 q45 faint vibration in sterring wheel @ low speed that seems to come and go

[don kramer]

this new car to me seems to have non-leaking struts all the way around but boots are in need of being replaced. Have boot replacement planned and then will install jeff's front suspension support.

Curious if I am missing anything that might account for this faint vibration. Low enuff speed that does not appear to be tire balance but will get that done along with alignment. this may be a premature post but I used to be pretty good wrench twister and none of those seem to be the stimulus.

any thoughts appreciated and i will post my findings after all the above details are accomplished. Just thought there was something else worthy of checking while I have the struts lowered from their top position to install boots.

Do not know the age of the struts (rumored to have been changed out) and thought about just replacing all with the blues while I had it off but the car rides well know and no leaks from struts. Again doing it right and not doing it twice is my choice.

I am always amazed each time I spend time here with the wealth of information not to mention the helpful and thoughtful posts by the members. hope this is the right place for this this time.thanks,don

[Peterofdevon]

I've been thinking about these vibrations for a while and I believe Q45tech has offered an answer we sometimes overlook. I remember a post saying that the G50's suspension is prone to harmonic vibration from directional tire tread patterns, especially between 40 and 50 mph.

I've noticed that in this MPH range that the vib comes and goes. It seems as if the tires get into a rotational lineup with each other causing a vib, then, as they roll and get out of sync with each other, it goes away.

From what I've experienced, tread pattern is key here as is road temp and tire compound.

Any thoughts from others?

Peter

[Q45tech]

Shocks are FAILED long before they leak, shocks last at best 4-6 years and no more than 60,000 miles before they are significantly weaker than new.

Histoically the rear start to go first with an mild undulating bobbing up and down motion on a smooth interstate..............feeling the springs cycle.

Tire radial force and misbalancing plus rotor warpage are additive and vary with temperature. As you turn the tire wheels, rotors get out of phase and the imbalance move around relative to each side.

Often the rotors will need retruing every 6-8,000 miles to achieve perfection, this is before you feel a vibration when braking........a little of each error can be additive.

Start with premium Michelin tires, on tested and perfect wheels, then true rotors to better than oem spec and you will have a ride you never dreamed possible if all suspension components are as brand new.

The above is expensive to maintain since things wear and go out of spec so fast because of the weight of vehicle.............things were made too flimsy to save weight.

Upper links last 30k nefore they get loose and sloppy, tension rods, bushings, suspension arms and mounts bend....................a never ending nightmare to maintain as new.

People standards and pocket books vary as to whether they are willing to spend $3,000 or $4,000 per year to achieve perfection.

[maxnix]

I've been thinking about these vibrations for a while and I believe Q45tech has offered an answer we sometimes overlook. I remember a post saying that the G50's suspension is prone to harmonic vibration from directional tire tread patterns, especially between 40 and 50 mph.

I've noticed that in this MPH range that the vib comes and goes. It seems as if the tires get into a rotational lineup with each other causing a vib, then, as they roll and get out of sync with each other, it goes away.

Not in my experience. If you are in 3, sounds more like you are experienceing a failed rear (transmission) motor mount.

[goody90q45]

Curious if I am missing anything that might account for this faint vibration.

Transmission mount and exhaust hangers. If you haven't done it yet you're due. Is the vibration at about 2250 rpm at 45-50 mph in 2nd gear and then again at 65-70 mph in 3rd gear?

This is a really easy DIY if you don't mind laying on your back under your car and probably wouldn't be more than 90 minutes labor if you took it to a shop and supplied OEM parts. Look at Q45.org for a writeup in the Tech Help section or search here using Transmission Mount as keywords.

[maxnix]

Is the vibration at about 2250 rpm at 45-50 mph in 2nd gear and then again at 65-70 mph in 3rd gear?

Actually in 3 and D in my experience.

[don kramer]

Q45tech, you are somthin' along with all the other posts offer plenty of checking to find the culprit. This vibration is almost like a tire out of round or a flat spot since it shows up below 25 even 20 MPH. Not necessarily only on starting out but generally coming and going through the day.

I used to change cars like many change socks. I thought I might just pick this up and use it in between while I found another Lexus LS. After reading here over 35-40 hours since I joined, printed over 150 pages of input from all of you, I have come to understand what I have here and I am not sure I can get a divorce from this car and go back to something else.

Kudos to all of you, gracias gracias. Where on earth can a person post a question at 11:49pm and have more legitimate answers before 7 am while he sleeps than were posted here with sure more to come.

I will wring this out and fill all of you in. I knew I was not alone with this issue.

Q45tech, Is there a good way to verify strut age or pending failure if no records are available. This thing rides like on a rail. Remember I am at the foot of the rockies and have many winding banked and unbanked roads and I have never driven anything as stable with less body sway than this. I am inclined just to replace the struts and be done with it then I know, unless there is a better way to determine age. If I am installing strut boots and have the top off of all wheels, other than cost is there a reason not go ahead and just put on the "blues" and the other components i have read about and printed already? As I said above I believe I got a marriage cert. with this one instead of a title.

thanks again gentlemendk

[don kramer]

goody, these were on the list as well but further down. the vibration is very low rpm while rolling and not related to engine or drive train I don't believe but I will exhaust your suggestion as well and get those done.

As I make the list of parts outlined in another post from Q45tech on what needs to be done on this year and model, I don't recal one location for most of these components from nissan or am I mistaken. Saving a buck or two on parts is always good. I have a company name, tax id and used to do sales and service years ago. the old man's back just doesn't do as well as some of you younger ones here.

again many thanksdk

[silkysmoothyjud]

Hello, I'm had the same problem myself, but I licked it (kinda). The first thing your want to check is your alternator belt tensioner. Loosen the nut that holds the wheel in place and loosen the adjustment at the bottom of the assembly. Did you notice that the adjuster moves in and out slightly? There was my problem!! The fix, I totally rigged it. I know, I know, I am not worthy, but my car does not have a major vibration issue anymore. (my rear view mirror would vibrate from said problem) To rig, screw a metal hose clamp to tighten the long adjuster bolt to the lower part of the assembly(tightly). Also, I took it a step further by modifying the nut (with washers) that sits behind the tensioner wheel itself to make the wheel stick out farther. Finally, I loosened the belt a little, but not that much. The result, silky smooth baby....I still have a minor vibration when my wheels are straight, but that is from doing my tie rod boots, I must be off a thread or something.

[96Qowner]

As I make the list of parts outlined in another post from Q45tech on what needs to be done on this year and model, I don't recal one location for most of these components from nissan or am I mistaken. Saving a buck or two on parts is always good.

The best place for parts is usually Joe at 1-888-216-5328. They're NICO sponsors and offer a healthy discount to members, as well as being extremely knowledgeable about the 1st gen Q45s. Tell 'em you're from NICO.


Modified by 96Qowner at 9:07 AM 3/1/2007

[silkysmoothyjud]

A good way to tell if it your motor causing the vibration is to get rolling, throw it in neutral and turn the motor off to see if the vibration stops. Then you'll know for sure if it is one of your motors moving parts. The vibration in my Q came and went at low speeds, but it was really bad at speeds over 100.