steering wheel vib while idling?

Hi, I have a 99 maxima (65k mile) that I've kept in fairly good
condition. Recently I've noticed that while idling (after the engine
has warmed up), the steering wheel vibrates slightly. I checked the
engine idle speed and it is between 600-700, and according to Hay's
repair manual, this is within spec.

When I turn on the AC, the RPM increases slightly during idle and the
steering wheel no longer vibrates, however, I do sense vibration under
my seats. Once I turn off the AC, the vibration returns to the
sheering wheel.

When I am driving, it is fine. When I am idle, the shaking stops once
I shift to Neutral. It only occurs if I am in D or R.

What could be the possible cause? The vibration is not a lot by all
means, but it is definitely noticible. I did try a Chevron fuel
injector cleaning bottle but I don't think it made any differences.
I've recently did a 60k maintenance at the dealer. I do not feel a
lack of power from the engine.

Thanks.

Raymond

4cyl toyota's are noted for this, a lot of fwd cars experience this to some
extent as the p/s rack is mounted on the engine subframe and some normal
vibration can be transmitted up the coulumn. Question is this is a new
problem, right? If this is a vibration, not a rough engine, like a miss
fire, you might want to have the engine and trans mounts checked for
cracking or deteroration.
> wrote in message
...
>
> Hi, I have a 99 maxima (65k mile) that I've kept in fairly good
> condition. Recently I've noticed that while idling (after the engine
> has warmed up), the steering wheel vibrates slightly. I checked the
> engine idle speed and it is between 600-700, and according to Hay's
> repair manual, this is within spec.
>
> When I turn on the AC, the RPM increases slightly during idle and the
> steering wheel no longer vibrates, however, I do sense vibration under
> my seats. Once I turn off the AC, the vibration returns to the
> sheering wheel.
>
> When I am driving, it is fine. When I am idle, the shaking stops once
> I shift to Neutral. It only occurs if I am in D or R.
>
> What could be the possible cause? The vibration is not a lot by all
> means, but it is definitely noticible. I did try a Chevron fuel
> injector cleaning bottle but I don't think it made any differences.
> I've recently did a 60k maintenance at the dealer. I do not feel a
> lack of power from the engine.
>
> Thanks.
>
> Raymond




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writes:

> Hi, I have a 99 maxima (65k mile) that I've kept in fairly good
> condition. Recently I've noticed that while idling (after the engine
> has warmed up), the steering wheel vibrates slightly. I checked the
> engine idle speed and it is between 600-700, and according to Hay's
> repair manual, this is within spec.
>
> When I turn on the AC, the RPM increases slightly during idle and the
> steering wheel no longer vibrates, however, I do sense vibration under
> my seats. Once I turn off the AC, the vibration returns to the
> sheering wheel.
>
> When I am driving, it is fine. When I am idle, the shaking stops once
> I shift to Neutral. It only occurs if I am in D or R.
>
> What could be the possible cause? The vibration is not a lot by all
> means, but it is definitely noticible. I did try a Chevron fuel
> injector cleaning bottle but I don't think it made any differences.
> I've recently did a 60k maintenance at the dealer. I do not feel a
> lack of power from the engine.

Well, this is the sort of problem that gives development engineers
gray hair. The original U.S. Escort had, not long before launch, a
steering wheel vibration of half an inch in amplitude at idle! It
turned out to be a combination of engine mount design, the mass and
stiffness of the steering wheel/column assembly, and structural
vibration modes in the front end. It was dealt with by switching to a
steel front bumper (from aluminum) and using that as a tuned-mass
vibration absorber. But only in the automatic-transmission cars; the
manuals were immune to the problem, as the loads at idle were slightly
different. The '85-1/2 had a new engine mount system, redesigned front
structure, and the radiator mounted on rubber as a tuned-mass
absorber. Kind of a belt-and-suspenders approach to the problem.

Anyway, if this vibration is new, something has changed. I concur with
the other poster that you might want to start replacing engine mounts,
subframe bushings, and the like. After all, it's unlikely that the
metal structure of your car has changed, and much more likely that
rubber has gotten harder or is getting weaker. Oh, and if the radiator
is on rubber mounts, check those, too .

--
-Stephen H. Westin Any information or opinions in this message are
mine: they do not represent the position of Cornell University or any
of its sponsors.

In rec.autos.tech Stephen H. Westin > wrote:

> Anyway, if this vibration is new, something has changed. I concur with
> the other poster that you might want to start replacing engine mounts,
> subframe bushings, and the like. After all, it's unlikely that the
> metal structure of your car has changed, and much more likely that
> rubber has gotten harder or is getting weaker. Oh, and if the radiator
> is on rubber mounts, check those, too .

Hi, thanks for the reply...

The vibration is relatively new. The degree is not severe, as I've
asked the dealer to check for it when I did an alignment and they
claim they can't reproduce it. But I suspect they did not spend too
much time on it, because it only occurs once the engine warms up.

Well, I do not know how to check or replace engine mounts, is it hard?
(I am just comfortable opening the hood and check fluid levels, maybe
if I really want to do it, replace engine oil and break pads). I did
look at the engine from the top and nothing obvious seems lose.

So I guess I need to find a mechanic (dealer?) that I can trust to
take a look at this. Anyone know of any in the SF Bay Area?

Thanks.

Raymond

In rec.autos.misc David J and Lynne J Shepherd > wrote:

> 4cyl toyota's are noted for this, a lot of fwd cars experience this to some
> extent as the p/s rack is mounted on the engine subframe and some normal
> vibration can be transmitted up the coulumn. Question is this is a new
> problem, right? If this is a vibration, not a rough engine, like a miss
> fire, you might want to have the engine and trans mounts checked for
> cracking or deteroration.

I am not a car expert, what is the sympton of a rough engine? I do not
notice any unusual noise from the engine, only that it doesn't seem to
be as smooth at idle.

If it's the engine mount that's lose, how come the vibration goes away
as soon as I hit the gas padel? Wouldn't it be more?

The Haye's Repair manual mention things like vacume leakage, fuel
pressure, etc... could those be causing this problem? (maybe those
have more severe symptons, but I am not really sure about those...)

Thanks.

Raymond

writes:

> In rec.autos.misc David J and Lynne J Shepherd > wrote:
>
> > 4cyl toyota's are noted for this, a lot of fwd cars experience this to some
> > extent as the p/s rack is mounted on the engine subframe and some normal
> > vibration can be transmitted up the coulumn. Question is this is a new
> > problem, right? If this is a vibration, not a rough engine, like a miss
> > fire, you might want to have the engine and trans mounts checked for
> > cracking or deteroration.
>
> I am not a car expert, what is the sympton of a rough engine? I do not
> notice any unusual noise from the engine, only that it doesn't seem to
> be as smooth at idle.
>
> If it's the engine mount that's lose, how come the vibration goes away
> as soon as I hit the gas padel? Wouldn't it be more?

No, it wouldn't, thanks to the wonders of mechanical dynamics. To
simplify outrageously, you have a tuning fork. If the natural
vibration of the engine coincides with the resonant frequency of the
tuning fork, it will vibrate. Any other frequency won't stimulate the
vibration. This is especially true if it's an inline 4, which has an
inherent imbalance at a frequency twice the RPM. There's a lot of
careful tuning to isolate you from that vibration, and we're guessing
than the tuning has changed so that the vibration is stimulating the
steering wheel.

> The Haye's Repair manual mention things like vacume leakage, fuel
> pressure, etc... could those be causing this problem? (maybe those
> have more severe symptons, but I am not really sure about those...)

Well, that all falls under "rough engine". I don't know how to tell
you if your engine is idling normally; I think you need to find a good
mechanic who knows your model of cars. Out here in the wilderness,
there are eccentrics that specialize in SAABs, Subarus, Volvo, and the
like; you need to find the equivalent in the Bay area for your car.

In answer to your other query, probably the only way to diagnose
engine mounts is to replace them and see what happens. If any of them
has obviously deteriorated, then try replacing that one first. Doing,
this, of course, is moderately involved, as you will have to support
the engine's weight with a hoist or something, not to mention what you
might have to remove just to get to the mounts. You probably have 3-5
mounts; one may involve a strut connecting the engine to the firewall,
and that one might be in the form of a hydraulic damper that looks
like a small shock absorber. If so, that damper might be worn. Again,
a good mechanic who listens both to you and to the car would help.

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.

On Tue, 20 Apr 2004 wrote:

> So I guess I need to find a mechanic (dealer?) that I can trust to
> take a look at this. Anyone know of any in the SF Bay Area?

Yarnell's Toyota/Datsun in Mountain View is a bit of a drive from SF but I
found them to be excellent on my old celica. If you don't mind a bit
of a drive give them a call and see if "Datsun" now officially means
Nissan, since they were definitely specialists in a few makes including
toyota and I don't think they worked on some brands, notably domestics.

Dave