Ticking Noise?

[baby721]

Hi Everyone!

I have had my 08 Highlander for about a week -- it is a Sport - 4x4. So far, no real complaints. However, one thing I was noticing was that when the engine was cold, when I hit the gas, there was a ticking/tapping sound. Once the car has been running for about 5 minutes, the sound seems to diminish. Anyone have the same experience or have any thoughts on where the noise may be coming from? Thanks

[summerwind]

You are hearing the injectors.
It is "normal" and like you said goes away when the engine warms up

[ktmd]

Yes, mine does the same thing. It is normal.

[jwall]

I guess we can all rest assured that the ticking noise is "normal" and they all do it, but I'm a little skeptical.
I've owned many FI cars and have never heard that kind of racket from the injectors.

Just to clarify, the noise happens only when cold (like a cold start) and is most noisy when in gear, under load and given a little gas. The colder it is, the noisier it is, am I correct?

I know I'm new here and I'm not trying to be a jerk, but who told you summerwind that is was the injectors? A Toyota technician or dealer?

EDIT:
I just talked to my dealer's service department and I barely got through describing the problem before he said it's valve train noise and is normal and they all do it.
so, FWIW

[summerwind]

Originally Posted by jwall

I
I know I'm new here and I'm not trying to be a jerk, but who told you summerwind that is was the injectors? A Toyota technician or dealer?


so, FWIW

A Toyota Tech and also it has been discussed on ToyotaNation before.

you can do a Google search on "fuel injector noise" for more discussions.

With the engine mounted sideways, the fuel injector rail for one bank is along the firewall. On vehicles with engines mounted front to back the injectors are away from the firewall. Don't know if this influences engine noise getting transmitted into the passenger cabin or not but it would seem to be one explaination.

If you lift off the plastic cover from the top of the engine you will see Toyota has sound deadening material on the underside of it. It helps some.

What ever answer you get regarding the source of the noise you will get the same answer "it's normal"

[jwall]

summerwind,
Thanks for the reply. You are so right about "normal" as being the standard explanation.
What you say certainly makes sense as does my dealer's.

I just want to be sure no detrimental engine damage is going on. It's weird to me that I only really hear it under load, not at idle so much, but taking off from a stop and it does diminish after a few minutes.

I probably will take it to the dealer, just to document it.

Thanks again.

[jwall]

summerwind,
I did the search and kind of wish I hadn't.
I ran into talk of piston slap in the Tundras:

"Ticking when cold? Could be the fuel injector solenoids (common - there was a sound proofing fix for this described way back before the system crash) or just the typical cold clearance noises from the valve train of a 32 valve dual overhead cam engine with direct cam-on- valve lifter arrangment (via shim and bucket "lifters" - no hydraulic lifter to quiet the noise).

Is the noise a ticking or more of a light knocking? Does it occur when temperatures are really cold (below freezing)? Does the noise increase when you put the transmission in gear and put a load on the engine? Does it go away after a couple of minutes? If yes to all of the above, this is likely piston slap noise. A common concern/annoyance among many Tundra/Sequioa 4.7L V8 owners."

What do you think?

[Bandito]

It's normal, so don't worry about it. Besides, you have 5 years to get it fixed if something goes wrong, no?

[kraky]

MY '06 Avalon does the same thing. It sounds a little bit like a GM diesel for the first few miles and then quiets down. Even at 70 degrees it's noticable. I tend to think if it was injectors you'd hear it all the time...can't figure what warming the engine would do to change that. I think it's valve train noise on the lifters but am not the least bit worried. Like said above....there's plenty of warranty to fix it and if it is a real problem it will become known here on the chat rooms.

[summerwind]

Here is some info from the "Gospel from Toyota" shop manual

This engine uses roller No.1 valve rocker arm sub-assemblies with built-in needle bearings.
This reduces the friction that occurs between the cams and the roller No.1 valve rocker arm sub-assemblies that push
the valves down, thus improving fuel economy.
Hydraulic valve lash adjuster assemblies, which maintain a constant zero valve clearance through the use
of oil pressure and spring force, are used.
Both the engine oil that is supplied by the cylinder head sub-assembly and the built-in spring actuate the
hydraulic valve lash adjuster assembly. The oil pressure and the spring force that act on the plunger push
the roller No.1 valve rocker arm sub-assembly against the cam, in order to adjust the clearance between
the valve stem and the roller No.1 valve rocker arm sub-assembly. This prevents the generation of noise
during the opening and closing of the valves. As a result, engine noise is reduced.
SFI System
The L-type SFI (Sequential Multiport Fuel Injection) system directly detects the intake air mass using a
hot-wire type mass air flow meter.
An independent injection system (in which fuel is injected once into each intake port for each two
revolutions of the crankshaft) is used.
There are two (synchronous and non-synchronous) injections:
a) Synchronous injection, in which injection always occurs at the same timing relative to the firing order.
b) The non-synchronous injection in which injection is effected regardless of the crankshaft angle.
Furthermore, to protect the engine and achieve lower fuel consumption, the system uses a fuel cutoff in
which the injection of fuel may be stopped temporarily in accordance with the driving conditions.
This system performs group injection when the engine coolant temperature is extremely low and the
engine is operating at a low speed.

Speculating here...The text I highlighted in bold may be what we are hearing. All the injectors operating in "group mode" (more fuel required when cold)

[jwall]

Thanks, summerwind.
Pretty hard to argue with the "book"

As mentioned, there is plenty of time and warranty to sort it out if it becomes a problem.

Thanks all.

[summerwind]

Did you notice the comment

Furthermore, to protect the engine and achieve lower fuel consumption, the system uses a fuel cutoff in which the injection of fuel may be stopped temporarily in accordance with the driving conditions

I wonder if this is an attempt to do the Honda Variable Cylinder Management (cuts out certain cylinders when cruising at highway speeds) thing without getting the patent violation flag waved..

The thing that didn't turn me on with the Honda system is it uses "white noise" through the radio to mask the noise from the engine when cylinders are cut out.

The Accord Sedan’s V-6 features the latest generation of Variable Cylinder Management™ (VCM®) technology.
This system can activate and deactivate the engine’s cylinders as needed to meet the demands of both acceleration and fuel savings.
When maximum torque is required, all six cylinders are firing.
During steady cruising speeds , VCM shuts down one bank of cylinders.
In this mode, the audio system’s Active Noise Cancellation™ (ANC) function generates out-of-phase sound waves
to cancel out any undesirable noise that may be due to the harmonics of 3-cylinder operation.
As cruising speed increases the engine moves to a 4-cylinder mode for extra cruising power.
To help keep engine vibration from reaching the cabin in every mode,
active engine mounts automatically adjust their firmness to help absorb energy.
The transition between the three operating modes is completely seamless and goes unnoticedby the Accord’s passengers.

Guess I can't get the GM 8-6-4 engine out of my mind were they tried to do the same thing and it didn't last very long. Computer control of everything probably makes it possible now but this approach is a stretch for me.

[akira751]

I had to start up a row of cars to show a customer that its normal one time and then we went to my Camry and then back to his 05 Avalon and they have the same sound.

[jwall]

Originally Posted by summerwind

Did you notice the comment


Guess I can't get the GM 8-6-4 engine out of my mind were they tried to do the same thing and it didn't last very long. Computer control of everything probably makes it possible now but this approach is a stretch for me.

Yeah, and I've been told that on the GM engines, the few cylinders doing all the work looked really bad on tear down, though I've not seen it for myself.

The computer stuff is nice when it works, but when it doesn't...

It was -1 this morning and 25 in my garage and everything sounded 'OK', but had to have the heater on full blast. Maybe that's the answer, just kidding.

[summerwind]

Originally Posted by akira751

I had to start up a row of cars to show a customer that its normal one time and then we went to my Camry and then back to his 05 Avalon and they have the same sound.

Here is a link to a "suitable for framing" version of what I posted.
It contains the source info to what is on the Toyota Techical Info Systems site.

How the Injectors work