Whistle at idle - vacuum leak, induction side

[RichieRoo]

Hi all!

Our little Yaris is a '99 1litre.

For the past few weeks it has developed a whistle when the car
is stationary and idling. The whistle disappears at higher revs.

The car idles a little slow and not perfectly smoothly - indicating
an air leak on the induction side.

My problem is that I can't locate the leak. I've checked all the
vacuum pipes whilst the engine is running and pushing/pulling
the plastic inlet manifold and throttle body doesn't alter the pitch
of the whistle, let alone stop it.

Does anyone know where they 'normally' leak?

Any advice warmly received.

Cheers

Rich

[saplaymate]

bad advice, vacuum leaks suck.

Spray some carb cleaner around the hoses and intake track joints, if the idle picks up a little you found your leak.

[supmet]

Originally Posted by saplaymate

bad advice, vacuum leaks suck.

Spray some carb cleaner around the hoses and intake track joints, if the idle picks up a little you found your leak.

Carb cleaner on hoses? I think you found your leak because the carb cleaner ate a hole in your hose, or caused it to become so brittle you cracked it.

[RichieRoo]

Well, everyone seems to be thinking along the same lines... some kind of liquid.

I might try a little WD40 or silicon spray perhaps that won't damage anything
back there. I should only need a little to identify it - I reckon the liquid will
momentarily block the leak a stop the whistle for a split second allowing me
to narrow my search area.

I'll give it a go and report back. Thanks for the ideas.

[Shroomster]

you ever thought since it doesn't change when you move the plastic that it might be the butterfly valve/throttle body inlets for recirc = carbon buildup?

[2009Toyotoad]

Unfortunately, unless you changed hoses in the past, at 10 years old, all the hoses and softparts are suspect. Start with the cheap one and work your way up.

[Shroomster]

update?

[RichieRoo]

Cheers for the posts... I will update as soon as I have a chance to look into it.
The car is needed every day by my other half who is a care worker so the
opportunities to have it off the road are few and far between.

But I promise as soon as I take a look, I'll post with photos.

[RichieRoo]

Ok, as promised, here's an update:

Today I tried spraying some WD40 around the parts which could be leaking air,
the whistle was constant so we decided to strip the inlet side.

Took the throttle body off, all the pipes and the inlet manifold. Visually it all
looked perfect. All the rubber seals looked like new.

I applied some gasket sealant to the manifold gasket before reassembly,
just for good measure.




The throttle body and butterfly were both pretty clean, but I went over them
with carb cleaner and the came up shiny.

Reassembled it all... Whistle still there and engine still rough on idle.
See video here.

Initially, from cold the car runs fine, but then as it warms up an the revs gently
fall to a normal/warm setting the car begins to whistle, clatters a little and idle
poorly (as seen in the video).

So I'm now stumped. Any ideas?

[GeneW]

Originally Posted by RichieRoo

Well, everyone seems to be thinking along the same lines... some kind of liquid.

I might try a little WD40 or silicon spray perhaps that won't damage anything
back there. I should only need a little to identify it - I reckon the liquid will
momentarily block the leak a stop the whistle for a split second allowing me
to narrow my search area.

I'll give it a go and report back. Thanks for the ideas.

I'd go with Propane or MAPP gas, from a torch. Just open up the valve and let the gas swirl around spots that you believe are leaking.

I used to work on vacuum systems using helium and a mass spectrometer coupled to the output of the pump. You would "squirt" a little bit of helium into various sample areas and watch the results.

A better way than using your ear is to use a tach or use feedback from the Oxygen sensor. I am not sure if a Scanguage will report Oxygen sensor readings but if so it's really simple to watch the O2 drop each time too much hydrocarbon gets in.

The best way to do this is to find "suspect" areas, section them off into sectors and expose each spot. For example, if you have a round fitting divide the area around it into quarters and expose each quartered area around the fitting for a few seconds.

Give the car about ten seconds or more between "exposure" to hydrocarbons to restore its equilibrium, especially if you're using RPMs instead of O2 readings.

Take notes of where you saw changes, then later re-test the areas in more detail. I would avoid cranking up the gas through unlit torch or slathering on fluid because you could find two leaks at the same time, which will confuse you.

I'd avoid anything with silicon - could poison your catalytic converter.

Gene

[GeneW]

Originally Posted by RichieRoo

Initially, from cold the car runs fine, but then as it warms up an the revs gently fall to a normal/warm setting the car begins to whistle, clatters a little and idle poorly (as seen in the video).

So I'm now stumped. Any ideas?

You have a Scanguage? Set one of the displays to engine temps (I believe it's FWt). There is also an "Open" and "closed" display, don't recall offhand where they might be.

See when the motor's idle changes.... I suspect that the motor is adjusting for a leaner mixture in closed loop and that you have "lean idle lope".

As for the sound, that could be from different places... you are sure that you cannot hear it over the "cold" idle?

Gene

[yaris-me]

When was the last time you check the plugs or did a tune up? Have you checked all the electrical wiring for the ignition? You have nothing to lose at this point.

[rpalai]

Hello. I have a 2008 mint 2-Dr Liftback with a 5-speed and the Blitz Supercharger system The car has been fantastic for the past several months, really ever since we got it in 10-08. Nice power with the Blitz blower and never any probs. Now, all of a sudden it keeps setting the CEL and giving me a DSTC P0171, which means "lean condition" detected. Additionally, I notice that whenever I come to a full stop, the idle RPM's drop way down and it wants to nearly stall, but instead it shudders for a second or 2 and re-adjusts the idl up to about 500 RPM's (I have a factory tach cluster in mine) and that is mostly when it sets the CEL. Not every time, but often. So, I believe I am having the same problems as the folks who reference a lean spot at idle. I am stumped. l can NOT find any vacuum leaks anywhere. Any other suggestions. I have a Scangauge II that I use to re-set the CEL in the car but still, it is a pain in the butt to have to keep re-setting the CEL all the time. It happens too often. Otherwise, the car sill runs GREAT and is a lot of fun to drive. Good economy even with the Bltz. PLEASE HELP ME WITH THIS CEL PROBLEM!!! Thanks. RKP

[bronsin]

Originally Posted by RichieRoo

Ok, as promised, here's an update:

Today I tried spraying some WD40 around the parts which could be leaking air,
the whistle was constant so we decided to strip the inlet side.

Took the throttle body off, all the pipes and the inlet manifold. Visually it all
looked perfect. All the rubber seals looked like new.

I applied some gasket sealant to the manifold gasket before reassembly,
just for good measure.




The throttle body and butterfly were both pretty clean, but I went over them
with carb cleaner and the came up shiny.

Reassembled it all... Whistle still there and engine still rough on idle.
See video here.

Initially, from cold the car runs fine, but then as it warms up an the revs gently
fall to a normal/warm setting the car begins to whistle, clatters a little and idle
poorly (as seen in the video).

So I'm now stumped. Any ideas?

My Suzuki DL1000 Vstrom whistled like a tea kettle once. It was the fuel pump straining against a semi blocked fuel filter.

[fmicle]

Originally Posted by rpalai

Hello. I have a 2008 mint 2-Dr Liftback with a 5-speed and the Blitz Supercharger system The car has been fantastic for the past several months, really ever since we got it in 10-08. Nice power with the Blitz blower and never any probs. Now, all of a sudden it keeps setting the CEL and giving me a DSTC P0171, which means "lean condition" detected. Additionally, I notice that whenever I come to a full stop, the idle RPM's drop way down and it wants to nearly stall, but instead it shudders for a second or 2 and re-adjusts the idl up to about 500 RPM's (I have a factory tach cluster in mine) and that is mostly when it sets the CEL. Not every time, but often. So, I believe I am having the same problems as the folks who reference a lean spot at idle. I am stumped. l can NOT find any vacuum leaks anywhere. Any other suggestions. I have a Scangauge II that I use to re-set the CEL in the car but still, it is a pain in the butt to have to keep re-setting the CEL all the time. It happens too often. Otherwise, the car sill runs GREAT and is a lot of fun to drive. Good economy even with the Bltz. PLEASE HELP ME WITH THIS CEL PROBLEM!!! Thanks. RKP

Just got a Blitz kit installed this weekend and I'm seeing the exact same behavior. Did you find the problem or a solution?

[stuck]

Guys any update ? I also got the same issue

[joe68]

Maybe the IAC needs cleaned

Does it sound like this?

http://www.youtube.com/watch?v=yldykQZd2S8

[Rattlesnake]

Originally Posted by RichieRoo

Hi all!

Our little Yaris is a '99 1litre.

For the past few weeks it has developed a whistle when the car
is stationary and idling. The whistle disappears at higher revs.

The car idles a little slow and not perfectly smoothly - indicating
an air leak on the induction side.

My problem is that I can't locate the leak. I've checked all the
vacuum pipes whilst the engine is running and pushing/pulling
the plastic inlet manifold and throttle body doesn't alter the pitch
of the whistle, let alone stop it.

Does anyone know where they 'normally' leak?

Any advice warmly received.

Cheers

Rich

Hi rich, did you ever fix this. Crazy enough I have exactly the same problem at the moment on my identical Yaris lol