Whistle (whistling) sound at low throttle

[rprieto]

I noticed, while driving my 2002 986 S, 89K Miles, a whistling sound at low or easy throttle. Seems to be while in drive mode only. While at a light, or in any gear I can hear a whistle if I barely tap the throttle. Goes away if I am harder on the throttle. I only noticed this after replacing my MAF Sensor. Sound is more noticeable as I have not put back the fabric over the cover yet.

I had a P0102 and replaced the MAF Sensor from Sunset this week.

I think I still have a bad "new" MAF sensor as it ran immediately worse and threw.

-> P1133: Oxygen sensing adaptation, lower load range, bank 2

-> P1126: Oxygen sensing adaptation, lower load range, bank 1

I went back in to look around for an air leak (visual only) and noticed one of the air filter latches was not attached properly and I snapped it back on. Ran slightly better, much less stuttering, but and I am now getting the original P0102 code with the new MAF Sensor!

I am a new owner and had a pre-purchase inspection. One thing noted was Oil-Overfill.

Can that (overfill) be the cause and I am seeing a ripple effect? If so I will do an oil change (myself) and look for leaks (air) & such.

I am thinking I have 2 things going on, one still being a bad MAF sensor. I will try to isolate that this by tomorrow by disconnecting the sensor.

Looking ahead, is R&Ring the AOS a DIY and has that been documented here? If I drain off some of the OIL will that fix my AOS issue?

I've only find some bits of info here on the AOS. I am able to remove the oil cap with the engine on idle with no effort. When it is removed, I can hear it constantly "breathe" or suck air in.

Is there an fault isolation procedure for the AOS? Will a bad one throw any codes?

Frustrating beyond belief. I just wish I can simply drive. Big project going on and I only have late eves and the weekends.

Thanks in advance for your advice!

Edited December 5, 2008 by rprieto

[1schoir]

I noticed, while driving my 2002 986 S, 89K Miles, a whistling sound at low or easy throttle. Seems to be while in drive mode only. While at a light, or in any gear I can hear a whistle if I barely tap the throttle. Goes away if I am harder on the throttle. I only noticed this after replacing my MAF Sensor. Sound is more noticeable as I have not put back the fabric over the cover yet.

I had a P0102 and replaced the MAF Sensor from Sunset this week.

I think I still have a bad "new" MAF sensor as it ran immediately worse and threw.

-> P1133: Oxygen sensing adaptation, lower load range, bank 2

-> P1126: Oxygen sensing adaptation, lower load range, bank 1

I went back in to look around for an air leak (visual only) and noticed one of the air filter latches was not attached properly and I snapped it back on. Ran slightly better, much less stuttering, but and I am now getting the original P0102 code with the new MAF Sensor!

I am a new owner and had a pre-purchase inspection. One thing noted was Oil-Overfill.

Can that (overfill) be the cause and I am seeing a ripple effect? If so I will do an oil change (myself) and look for leaks (air) & such.

I am thinking I have 2 things going on, one still being a bad MAF sensor. I will try to isolate that this by tomorrow by disconnecting the sensor.

Looking ahead, is R&Ring the AOS a DIY and has that been documented here? If I drain off some of the OIL will that fix my AOS issue?

I've only find some bits of info here on the AOS. I am able to remove the oil cap with the engine on idle with no effort. When it is removed, I can hear it constantly "breathe" or suck air in.

Is there an fault isolation procedure for the AOS? Will a bad one throw any codes?

Frustrating beyond belief. I just wish I can simply drive. Big project going on and I only have late eves and the weekends.

Thanks in advance for your advice!

AOS replacement is a fairly straightforward DIY, with only slight difficulty in installing the lower clamp on the bellows. There are a number of step by step DIY's on AOS replacement, both on Renntech and on Mike Focke's Boxster Pages.

As to the whistling sound, take a look at this thread, where "RFM" confirms that it is a sign of a failing AOS if it occurs at low throttle:

http://www.renntech.org/forums/index.php?s...mp;#entry124739

Regards, Maurice.

[rprieto]

I noticed, while driving my 2002 986 S, 89K Miles, a whistling sound at low or easy throttle. Seems to be while in drive mode only. While at a light, or in any gear I can hear a whistle if I barely tap the throttle. Goes away if I am harder on the throttle. I only noticed this after replacing my MAF Sensor. Sound is more noticeable as I have not put back the fabric over the cover yet.

I had a P0102 and replaced the MAF Sensor from Sunset this week.

I think I still have a bad "new" MAF sensor as it ran immediately worse and threw.

-> P1133: Oxygen sensing adaptation, lower load range, bank 2

-> P1126: Oxygen sensing adaptation, lower load range, bank 1

I went back in to look around for an air leak (visual only) and noticed one of the air filter latches was not attached properly and I snapped it back on. Ran slightly better, much less stuttering, but and I am now getting the original P0102 code with the new MAF Sensor!

I am a new owner and had a pre-purchase inspection. One thing noted was Oil-Overfill.

Can that (overfill) be the cause and I am seeing a ripple effect? If so I will do an oil change (myself) and look for leaks (air) & such.

I am thinking I have 2 things going on, one still being a bad MAF sensor. I will try to isolate that this by tomorrow by disconnecting the sensor.

Looking ahead, is R&Ring the AOS a DIY and has that been documented here? If I drain off some of the OIL will that fix my AOS issue?

I've only find some bits of info here on the AOS. I am able to remove the oil cap with the engine on idle with no effort. When it is removed, I can hear it constantly "breathe" or suck air in.

Is there an fault isolation procedure for the AOS? Will a bad one throw any codes?

Frustrating beyond belief. I just wish I can simply drive. Big project going on and I only have late eves and the weekends.

Thanks in advance for your advice!

AOS replacement is a fairly straightforward DIY, with only slight difficulty in installing the lower clamp on the bellows. There are a number of step by step DIY's on AOS replacement, both on Renntech and on Mike Focke's Boxster Pages.

As to the whistling sound, take a look at this thread, where "RFM" confirms that it is a sign of a failing AOS if it occurs at low throttle:

http://www.renntech.org/forums/index.php?s...mp;#entry124739

Regards, Maurice.

I purchased the AOS today just in case as they close early. (Not yet installed as I am trying to isolate the problem.) My current AOS is the newer style. Q1: Do the new style AOS still go bad?

I drained about 1/2 qt of oil and I replaced the Air Filter. The new air filter fit much tighter than the old and very dirty one.

The car runs much better and there are no CELs. So... Q2: I am thinking there might have been an air leak around the filter. (Is that possible)? I've not taken it on the freeway yet so I'll see how that goes soon.

But.... the whistle is still there. Happens even in park and again just a tad on the throttle. With the top off the sound is coming from the throttle body are and not the AOS side.

A3: Should I be looking into the throttle body?

[1schoir]

I purchased the AOS today just in case as they close early. (Not yet installed as I am trying to isolate the problem.) My current AOS is the newer style. Q1: Do the new style AOS still go bad?

I drained about 1/2 qt of oil and I replaced the Air Filter. The new air filter fit much tighter than the old and very dirty one.

The car runs much better and there are no CELs. So... Q2: I am thinking there might have been an air leak around the filter. (Is that possible)? I've not taken it on the freeway yet so I'll see how that goes soon.

But.... the whistle is still there. Happens even in park and again just a tad on the throttle. With the top off the sound is coming from the throttle body are and not the AOS side.

A3: Should I be looking into the throttle body?

The newer style AOS' still fail, just not as quickly and regularly as the older style ones.

Air leak around the filter is certainly possible if the housing is not securely fastened, etc...

There would be no harm in removing the plastic tube leading to the throttle body and taking a look there for any oil residue. That would help to confirm the bad AOS theory that the whistling might be indicating.

Any more codes?

Regards, Maurice.

[rprieto]

I purchased the AOS today just in case as they close early. (Not yet installed as I am trying to isolate the problem.) My current AOS is the newer style. Q1: Do the new style AOS still go bad?

I drained about 1/2 qt of oil and I replaced the Air Filter. The new air filter fit much tighter than the old and very dirty one.

The car runs much better and there are no CELs. So... Q2: I am thinking there might have been an air leak around the filter. (Is that possible)? I've not taken it on the freeway yet so I'll see how that goes soon.

But.... the whistle is still there. Happens even in park and again just a tad on the throttle. With the top off the sound is coming from the throttle body are and not the AOS side.

A3: Should I be looking into the throttle body?

The newer style AOS' still fail, just not as quickly and regularly as the older style ones.

Air leak around the filter is certainly possible if the housing is not securely fastened, etc...

There would be no harm in removing the plastic tube leading to the throttle body and taking a look there for any oil residue. That would help to confirm the bad AOS theory that the whistling might be indicating.

Any more codes?

Regards, Maurice.

Yes... P0102. I took it on the freeway for a nice run. Stuttered like crazy around 3500 rpm. This, of course, with the new MAF sensor! Came back, disconnected the MAF sensor and took it for another freeway run. Ran like a champ. Sunset Parts was closed today. So, I'm thinking the new MAF sensor is bad. What else could it be? Parked the car for another weekend.

[rprieto]

I purchased the AOS today just in case as they close early. (Not yet installed as I am trying to isolate the problem.) My current AOS is the newer style. Q1: Do the new style AOS still go bad?

I drained about 1/2 qt of oil and I replaced the Air Filter. The new air filter fit much tighter than the old and very dirty one.

The car runs much better and there are no CELs. So... Q2: I am thinking there might have been an air leak around the filter. (Is that possible)? I've not taken it on the freeway yet so I'll see how that goes soon.

But.... the whistle is still there. Happens even in park and again just a tad on the throttle. With the top off the sound is coming from the throttle body are and not the AOS side.

A3: Should I be looking into the throttle body?

The newer style AOS' still fail, just not as quickly and regularly as the older style ones.

Air leak around the filter is certainly possible if the housing is not securely fastened, etc...

There would be no harm in removing the plastic tube leading to the throttle body and taking a look there for any oil residue. That would help to confirm the bad AOS theory that the whistling might be indicating.

Any more codes?

Regards, Maurice.

How do I disconnect the thin rigid tube entering the large tube before the throttle body? I can take a photo to further describe as I have the 3.2 L version. The Bently Manual is useless for that area since their photos are of a different model. I was able to pull away the large tube from the throttle body but only 1/2 inch.

[1schoir]

How do I disconnect the thin rigid tube entering the large tube before the throttle body? I can take a photo to further describe as I have the 3.2 L version. The Bently Manual is useless for that area since their photos are of a different model. I was able to pull away the large tube from the throttle body but only 1/2 inch.

A photo would help.

If you are referring to the thin rigid "J" tube that is runs from the AOS (Air Oil Separator) to the throttle body large tube, you just have to squeeze the outer ring that circles near the end of that tube and then simultaneously pull back the tube and it should come apart.

Regards, Maurice.

[rprieto]

How do I disconnect the thin rigid tube entering the large tube before the throttle body? I can take a photo to further describe as I have the 3.2 L version. The Bently Manual is useless for that area since their photos are of a different model. I was able to pull away the large tube from the throttle body but only 1/2 inch.

A photo would help.

If you are referring to the thin rigid "J" tube that is runs from the AOS (Air Oil Separator) to the throttle body large tube, you just have to squeeze the outer ring that circles near the end of that tube and then simultaneously pull back the tube and it should come apart.

Regards, Maurice.

Here is a photo of my dirty engine compartment. Please let me know what folks use to clean it up.

My finger points to the rigid connection point I am having difficulty with. I don't want to break anything. It does not give. Is there a trick to disconnect it from the large tube entering the throttle body?

Edited December 10, 2008 by rprieto

[rprieto]

Can anyone help me with this? I see a good number of readers...

Is there a trick to disconnect the smaller rigid tube from the large tube entering the throttle body?

Appreciate the help...

Edited December 10, 2008 by rprieto

[1schoir]

Can anyone help me with this? I see a good number of readers...

Is there a trick to disconnect the smaller rigid tube from the large tube entering the throttle body?

Appreciate the help...

I don't have the same set up on my '97 Boxster, so I'm not sure how to disconnect that tube. :(

Regards, Maurice.