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Old 07-28-2014, 01:22 PM   #1
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Throttle Response and Failing AOS

Last week I had some time to get into my engine for a few things. I had the left and right plenums open and noticed that they are wet with oil and the pooling in the right maybe up to 1-2mm depth. I would assume that the AOS is on its way out from this.....especially when I was I there attending to an oil filler tube leak. Oddly, last time I checked I had very little suction on the oil filler cap. No smoke. The thing seems to be stealthily failing..

Would this situation affect proper throttle response from 3-4K ? I would think it would if you trying to combust too much oil/vapour. I have been chasing this problem and I think this maybe it.

Is there currently a better motorsports AOS that can go in a 2000 S ?

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Old 07-28-2014, 03:24 PM   #2
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Originally Posted by jaykay View Post
Last week I had some time to get into my engine for a few things. I had the left and right plenums open and noticed that they are wet with oil and the pooling in the right maybe up to 1-2mm depth. I would assume that the AOS is on its way out from this.....especially when I was I there attending to an oil filler tube leak. Oddly, last time I checked I had very little suction on the oil filler cap. No smoke. The things seems to be stealthily failing..

Would this situation affect proper throttle response from 3-4K ? I would think it would if you trying to combust too much oil/vapour. I have been chasing this problem and I think this maybe it.

Is there currently a better motorsports AOS that can go in a 2000 S ?
No MS AOS is made for the 2003 up style AOS engines.

AOS diaphram degrades & begins to tear. Oil in cylinders begins to foul the spark-plugs.

Check your plugs starting on Passenger side.
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Old 07-28-2014, 06:48 PM   #3
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Hmm. A bit of a poser. I have the same year. If there's not a lot of vacuum at the oil filler, I don't think it's the AOS. Ive had lots of oil when i took off the plenums, so I don't think that's the problem.

Any codes? Get back to me if you have a dura metric, there are some values you can look at to check for common problems.
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Old 07-28-2014, 06:56 PM   #4
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No cel and no codes stored on the last durametric (enthusiast version) scan. I would have thought the wet plenums would mean improper air oil separation.

Please let me know what values to check....maybe MAF and O2 just to start ....would need to know the acceptable ranges
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Old 07-28-2014, 07:02 PM   #5
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Quote:
Originally Posted by BYprodriver View Post
No MS AOS is made for the 2003 up style AOS engines.

AOS diaphram degrades & begins to tear. Oil in cylinders begins to foul the spark-plugs.

Check your plugs starting on Passenger side.
Okay I had a feeling I was out of luck with my year...will pull a plug

Thanks !
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Old 07-30-2014, 09:21 PM   #6
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Okay I have just finished about three hours running time: highway, country and gridlock......yah TO has it really bad right now

I pulled the oil filler cap to check for suction and there is enough to hold the spring loaded oil filler funnel until I knocked it against its upward stop....so perhaps approaching the suction force of an old worn out vacum cleaner and I can get a hissing noise happening by hold the cap close. Is this normal suction? I would say no myself...

Also covering and uncovering the the filler funnel a few times disrupts the idle of the engine and one can feel the engine react to the vacum change. Again, not knowing the inner workings of the AOS, it feels like the AOS is packing up. Anyway it's odd that most only see the smoke screen and then they know

How would this AOS condition affect throttle response??
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Old 07-31-2014, 03:33 PM   #7
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Oil Separator (High Performance Version)
- Boxster S Special Edition Convertible (2004) Note: Also use (Qty.) (1) 996 107 947 00 line.
- Boxster and Boxster S Convertible (2000-04) Note: Also use (Qty.) (1) 996 107 947 00 line.
Brand:
[More Info]
Rating: Part Number: 996-107-926-00-M100

It would appear that a high performance AOS is available for from Pelican and if you check it out the listing seems to indicate that it will fit the above. Is this correct??
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Old 08-05-2014, 08:27 AM   #8
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The performance AOS *only* works on the Boxster 03 and up engines. It has to do with the oil return tube Porsche installs in the engine. The earlier 97-02 blocks? the AOS has a penis that goes into the block. 03 and up is completely different.
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Old 08-05-2014, 12:53 PM   #9
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Okay, thanks! Now I know for sure the listing put some doubt in me. Errrr em.... If the penis does not fit it usually means things are not going to work as they should

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