I replaced my intake with a EVOMS CAI this weekend and noticed that theres a fair bit of grime on my throttle body. I was pretty surprised! I've done some research and it sounds like this could be related to a failed AOS. Here's a picture I took. Does anybody think this would be a failed AOS? My car is an '05 with ~35k miles on it.

 

Looks like normal carbon build up to me. I don't think there's anything to worry about.

 

Do you observe a white plume of smoke during your first start up in the morning?

 

There haven't been any white plumes of smoke in the morning. At least none that are big enough for me to see from inside the car.

I was thinking to spray some carb cleaner on a lint free cloth and wipe this down without removing it. Any harm in doing so? Can I manually push the butterfly valve without causing issues?

 

You can remove the throttle body by removing those 4 torxs and disconnect the wires. I wouldn't move the valve.

If you didn't see any white smoke during morning start ups, then you probably still have a good Air Oil Separator.

 

Sounds good, thanks! I'll give this a go next weekend!

 

I always use CRC throttle body & intake cleaner. No it won't hurt to open the butterfly manually.I also use CRC MAF cleaner but you must remove the sensor for that.The throttle body is an easy to work on part. Good luck!

 

Looks fine. There are a few simple ways to test for a bad AOS.

With the engine running remove the oil filler cap. If you can't remove then the AOS is bad. If you remove it and the motor stalls there is a chance the AOS is bad also, RPMs dropping a little is fine. Put your hand over the filler neck, there should be slight vacuum, if there is a strong vacuum then new AOS time.

If you ever have the motor dropped out for other work, get the AOS changed, it's so much easier with the motor out.

 

Words to live by: "If it ain't broke........." Just sayin.

 

I like to think myself of "preventive maintenance"...

 

You guys worry too much about benign stuff

 

You mean like a benign tumor? I'd still have it removed just in case it was going to turn into something worse. Maybe it's the same with preventative maintenance. Just sayin'.

 

"IT IS NOT A TUMOR"! name that quote

 

You think? Btw, tx again for pointing out my 911th post. Had a scotch w dinner to celebrate. It's the little things...

 

No worries, have been around cars my whole life and cleaning a throttle body with spray or removing it all together and soaking in cleaner is a piece of cake!