So I decided to try to adjust the throttel cable. Its been tangling up on a kink in the cable and makes the plates stick open a bit sometimes. Frustrating. So when I removed the TB, there was some pretty evident residual oil on the TB exit.

Maybe normal for some cars, BUT:

Not A turbo, this is a n/a car, so the turbo blowing oil in is not a possibility.
No emissions, oil gettign sucked in by mazda's Psuedo-PCV isn;t a possibility as the vent vents to a catchcan.
Last thing I think you guys might suggest is injection oil somehow making its way back through the intake... well, the car is pre-mix only, no oil injection anymore.

So where'd this oil come from? Any ideas?

 

WELL u r in a predicamint lol i was going to say it was your oil injection BUT apperantly it cant be. humm. maybe u have a small oil leak somewhere near your intake assembly and it getting sucked in through your filter. look down at the engin block and look for leaks. that happend to a friends of mines truck..... but it was a truck..... and it was a pos. but its worth a look right?

 

Just residual crap that's been in little passages in the TB for years from the EGR system, when it was functional, and is "bleeding" out a little...

My second guess for the day

 

I suppose both are possible. I actually have reworked the intake a bit so that one of the intake pipes large nipples gets split up to 5 smaller nipples that go straight to the fuel injector bleeds. I'm not sure how I'd get a suction on the fuel injector bleeds, as they themselves has suction on the opposite side of the nipple per the manifold... strange.

Nothing important I suppose.

 

I've had oil in my TB before also.... and my EGR is blocked off wayne

I woudln't pay it too much mind... unless you start noticing some oil lossage.

And I thought S5s don't have EGR...

 

Ooh ooh, I got it!!!

The purge valve...Routes **** to the intake from the charcoal canister every start-up, if the system's working right...

Whatcha think?

 

Wayne gets the 26 million penny check.

 

Yeah, that thing. Purge valve... Mazda-Pseudo-PCV :nipple capped off, Charcoal canister gone.

Otherwise woulda been good...

 

Dang! OK, I revert back to my first guess, then , lol...Time for snooze...

 

My guess is that up until fairly recently in the car's life it had a perfectly functional PCV system. Unless you happened to steam clean the inside surfaces of your intake system at the same time you fitted the catch can, what's there is the perfectly normal build-up of oil from the first 15-odd years of the car's life.