Again Oil in J-Tube after replacing AOS

[JP986]

A few weeks ago I replaced my Oil separator with the new updated version on my 2.5L Boxster with 90k on it (proud daily driver). I also replaced the J-Tube (thanks to Mike Focke!), but afterwards the car was still running bad - black smoke (especially at higher rpm's) and when I stop to accalerate (driving with constant speed) the engine is stuttering. At my service station they replaced the sort of EGR valve (cut-off valve), cause they thought it is a secondary air problem - it didn't changed a thing.

Yesterday I wanted to clean the throttle body and I noticed the new J-Tube from the AOS is full with oil again!!! Does anyone has an idea what's wrong with my car?

I still have engine failure codes from all O2 sensors and a lot of missfires on both banks. I think my entire system runs too lean and that's why the engine get's sometimes too much fuel injected (black smoke). I checked the car for secondary air leakages and already replaced the MAF....

1998 Boxster, 2.5L, 5-Speed, 90.000 miles

[wvicary]

It's normal to have some oil in the J tube. Don't drive the car if the check engine light is flashing. Can you list the engine codes. To my knowledge your car doesn't have a EGR valve.... maybe best to start by finding another garage to have a look at it.

[JP986]

It's normal to have some oil in the J tube. Don't drive the car if the check engine light is flashing. Can you list the engine codes. To my knowledge your car doesn't have a EGR valve.... maybe best to start by finding another garage to have a look at it.

I know- it was not the EGR- they replaced the Air Pump Valve (993.113.250.03).

To find another garage here in Michigan is not so easy - most of them have not really experience with the Boxster, so they just start to replace one part after the other... To replace the entire engine would be way cheaper I guess.

Here is my "best of" failure codes:

27 OXS sensing range 1, Cyl 1-3, P1123 or P1124

34 OXS sensing range 2, Cyl 4-6, P1129 or P1130

10 OXS Sensor before cat cyl 1-3, P0130, 0134, 0131, 0132 *

18 OXS Sensor before cat cyl 4-6, P0150, 0154, 0151, 0152 *

26 OXS sensing range 2, cyl 1-3. *

55 Misfire Cyl 6 emission related, P1318

53 Misfire Cyl 4 emission related, P1316 *

54 Misfire Cyl 5 emission related, P1317 *

62 Misfire Cyl 5 emission related, P1319 *

[Loren]

What are the current code(s)?

[JP986]

The codes marked with a * returned.

I just checked all my documents and when I had the trouble with my MAF I had similar codes. I will clean my MAF tomorrow- maybe that helps, allthough I don't think so it is just 3 months old and at that time I never had black smoke...

[Loren]

That would say that the mixture on cylinders 1-3 is too rich (and the DME can not lean it enough) and your misfires and your O2 sensor on the cylinder 4-6 side is shorted (or reading a very high voltage).

I would find a shop with some good OBD II software and have them read the MAF air flow and TRA\FRA values so you can really see what is going on.

[JP986]

cleaned the MAF today and afterwards cleared the computer. Nothing changed - CEL came back on, engine is stuttering and black smoke comes after 3000rpms. Is there a way to check my O2 sensors? How do I know that my cat is still working?

Edited September 8, 2007 by JP986

[JP986]

I replaced the two pre-cat oxygen sensors. The car runs perfect now- no gas smell, engine stuttering or black smoke anymore. After 40 miles the engine check light came back on (P0130), I assume it is due to the dirt and carb which is still in the engine. I added some Techron (Chevron) engine cleaner to the fuel and fired the engine with high rpms on the highway to get it hot and clean- seems to work! So far (140miles) the light didn't came back on.