OILY Mass Air Sensor = Poor running + CEL's !! Check It Out!!

Hey everyone, I have been having some strange running problems with my car the last month or so and have started some threads over the last couple of weeks trying to get your help to figure it out. Before I get into the diagnosis and ultimately the cure of the problem I would like to thank everyone on the forum who has given me some good advice, especially Scott from Softronic who suggested something that led me to really figure out what was going on and figure this thing out. Basically about a month ago I destroyed the Fabspeed headers I had on my car for about 4 months(the catylist media broke down), of course I realized this because I started throwing CEL's and Fabspeed is working now to get me a new and improved set. After replacing the factory headers I was still getting CEL's, I have the Durametric software and would check the fault codes and rest the CEL warning but it would show up again with different fault codes after about 20-30 miles later, very confusing... Also I couldn't seem to get it to run beyond 6000 rpms, it would just die at that point. So this morning I decided to check everything in the engine compartment and removed the intake boot on the throttle body and I found a PUDDLE OF OIL in the intake pipe, this is the piece between the Mass Air Sensor and the throttle body. I further investigated toward the air filter and low and behold there was another puddle of oil directly below where the Mass Air Sensor (MAF) is mounted, this in CLOSE proximity to the air filter. I removed the short segment of intake that houses the MAF (clips to air cleaner housing) and could clearly see an oily film all over the sensor. I then cleaned the MAF and the associated electrical connections with a cleaner specifically designed for it made by CRC ( $6 at pep boys) and cleaned the oil out of the rest of the intake boots with carb cleaner and then reassembled everything. I took the car out for a drive and it is running BETTER THAN EVER!! with no CEL's after 40 miles!! I am amazed what a difference this has made. If anyone out there has not cleaned the MAF I highly recommend trying this as I have not only fixed the running problem but there is a noticable power improvement on top of it!! Of course the real issue here is the OIL INGESTION PROBLEM these engines inherently have. I don't recall anyone reporting oil byond the intake runner's but in this case oil has gotten close to the air filter housing and I don't even race my car other than a spirited sprit down the highway on occasion! So please, if you take her up to the redline occasionally clean your MAF at least once soon to see if there is a difference in you engine. I will be doing it everytime I change the air filter from now on (or sooner) try it you won't be sorry!! takes about an hour or so. Thanks again to everyone who has contributed their 2 cents towards my running problems! :cheers:

Wow. So now the oil ingestion problem is causing a more serious issue than merely smoke. And on a street-only car, too! I'm almost finished installing a MotorSports Vapor-Oil Separator in my car to solve this problem. I can report that there was oil EVERYWHERE in my intake system. There was oil in the plenum, in the rubber boots that connect the plenum to the intake manifolds, even on the cylinder head flanges where the intake manifold mounts. It's a mess. I haven't been to a track since March, but I have been AXing a lot. I'll check my mass flow sensor before I button everything back up. Thanks for the heads-up, intubator!

No problem! and thanks to you as well for chiming in on my other related posts with advice! I really am surprised at what an improvement this has made, hope it helps you as well!! :cheers:

Do you have a standard air filter or an oil based filter, like K&N ?

What I was wondering as well because oil should be be getting by the throttle body back down the intake tube and into the MAF sensor area. Despite a lot of oil ingestion in my engine before the Motorsport VOS was installed, I never had oil in those areas which would lead me to suspect some aftermarket air filter element was being used so I'm curious to the answer to this as well.

Thanx Intubator for the heads up.... In the near future, if anyone plans to clean the MAF, would they be able to kindly take some snaps and write a brief article for us novice folks please.....

Absolutely, i will write up an article, right now I'm a little ecstatic to have my car running well!! I am running a stock Mahle OEM filter for those who were wondering, no oiling involved and it has about 8000 miles on it now and "looks" clean. I am also running with the SRP which may or may not have an effect on oil running into the pre-throttle body intake areas, It does sit at a somewhat downward angle but I really don't remember the orientation of the stock unit exactly I think it was about the same. FYI, it was really easy to clean the MAF sensor, It actually sits in a about an 8" segment of intake tube where one end articulates with the air filter housing and two clips hold it together, the other end simply has a clamp that must be loosened. Disconnect the harness clip on the MAF sensor and the whole segment will lift out of the engine compartment. I tried to take the MAF out of the intake tube but it was just easier to take the tube out instead. Once I had access to the business end of the MAF sensor then it was simply a matter of spraying the cleaning solvent along the plate and associated areas about 4 shot squirts over a couple of minutes. I really hope alot of the members of the site catch this tip because I think that even with a little oil in the intake areas (especially some with more miles on the oil) the possiblity of oil based comtaminates that might become evaporated and the stick to cooler sensor related components is pretty high. Just consider how hot the intake areas probably get when the engine stops as well as the airflow under the cover and think what this does to any evaporative chemical in the oil! :cheers:

A side note as well, when I change the oil in my car which I've done 3 times now, I use only 8 quarts of Mobil 0-40 v.s. the 8.2 so I don't get close (or less close) to overfilling and exacerbating the ingestion problem. The car doesn't appear to use any oil either based on the standard "OIL check" test, the bars stay the same at least for about 6000 miles which is about the interval I use to do an oil change. :cheers:

Tracing the air intake should potentially identify the culprit. Where do you see the first evidence of oil in the intake? Is there some sort of PCV valve or engine breather hose that is feeding into the air intake?

One other person with a similar issue thought it might be related to his "de-snork". If you have not done that modification perhaps that will help put that to bed.

I have done the desnork but oil in the intake has nothing to do with a desnork problem unless I drive my car by an oil hose that is directed at the drivers side intake at high pressure. Sorry, a little sarcasm there, but seriously though I have had no problem with water getting into my air filter or any major particulate matter as a result of the desnork, I don't think I gained anything from doing it either. The only reason I checked the MAF sensor and discovered the oil puddles was because the engine would not rev beyond 6000 rpm's, Scott Slausen also suggested in an email that my running problems could be related to the MAF sensor as well. My theory is that the film was heavy enough so that it could not detect the increase in air flow at the higher rpms despite the fact the throttle plate was wide open. From what I understand the MAF sensor is heated and as air flows over, around, etc.. it cools and can calculate the amount of fuel needed to inject to create an optimal combustion cycle based on the engine load. I would imagine that any dirt, oil, bubble gum or anything on that sensor plate will not allow it to function properly, essentially fooling it into thinking there is less airflow than there actually is thus causing a lean combustion mixture. So guys get out there and buy a can of cleaner and optimize your MAF sensor!! :banana: Let me know how it goes!

I just wanted to clarify on the "Motorsports VOS" . This is not a motorsports part and is a PAG release that goes originally back to the 2003 Boxster and was originally released in late 2003. The separator basically deals with the ingestion problem from bank 2 or 4-6 of the Boxster . Porsche has never officially explained this or offered specifics however I will quickly. This bank in its design was OK when installed in the 996 variant config. What happened is when the engine is now reversed in the Cayman or Boxster on increased g turns the oil goes up the case wall. This is also the galley for the timing chain and cylinder head forward. The oil goes directly up the ramp with the timing chain and to the top of the 4-6 cylinder head. A combined effort of the chain rotation, Heavy G's and throttle plate closer on a turn allows the oil to be suct up from the 4-6 breather. The bank 1 or 1-3 cylinders draw from a more centralized location and thus would not allow this ramping effect in the 996 ,997 or the 986 ,987. Other items that would offer the same effect to the alt separator would be eliminating the 4-6 breather or changing the system to a PCV system that is pre TB plate. However for the 987 the alt oil sep. is an easy and simple fix. Best, Scott SLauson

Just as a side note, my car has never smoked that I know of, even after sitting for 2 weeks! I hope you guys/ gals check this fix out I really think it may improve the performance in some cars which don't have any obvious running problems, especially those with higher mileage, I now have about 20000 K on mine. If the thing (MAF) hadn't gotten so gummed up that my engine wouldn't rev beyond 6000 rpms then I probably would not have had any reason to open up the intake system and discover the oil there.

I believe PCA-TECH is of the opinion that either your backfires in your motor from disintegrating cats caused you to get oil that far back up the intake or a very dirty filter.

This yes can happen from a dirty filter or definitely from a quote free flow filter after cleaning and oily. The next time anyone has the operant unity to look at one of these filters hold it up to the light and let me know what you see . A filmed MAF can also happen from plugged or deteriorating cat's and also from just changing your air filter. Blowing dust out of the air filter housing when changing the filter is another known problem. In any case Intubator gave a very good tip on cleaning the MAF and it does work. This can save you a good amount of money cleaning it first before buying one.

I’m glad I found this thread. I had a CEL that would come and go away after a while. After a couple of weeks it never went away. Then just before the weekend, the engine would die after starting and just reving the engine. A quick call to TPC and Tom had me first reset the throttle position sensor. When that didn’t work he said it was the mass air flow sensor. I got a can of the CRC mass air cleaner, followed the thread, and the car is up and running again. I did check with the dealer and they said the MAF would be covered under warranty, even with the turbo, if it wasn’t broken. If it was, it would have cost over $400 just for the part. Thanks for the write-up Intubator!

Sorry to resurect an old thread, but I am having problems clipping the 2 clips back onto the MAF tube, anyone have a trick to do this? My hands are full of small cuts trying to get this bad boy back on. Thanks!

I clean the MAF every time I change the oil (which is much more frequently than the book because of my turbo). The first indication I saw was a slightly stumbly idle. I cleaned the MAF and the idle smoothed out. I just made it part of my recurring maintenance routine.

Did you completely remove the intake tube that the MAF is attached to or just removed the sensor? I can't seem to get enough clearance to set the clips back in

See this article by, guess who, Intubator http://www.planet-9.com/planet-9-articles/40925-cleaning-mass-air-flow-sensor.html

Thanks Kenny, that is the article I'm using to do the job at the moment, but just running into a little extra trouble i guess. Haven't done this kind of job before so I'm just looking for a little extra instruction so I don't break anything lol

I do the procedure a little differently. I disconnect the hose that goes to the plenum (to the turbo, in my case), then disconnect the housing from the air filter box. That frees it enough that I can disconnect the electrical plug with it in my hand. On the reinstall, I install the air filter box end first. That lets me twist it and roll it to get the o-ring to seat fully. Like you, I have bloodied my hands and offered my sweet car profane encouragement and very profane criticism for her unwillingness to go back together easily, but I believe extreme difficulty with the clips is due to me not fully seating the MAF into the air box. [Yes, cars are female because, when it doesn't work correctly, it is your fault.] Then I install the plug and finally the exit hose. When I clean the sensor, I am not stingy with the fluid and I wet it and blow it with compressed air three or four times. The first spray is a soaking spray and I let it soak for 30 seconds or so to dissolve any deposits on the wire. The second spray is a washing sprays that gets blown off after 3 to 5 sec and the third spray gets blown off immediately. I take care not to get the air nozzle too close. The last thing I want to do is stretch that wire and change its diameter which would screw up the resistance of the wire and therefore the mass air flow calculation. I figure that the air velocity at red line RPM is about 70 mph, so air velocity less than that is obviously okay. I also clean the flow screen with the MAF cleaner. I hope that helps

Thanks kenny and others for your help! I was able to mount the MAF back on by using your info. I disconnected the accordion "elbow" on the side closest to the MAF tube instead of the throttle body side, so i did as you suggested and it gave me the wiggle room i needed to set both clips in. Thanks again! =)

I thought I would add to this discussion, seeing as the air-oil separator (AOS) recently failed in my 2006 Boxster S . I added some comments to the fine article detailing how to remove and replace the MAF housing, sensor, and related parts. After I replaced the AOS, the first time I started the car I still had the archetypal plume of bluish smoke pouring out of the exhaust. After idling the car for about 10 minutes, I took it on a 30 minute run to thoroughly heat up the engine up. The next two times I started the car only a small puff of blue smoke left the exhaust, and since then the car has started in its typical smoke-free manner. Two days later, however, I noticed that the car stumbled severely when I accelerated. I therefore decided to see if oil from the failed AOS had made it to the MAF sensor. After extracting the MAF housing, I found the that accordian tube that connects the MAF housing to the throttle body, the MAF housing, and even the beginning section of the air box closest to the MAF housing had copious amounts on oil in them. After a thorough cleaning, I am happy to report that the car runs better then ever.

I had the car throw a couple of codes the other day including PDK errors, low voltage and temperature sensor errors. fingers crossed, thankfully the stars were aligned (and the mechanics knew their stuff) and all is back to normal now - all linked to a dirty MAF sensor.

I've been through the whole MAF saga with an Audi in the past. It was judged that cleaning them with the MAF spray didn't fully fix it and cleaning it as a matter of maintenance wasn't a good idea because a thin film of the cleaning solution could even ruin the sensor. That thin wire is super sensitive... not sure if the condition of the MAF is more critical in a turbo engine?