MAF cleaning... Easiest project yet and a must. - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Mass Air Flow Cleaning: Cost Under $20, $7 if you have the tool. My 2001 "s" 67k mile was starting real ruff and had thrown a couple codes. White smoke was also evident when first starting. This simple 10 minute job fixed all of the the above problems. Codes: 1.)p1133= oxygen sensor, adaptation, lower load bank two above limit. 2.)p1126=o2 sensng range 1 cyl 4-6 Difficulty: 1.5 out of 10 (pretty basic) I followed the directions below but found a few shortcuts. http://sites.google.com/site/mikefocke2/checkenginelightcausedbymassairflowsensor Tools: 1.) t-20 tamper proof torx bit. (I used a bit that fit in my screwdriver rachet thingy) tamperproof= a frickin hole in the bottom of the bit. 2.) Can of MAF sensor cleaner(autozone $7.00) Procedure: 1.) disconnect batter 2.) open engine compartment 3.) next to your air filter you will see the Maf, unscrew the two screws(t-20 TP) 4.) REmove the MAF sensor( I didn't unhook any wires) 5.) Place a couple paper towels on you engine and spray off the sensor, make sure to squirt it up in the hooked end and the paperclip looking thing at the top. 6.) let dry (5 minutes) 7.) put back together and connect your battery. Thats it. Simple 5 to 10 minute job and hardly any mess. If you see oil or sludge on your sensor you probably have another problem up stream. Mine looked clean but after cleaning it, all my gremlins went away. Projects completed: 1.) Serpentine belt...........$25 Gatorback w/ac 2.) Sparkplugs..................$42 Ngk-Ix-Iridium 3.) Radio replaced............$225 JVC HD50 (BB install) 4.) Tires............................$700 Sumitomo III Local shop 5.) Oil Change/air filter.....$94 catro syntec 10W40,napa gold,K&N air 6.) Speakers....................$143 Infinity Kappa F=4", R=6x4 plate 7.) Throttle body clean.....$5 Throttle body cleaner 8.) De-snorkel..................$.10 A few paper towels 9.) Alternator...................$221 Various Sockets 10.)Fuel filter...................$30 10mm socket and flat head screwdriver 11.) MAF sensor clean.....$20 t-20 tamp proof and cleaner

Maybe disconnecting the battery solved your codes/problems. This resets the ECU / codes... Mark.

The MAF isn't likely to be the source of smoke at startup.

Is disconnecting your battery necessary for the MAF cleaning? I have not done this but wanted to know. I will be getting into my engine bay this week to have a "look see". Thanks in advance.

The battery only temporarily takes care of the codes. They would come back on after about 40 to 60 miles. I am over 150 miles and car is back to normal. Apparently the cleaning did take care of the white smoke on start up. Smoke before, no smoke after You will want to disconnect your battery after the job is done anyways to reset the cpu, so you might as well do it before to prevent any possibilities of shorting something.

It's been noted on this board, and I've personally observed as well, that the car will smoke at startup if it wasn't warmed up on the previous run before being shut off. On my car, it hasn't smoked if the car was warmed up when I shut it off previously. The MAF can't have anything to do with smoke at startup. The MAF is technically known as a hot-wire anemometer. It functions by monitoring the current through a wire at a known temperature and calculates an airflow based on a convection coefficient correlation. It requires that the anemometer is up to operating temperature, which it is not when you first crank the engine.

I don't know why you are arguing with me. Before the Mass airflow my care would startup, spit and sputter for a couple of minutes and it would turn my garage into a white fog zone. After the air flow clean, it starts fine, idles fine, no codes and no smoke. I don't know what to tell you. I am just making an observations. Haven't had smoke in 300miles since. Maybe it was something else that mysteriously fixed itself. I really don't know. I have had the cloud of smoke in the past on start up when I hadn't driven it for awhile, but this was much more profound and in greater volumes.

I guess I misunderstood. The smoke came after it was running then, not from starting? That makes sense.

How long was the battery disconnected during the MAF cleaning? What about reprogramming the radio?

Blue2000S, IMO, you're correct... I've also noted that if I pull the car out of the garage, wash it, put it back in the garage then take it out 2 days later it blows blue smoke - everytime. If I drive it put it away and take it out the next day for another drive it doesn't blow smoke. I have a theory that it has to do with the pressure in the engine when you start it but don't let it warm up it has higher pressure so the oil seeps through and when it's warm the engine doesn't have as much air pressure in it... This is just a theory, I'm not a mechanic. -Steve

Yep we probably were talking about two different, but similiar things As for the radio codes: I swapped out the hunk of junk last year(best thing I have done to date). You will need your code. It only takes about 10 or 15 minutes, but I always let it off for an hour or even overnight. Let me reiterate this. This operation is almost free and almost foolproof. As long as you don't short out the sensor when you take it out, no harm can come from this and it really needs to be done from time to time, Heck I would do it Yearly or Bi-yearly.

I totally agree! This was a simple project I would not have thought about had it not been for my check engine light coming on. After taking it to Auto zone for testing, they could not find the fault code. On a whim I decided to try this. It worked! Light went out. Car definitely runs just a hair faster. Cost is minimal, (especially compared to taking it into the dealership for diagnosis), time investment is minimal. Just do it. Your car will thank you.

I have had two occasions with the CEL light on my 2001. Both times I had a rough idle at start up and the car would sometimes blow smoke on the initial start. The first occasion also followed the installation of a K&N air filter. I didn't notice if I had run the car previously without a thorough warm up or not, as mentioned by another post. My mechanic claimed it was a faulty air oil separator and coincidentally the MAF sensor also needed replacement both times. He blamed it on infrequent driving and long intervals (5000k miles) between oil changes. $1250 for replacement of both, each time. Research indicates a faulty air oil separator can cause high manifold vacuum causing oil ingestion into the induction system, which could explain the smoke and contaminated MAF sensor. I am curious why the air oil separator would fail, how it fails, and why my mechanic would not clean my dirty MAF sensor instead of replacing it. (other than greed of course). Any expert knowledge on this problem? It sound common considering the number of posts.

And your car is more than a few years old and the plastic is exposed to repeated heat cycles. It generally fails by cracking in one of several places. The AOS tubing enters the airstream downstream of the MAF. The MAF is generally contaminated by a dirty air filter or over oiling of the K&N air filter...which isn't the best filter, incidentally, as it lets through more dirt. Normally, if an AOS failure contaminates something it is the O2 sensors in the exhaust system. And the throttle body.

Finally bought a can of air maf sensor cleaner and eagerly removed the maf to clean.... Unfortunately (or fortunately..._), my maf is absolutely clean, so clean that I didn't even bother to use the maf cleaner... This is a 2001 base box with 44k km... I guess the stock air filter works well ! I should be moving on to a pipercross or bmc filter soon, would be interesting to see if the maf get dirty then...