So I found a slightly used MAF housing and sensor on eBay last week. The housing was specific to a Passat, but what many don't know is the important sensor inside the housing is the same for many VW's including mine. VAG (Volkswagen Audi Group) dose not want you to know you can get the sensor for cheap on certain models and then just swap out the actual sensor for the VR6. I think I've seen dealer quotes for a new MAF (Mass Air Flow) for the VR6 in the range of $300+ vs $100 for other model cars.
Here is Passat MAF complete. $20 shipped vs a new at $300+
The MAF sensor is a sensitive electronic device that samples the air as it enters the throttle body. Based on the readings (ie, air temp, oxygen, humidity, etc) it sends a signal to the ECU to adjust the many aspects of the motor that effect performance and emissions. Over time, and especially with an aftermarket airbox/intake the sensor can get dirty/contaminated which effects mpg's and emission and if left dirty long enough can fail and cause a Check Engine Light (CEL).
Here is the sensor inside the housing from the back side:
I'm not getting a CEL, but my mpg's are not that great, IMO, and I don't really know the maintenance history of the car. This sensor (on every modern car) can and should be cleaned regularly. It's fairly easy.
What I did this past Monday, was swap out the current with the "new" one and give it a whirl. If I had MAF cleaner that day I would have cleaned the new one for giggles before I put it in, but I was curious with the swap procedure so just went for it. The item that came in the mail was very clean as if it were new...even had the plastic covers over each end of the cylinder MAF housing.
Here is my VR6 MAF housing and sensor connection:
To swap out, it's very easy, just unplug the connection socket by squeezing the tab on the side and use a flat head to gently pry underneath and it pops right off.
Now the sensor is connected to the housing by 2 tamper screws. The Passat had a 6 point tamper torx and mine had a 5 point tamper torx. The corner auto parts store had a set of 6 point tamper torx for the Passat sensor but nobody had one for mine. Therefore I just used a pair of pliers on the outer edge of the screw and with a little patience was able to remove the 2 screws. I figured I could swap the screws to make life easier down the road, but unfortunately they are a different thread coarse. I could take out my dremel and cut a slit in the screw top for a flat head...but not this day..I'll wait on that.
Once the screws where removed, it's as simple as inserting the new one, being VERY careful not to touch any of the "metal" parts. The direction of the sensor is important but you cant screw it up by the way it's designed....it can only line up in the correct direction.
Now since doing the swap on Monday, I have had no issues with the change over. I have also since bought a can of MAF cleaner. So last night I removed the "new" sensor and gave it a good liberal spray with the cleaning solution. Let it dry, installed it in the housing again, but didn't connect the socket until the next morning.
So far I have only been driving 15 highway miles (20 total) to work and then 15 hwy miles back. I have not seen a massive increase in MPG's but my ultimate test will be when I drive for 3 hours to Daytona this weekend for DubJam and WinterJam. I plan on putting the car in cruise at 3k RPM's (~70mph) and see what the average I can get. Right now I get about 21-22 mpg to and from work when I try REAL hard to keep the rpm's low.
If it dosent show a decent improvement, then I'm going to swap out the plugs (again no history), then all the coils and finally the O2 sensors.
Cheers.
