One MAF gone after 5 days, second gone after 11 days! WTF?
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Quote:
Bingo.Originally Posted by Scottslaw
Exactly, my personal belief is that its not the oil that is the true culprit in many circumstances (although over-oiling can certainly cause problems). My personal theory is that its the non-laminar flow that results from a cone filter that causes problems with the MAF. It could also be a function of the proximity of this non-laminar (i.e., turbulent) flow to the maf sensor that results in some intake designs. The air coming off the cone filter is turbulent, causing issues. Having nice, orderly flow has to be important since the stock filter has a plastic grid in front of the sensor wires, that are (presumably) intended to straighten out the flow. .
A MAF works by ramping up the current to the sensor as the airflow increases... essentially it is trying to keep a thermocouple at the tip at a constant temperature as the airflow increases...the current needed to DO this is proportional to the airflow. (Classic hot wire anemometer)
At high flow rates, the circuit is running a significant amount of current- if you get buffeting, turbulent flow, weird things, you can get a 'null' at the sensor where airflow drops suddenly (but only at the sensor)...the sensor overheats immediately- POP. IMO, this is the classic V-Flow failure mode.
This is entirely different than the slow 'fouling' that oiled filters create. With this fouling, the maf can get ruined over time as the self cleaning cycle tends to allow an oxide layer to build up on the sensor. It always things there is more flow than there is, engine adds more fuel, but the LT ad ST fuel trims will correct this...as best they can. Ultimately you'll get a fuel trim error. (This latter mode seems to be less common in the TT and other FI cars.... common in NAs)
Agreed. I tried a dry filter, as well and it blew just as fast as the oiled one.
Using any silicone based spray lube/cleaner on a filter or near a running engines intake will damage the MAF, maybe the filter oil is not just an oil?, or is wet with oil, only spray on enough to get the dust to stick don't soak it. this is true of silicone spray on any modern MAF sensor. When you detail use a water based spray don't get crazy and never spray 100% heavy silicone in the engine compartment, especially if its, running, not sure about Walter detergent(WD40) have sprayed that and have never had a problem, still never while running, and when cleaning TB use spray intended for use with a MAF sensor .