MAF swap complete,
05-21-2002, 04:11 PM
#12
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The 2.0 MAF has an integral IAT sensor, which is not...
used on turbocharged vehicles, which have a separate IAT (intake air temp) sensor post-intercooler. Knowing the air mass (MAF) and post-IC pressure (MAP) and temperature (IAT), the ECU can compute the density of the air flowing into the engine. There's probably an atmospheric pressure sensor somewhere, too, which in combination with the others can be used to determine quite closely the speed the turbo is spinning.
BTW, I believe the Bosch part number is actually heat stamped into the other side of the sensor. The raised numbers shown in the pictures are more likely a number for the molded housing.
BTW, I believe the Bosch part number is actually heat stamped into the other side of the sensor. The raised numbers shown in the pictures are more likely a number for the molded housing.
05-21-2002, 04:20 PM
#16
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Don't forget ..
the tamper proof torque screws can be a real b*tch to remove. My reco is to get the TR20 head, and if it does not work on your stock, like mine, you will need to grip the screws (very small edge with something to get a good grip w/with a vice grip or needle nose (worked for me).
05-21-2002, 04:22 PM
#17
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Yes...
thte missing component on the top side of the MAF is a thermistor, used for measuring air temperature. You can see an outline molded into the plastic MAF housing showing where it goes. I'm assuming that's what you're referring to as the "missing wire."
It connects to a pin on the connector which goes nowhere on a turbo engine. The VW 2.0 engine uses the IAT sensor, and has 5 wires connecting to the MAF unit, turbo engines have 4 wires (but both connectors have 5 positions, obviously.)
It connects to a pin on the connector which goes nowhere on a turbo engine. The VW 2.0 engine uses the IAT sensor, and has 5 wires connecting to the MAF unit, turbo engines have 4 wires (but both connectors have 5 positions, obviously.)
05-21-2002, 04:29 PM
#18
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A warning...
based upon experiences VW TDI owners have had with the 2.0 MAF (the cheap one).
Like the TT engines, the TDI MAF is still priced at hundreds of dollars, and they fail on a regular basis. The failure is due to poor contacts causing excessive current draw and bad power to the MAF. VW has a "fix-it" kit with new contacts.
Anyway, the cheap MAF seems to work OK in TDIs, too, but it now appears that it is calibrated differently than the correct MAF. Just like what you've found, the sensor itself is physically interchangable.
It might be a good idea to collect VAG-Com readings from a number of different vehicles for comparison. (even better, the same vehicle with old, new "correct", and new "cheap" MAFs). Looking at idle at the measuring blocks dealing with MAF readings would be a minimum, but partial and full throttle readings would be best. VAG-Com has a capture mode which would be useful for the.
On the TDI, the cheap MAF seems to work fine for some, and throw a CEL for others. As I said, it appears to be calibrated differently, although that wasn't thought to be the case at first.
Like the TT engines, the TDI MAF is still priced at hundreds of dollars, and they fail on a regular basis. The failure is due to poor contacts causing excessive current draw and bad power to the MAF. VW has a "fix-it" kit with new contacts.
Anyway, the cheap MAF seems to work OK in TDIs, too, but it now appears that it is calibrated differently than the correct MAF. Just like what you've found, the sensor itself is physically interchangable.
It might be a good idea to collect VAG-Com readings from a number of different vehicles for comparison. (even better, the same vehicle with old, new "correct", and new "cheap" MAFs). Looking at idle at the measuring blocks dealing with MAF readings would be a minimum, but partial and full throttle readings would be best. VAG-Com has a capture mode which would be useful for the.
On the TDI, the cheap MAF seems to work fine for some, and throw a CEL for others. As I said, it appears to be calibrated differently, although that wasn't thought to be the case at first.