Sensor question, 01M. G38, G68 Variable reluctance?

[a3clusters]

Are the sensors on the 01M tranny (G38, G68) known as "Variable Reluctance"?
They only have 2 pins. So they can't be Hall effect..... right?

[Charlie_M]

Are the sensors on the 01M tranny (G38, G68) known as "Variable Reluctance"?
They only have 2 pins. So they can't be Hall effect..... right?

Yes. I know the two-wire sensors in the 09A are VR (G182, G68 and G265), and are all identical. Are you trying to pick off a signal?

[pedantic] Atcually the VW SSP for the 09A is wrong, I think, calling these three sensors 'inductive' rather than variable reluctance. Inductive sensors usually carry just the coil and sense a magnet going around, while VR sensors carry both a magnet and a coil and sense any changing ferrous target.
[/pedantic]

[a3clusters]

Working on an old porsche that uses a VR type sensor on the flywheel for timing. The porsche sensor is discontinued. I've searched Hi/low.... only to find other people needing this part as well.
I'm looking for a cross.

Willing to try and see if these sensors work.
I don't have a working porsche sensor, so I'm not exactly sure what the signal looks like. I can only guess from standard VR signals.

[Charlie_M]

Working on an old porsche that uses a VR type sensor on the flywheel for timing. The porsche sensor is discontinued. I've searched Hi/low.... only to find other people needing this part as well.
I'm looking for a cross.

Willing to try and see if these sensors work.
I don't have a working porsche sensor, so I'm not exactly sure what the signal looks like. I can only guess from standard VR signals.

Ouch. If you have a non-working Porsche sensor, you can still tell a lot, especially if you are willing to dissect it. Heck, you may even be able to repair it; they are basically just a magnet, a pole and a coil of wire wrapped around the pole. I think the only things that fail are an open circuit, or wire insulation break-down causing coil properties to change (decreased signal and decreased coil resistance).

What does the flywheel target look like?

Pay attention to the gap: it's usually extremely small and extremely sensitive. These tranny sensors, and also the VW VR crank position sensors (ie, 1.8T) are all set to working gaps just by bolting them down, so you pretty much are stuck with what you get. You may want to look here: http://www.spectecsensors.com/magneticSensors.html for threaded body sensors that are easier to set gaps.

VR sensors are also very sensitive to EMI; VW has had a few TSBs regarding this where they go in and add extra shielding to fix an EMI problem.