While my power steering pump was down (there's a story in that, later), I decided to change out my oil pressure sender. I replaced it with an FAE brand with part number 928-606-203-04, which should be the correct superseded part number. Now that it's in there, I'm not getting a reading on the gauge, although the warning light isn't on, either. I know there is pressure. When I disconnect the gauge wire from the sender and apply an 80 ohm resistor to ground, the gauge shows between 2 and 3 bar, as it should. I read the resistance off the gauge post, and I'm getting around 5k ohms (according to Clark's garage, 5 bar should be 184 Ohms). Why is my resistance so high? And wouldn't that peg the needle?

 

Aftermarket stuff is hit or miss. VDO units are in the 80-90 range.

 

Well, I know this isn't helpful for your current situation, but FWIW, I just put in an OEM Porsche sensor in my 944 and it seems to be working fine. Of course, it costs 3x the FAE brand version on PelicanParts, but sounds like it might have been worth it in this case from your experience.

 

Epilogue: Put the VDO sender back on and it works fine. So bad aftermarket sender it is. Thanks for the suggestions!