Okay, let me start off by saying I searched, and also that I feel like a jackass posting a thread when I think I have it narrowed down. With that being said, here's my issue;
Okay, drove my car into the shop due to a dead injector/timing chain replacement needed. We replaced the following, the 4 guides, 2 chains, 2 tensioners, rear main seal, coolant, oil (castrol 5/40 full syn), purolator filter, melling oil pump, oil pan seal, valve cover gasket, plugs, #1 injector, #2 and 3 injector orings.
We got it all back together, after cleaning all the guide material out of the original oil pump/pickup/tube with brake clean, the car sounds good, and throws no cel, nothing on vag com etc at idle, its great, if we free rev it to 5k still nothing sounds great no lights. Now if we hold it at between 1700-2k, it will throw the "low pressure" light with the oil can. Shut the motor off, hoping it wasn't starved. So I bought the melling oil pump, and fresh oil/filter. Pulled it apart, oil had completely circulated through the motor, filter, etc. Knocked some more guide material free from somewhere, laying in the bottom of the oil pan. Put it all back together, noticed a missing oring in the pickup tube, opposite from where it connects to the pump (there's supposed to be an oring there right???) And it does the same exact thing. Might I add that the motor has not yet made any noises or symptoms of any kind of oil starvation, no knocks/ticks/slapping/etc, quiet and smooth sounding, even when the oil light is present.
Idle...fine, no oil light.
Quick rev to 5k...fine, no oil light.
Hold the rpms 1700 to 2k, not fine, oil light on "low pressure".
So we unplugged the sending unit plug on top of the filter housing, started the car, results are the exact same. Now I just want some reassurance, I'm assuming the sending unit is bad, what do you guys think?
Thanks in advance.
One way to know is to install a press gauge and check the actual oil press and then to replace the switch. Or if you are confident about the press, replace the switch.