oil level sensor what does it do? & fuel pressure gauge question
 

My oil level sensor is not hooked up, im really not sure how long it's been like that. My question is what does it do? Despite the obvious? Does it illuminate any lights? Does it tell the ecu to dump more fuel? does it put it in limp mode. Does it even do anything?

Also i thought i would ask where do most guys put there fuel pressure gauges in? After the regulator? On one of the rails? Can you put a pressure gauge on the stock rails? I'll search too but i thought if someone could give me an answer about that while i ask my other question it might be quicker.

It just lights up in the oil pressure gauge a small light (similar to the coolant temp with the low coolant warning light). The ECU doesn't adjust for it.

I dont think my light comes on. Oh well, doesnt really matter, if i have no oil i will have no oil pressure.

I'm guessing it will only come on if its hooked up?