HI, I installed a Low pressure warning light into the oil blank plug hole on the back of my my cylinder head - its a 20psi switch that lights up below this pressure. I also have a oil pressure sender in the normal place on the block. During a moderate acceleration above 4000rpm the low oil pressure sensor light comes on from the head however the main block sensor shows oil pressure to be about 40psi. If i maintain the rpms the light stays on, if i let the rpms drop the oil light eventually goes out. Is there some sort of bypas or pressure relief system in the head ? (It's a VVT head on a TBD earlier block) The engine was recently rebuilt. I can't find much info on what should be happening to oil pressure in the head.....

Thanks in advance for your help and things to look for

 

https://www.miataturbo.net/diy-turbo...ey-plug-75112/

 

Look at the next to last post on that thread. i dont think the head recieves full pressure due to the block restrictor. You also have the VVT taking oil pressure away from the overall system. It seems to be more noticable on those with VVT head and Non-VVT oil pump.

 

Thanks, I think you are right. I also just moved the sensor to the oil pump and found it's doing the same thing as on the head, so I think I have a faulty sensor - so I'll be returning it....Next step will be to fit the new sensor and I'm now interested to see what is really going on at the head so ill borrow a pressure gauge and take some readings...Thanks for your posts