Substituted sender from my other RX7. No joy. Still doesn't work. This sender works on the other car so not the sender. Put another inst cluster in and it doesn't work either! At wit's end. Is there something else between sender and gauge?

 

question,
Is the engine making any oil pressure? have you checked with a manual gauge?
BTW more info would be helpful, year, engine and any mods done. also look into the fsm for wiring diagrams

 

85 GSL-SE w 13B no mods - has good pressure by manual dial gage. I have a factory shop manual I see nothing that makes sense unless something on the inst cluster backside. I may just need to go thru my experiments again.