I'm thinking about installing a low oil pressure switch in a 1987 Toyota pickup. What wire would you recommend I splice into to shut the engine down when low oil pressure is sensed. My grandson doesn't seem to get the message about keeping check on the oil in the engine.
thanks

 

Well, there's quite a few different ways it could be done. But after some fairly long deliberation, I've decided which way I would do it. I would put such a switch between the EFI main relay and ground. One of the 4 terminals/pins on the EFI main relay connects to ground(body/engine). That's the circuit I would use. Don't ask me why...

Anyhow, whichever way, you want to cut power to the +B and +B1 terminals/pins on the ECU, or power from E1 to ground(engine/body). That will kill the engine.

See this page from the FSM showing the ECU power supply circuits.
http://personal.utulsa.edu/~nathan-b...37efimainr.pdf