oil sending unit

[daveM]

'87 Chevy Pickup 4.3L TBI

So I hung a oil pressure gauge off the top of the motor (left of the distributor). Put a ‘T’ so the fuel switch still functions. Works fine.

Today on checking out one of many oil leaks I have, I notice there is also some sort of sending unit by the oil filter. Can’t seem to find any info on that sending unit. Might it just be for the idiot light and the one on top only for the fuel relay?

Dave

[piecesparts]

I believe we have discussed this before, this is the oil pressure /fuel cutoff switch on later vwehicles and on mid eighties years it ws tied to the intiation of the circuit for the choke on the motor. The oil pressure goes away, this will shut you down and hopefully save your motor, and for the choke, if the oil pressure dies not come up then the choke would not work.

[daveM]

Originally Posted by piecesparts

I believe we have discussed this before, this is the oil pressure /fuel cutoff switch The oil pressure goes away, this will shut you down and hopefully save your motor,

Actually the oil pressure switch is just a backup to run the fuel pump if the relay fails. It closes on 4 PSI. It will NEVER shut down the engine.

Well I guess it would if the relay was NOT working. You cranked the engine enough to get 4 PSI which would turn on the fuel pump and let you start. Then later while motoring down the freeway you lost oil pressure the pump would shut down. But that would only be if the relay was faulty and not working.

If the relay is working no oil pressure will open the switch but as the relay is working the pump stays on and the engine will destroy itself.