4.3 , oil pressure sensor?

[Mikey N.C.]

Is it possible, that the oil pressure sensor for fuel pump , gets enough pressure to keep fuel pump running. But have solid alarm. Blue wire from sensor for gauge read 0 psi. I hooked a manual oil pressure gauge to sensor at back of block, behind intake and have o psi, but motor will keep running.
Are both of those oil galleys coming from rear main ?
Any advice. Or experience with this ?

 

[kghost]

The oil pressure SWITCH (cut off) which controls fuel pump power is at oil filter location on the 4.3 for NON EFI.

The SENDER typically at rear of Intake manifold is for displaying pressure on gauge.

Not 100% where the low oil pressure switch for Alarm switch is located. May be tee'd at oil filter location. I forget!

Three components for oil pressure are:

1. Sender- Output to gauge in OHMS
2. Oil pressure switch (Alarm) - Not sure what the oil pressure setting is to activate alarm but should be 5 psi or less?
3.Oil pressure switch - (Cut off for fuel pump) - On/Off Switch typically needs to see 5 psi or more to close to keep pump running



Blue wire that goes to Sender and the sender outputs in ohms to gauge

Tan with Blue wire goes to Oil pressure switch (Alarm) and there are also (water temp and low gear oil all tied into alarm circuit)

Purple and purple/yellow go to Oil pressure switch (Cut off for fuel pump)

 

[Dieter]

Is it possible, that the oil pressure sensor for fuel pump , gets enough pressure to keep fuel pump running. But have solid alarm. Blue wire from sensor for gauge read 0 psi. I hooked a manual oil pressure gauge to sensor at back of block, behind intake and have o psi, but motor will keep running.
Are both of those oil galleys coming from rear main ?
Any advice. Or experience with this ?

If you have measured zero oil pressure with a ,mechanical gauge while running you have an oil pressure issue and would think you have to either replace the pump or engine is worn. Either way pull it and drop the pan

 

[kghost]

If you have measured zero oil pressure with a ,UOTE]mechanical gauge while running you have an oil pressure issue and would think you have to either replace the pump or engine is worn. Either way pull it and drop the pan[/Q

He could also pull distributor and try to run oil pump with a drill and appropriate tool and see if the pump is working without engine running before pulling engine out of boat.

This may give a result of Bad oil pump or bad bearings/other internal issue.

 

[Dieter]

If you have measured zero oil pressure with a ,UOTE]mechanical gauge while running you have an oil pressure issue and would think you have to either replace the pump or engine is worn. Either way pull it and drop the pan[/Q

He could also pull distributor and try to run oil pump with a drill and appropriate tool and see if the pump is working without engine running before pulling engine out of boat.

This may give a result of Bad oil pump or bad bearings/other internal issue.

true , also could measure at port above oil filter and see if he gets anything different. Not sure if its possible but wondering if passage up to switch by distributor can get plugged due to sludge ? Thats the only way i could think that he could have zero psi oil pressure and not have an engine that is noisy as hell lifters and rod bearings clanking …