Oil Switch?

[COMMY VP 666]

hey

where is the oil switch for a 92 vp, and what does it do???

[jas98]

the oil switch (oil pressure sensor) is located where the oil filter is. it detects oil pressure and if to low will set the dash light off. Also if oil pressure is way to low (i.e no oil....car rollover etc) it will cut the fuel to the engine as the fuel pump is wired in with the oil pressure sensor. (this is my understanding)

[centy]

Also if oil pressure is way to low (i.e no oil....car rollover etc) it will cut the fuel to the engine as the fuel pump is wired in with the oil pressure sensor. (this is my understanding)

disregard this bit please it is incorrect.

[Pub247]

Yep vnv8driver started this bullshit and its spread like wildfire its the most misinformed thing about oil switches going around i wish every instance of this statement could be erased. ive run plenty of motors without an oil switch plugged in or even there using a pressure gauge instead

[immortality]

Yep vnv8driver started this bullshit and its spread like wildfire its the most misinformed thing about oil switches going around i wish every instance of this statement could be erased. ive run plenty of motors without an oil switch plugged in or even there using a pressure gauge instead

that is correct, on VN/VP the fuel pump has 2 supplies, one switched from the ecu through a relay and another through the oil pressure switch. for the VR and VS however they did alter the wiring a little. for the VR/VS the fuel pump is powered through the relay only. when the ecu switches the relay the fuel pump is powered from fuse No:23. if the ecu hasn't switched the fuel pump relay on then the fuel pump is powered through the efi relay and fuse No:10 through the oil preesure switch (when there is oil pressure). the fuel pump relay is wired NO (normally open, so requires a closed circuit) from the ecu. the oil pressure switch is wired to the NC (normally closed) side of the fuel pump relay.

check this link to see what i mean VR wiring diagram

however, the trick question is, does the ecu on the VR/VS maintian a complete circuit to power the fuel pump once the car is running or does it only "prime" the pump before starting the car? might have to check this out on the missus VS i think

edit, just been out and tried this on the missus VS, run engine and then removed plug from the oil pressure switch. engine kept running. so this means that the ecu keeps the relay closed and powers the fuel pump. so it is a complete myth about the oil pressure switch. i do however beleive that the "roll over/accident" protection by powering the fuel pump through the oil presure switch is what holden was intending to do, however they stuffed it up when they use the ecu to run the fuel pump relay when the engine is running, it should have been designed is such a way that the ecu only primes the fuel pump (when starting the car) and then the oil presure switch takes over once the engine is running. maybe they got it right in later model cars, for the VT the oil pressure switch is wired directly to the ecu so in theory it might work. anybody with access to a VT want to find out?

[Brin]

My VN (vr v6 engine) will not run with no oil pressure switch.....

It blew the fuel pump fuse every time you turned the key in the ignition. Put a VH switch in there temporarily and she ran perfectly again.

Does this disprove your theory..?

[jas98]

yeh i know about the so called "myth" but i remeber reading about it and also the guys at Holden told me about it a few years back....so sorry if i misinformed anyone. im only saying what i have been told buy a fair few people (not of whom was on or ever been on this site)

[immortality]

My VN (vr v6 engine) will not run with no oil pressure switch.....

It blew the fuel pump fuse every time you turned the key in the ignition. Put a VH switch in there temporarily and she ran perfectly again.

Does this disprove your theory..?

your case is slightly different, your's blew up (never seen that before) so it probably shorted out the contacts also blowing your fuses

[Brin]

I see I see, BUT - the switch i'm using at the moment - the VH one, if you unscrew that, the car wont start and it blows the fuel pump fuse.

Even without a switch, if you screw a bolt in there, it primes the pump. As long as it is secure and the engine senses oil pressure, it will start. I have tried this.

Come over my place and see for yourself lol.

[Brin]

I have the wiring diagrams from a manual (EFI Engine Management Vol 2 - handy book to those interested) that is photo copied in my room somewhere...

I'll find them tomo and try post em up - coz the wiring diagram clearly shows that the oil pressure switch is wired directly to the fuel pump fuse relay.

I'm not lying, I swear!!

[centy]

brin replace your relay and check the earths.

[immortality]

I have the wiring diagrams from a manual (EFI Engine Management Vol 2 - handy book to those interested) that is photo copied in my room somewhere...

I'll find them tomo and try post em up - coz the wiring diagram clearly shows that the oil pressure switch is wired directly to the fuel pump fuse relay.

I'm not lying, I swear!!

it is, VN/VP has 2 power sources for the fuel pump, through the oil pressure switch and from the relay switched by the ecu. both are fed from fuse 21. check wiring diagram HERE