Low oil pressure shut-off, how SHOULD it work?

[Jan-78FJ40]

I was playing with the low oil pressure shut off on my 2H engine yesterday, and realized I don't understand it.
There are 2 wires coming from the switch. I can disconnect either one of them, or both, from the running engine, and the engine will not stop.
However, after an oil change, the engine will stop after a few seconds when the oil presure is not up yet, and will take another cranking over and starting to keep running.
Is my shut-off bad, or do I simply not understand it?
thank you,
Jan

[David*BJ70]

I think you have to ground it to stop the engine.... I think. That why we need a 3 ways switch for a kill switch...

[Eric Winkworth]

I dunno how the factory one works, but I was browsing around the Racor site and found an interesting system they have that I think would work good.

http://www.maesco.com/products/racor/r_eps/r_eps.html

They factory one, must restrict fuel somehow, I don't get it. How could it be a ground out, isn't it all mechnical?

[Jan-78FJ40]

Originally Posted by David*BJ70

I think you have to ground it to stop the engine.... I think. That why we need a 3 ways switch for a kill switch...

Yes, that makes sense. The manual says there should not be continuity between the wires if the engine is running. So low oil pressure allows for continuity, stalling the engine.
How would you wire the 3 way switch?
thank you,
Jan

[Tapage]

what is the low press min level to stall the engine . ? 5PSi or less ..

[Jan-78FJ40]

Originally Posted by Tapage

what is the low press min level to stall the engine . ? 5PSi or less ..

Oil pressure at idle should be 4.3 psi or more, and between 36 and 85 psi at 3000rpm, according to the FSM. I could not find what oil pressure triggers the switch...
jan

[Jan-78FJ40]

Originally Posted by David*BJ70

I think you have to ground it to stop the engine.... I think. That why we need a 3 ways switch for a kill switch...

if it shuts off when hot, why not wire in a switch between the 2 wires that shorts them unless pressed/interrupted?
what am I missing here?
thjanks
j

[David*BJ70]

Originally Posted by Jan-78FJ40

How would you wire the 3 way switch?

....this is what I WILL try... but I don't know if that will work...

So the 3 way switch will work like that :

One wire to the sender.
One wire to the ground.
One wire to the original wire.

So at position 1 : contact with the sender (not shut off)
and at position 2 : contact to the ground (engine shut off)

... all that figuring the third "switch" is in constant conection the the original wire to the EDIC.

Hard to write because it's french in my head... but I do my best to make it clear to you

[Jan-78FJ40]

Originally Posted by David*BJ70

....this is what I WILL try... but I don't know if that will work...

So the 3 way switch will work like that :

One wire to the sender.
One wire to the ground.
One wire to the original wire.

So at position 1 : contact with the sender (not shut off)
and at position 2 : contact to the ground (engine shut off)

... all that figuring the third "switch" is in constant conection the the original wire to the EDIC.

Hard to write because it's french in my head... but I do my best to make it clear to you

Merci, makes sense!
Jan

[Tapage]

Originally Posted by Jan-78FJ40

Oil pressure at idle should be 4.3 psi or more, and between 36 and 85 psi at 3000rpm, according to the FSM. I could not find what oil pressure triggers the switch...
jan

4.3 PSI .. ! woou .. to low .. and long range.

[89GASHOG]

FWIW, my 3B has never shut off immediately after an oil change. The one time it did shut off, it saved my butt though. A few minutes after an oil change, I was cruising down the road and the engine cut out. I started it up and drove off to a side road, where it died again. I got out, popped the hood and noticed that oil was leaking from the bottom of the oil filter. Turned out I'd not removed the old filter gasket so the filter wasn't sealing. I'd left an oil slick in my wake for a couple of miles. Fortunately, I was in walking distance of an auto parts store to pick up some more oil. A nice feature that prevented a dummy from frying his engine! Engine still runs as great as ever, with no smoking. It may have been a good thing, actually, because it really purged the old, black oil.