Oil pressure switch

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I need both open and closed style oil pressure switches but can't figure out which performs what.

I need a switch for low/no oil pressure light.

I need a switch to power a fuel pump when engine is running. When no oil pressure is present, like engine off with key on, need the pump to turn off.

What style switch goes where?

 

[rivermobster]

I have that exact switch on order, but haven't received it! Lol

I wasn't going to use a light though? Just a gauge (from a different sender).

My plan was to have it (the switch) close the normally open circuit...

To complete the power circuit to the distributor...

Once the switch sees pressure?

But now you have me thinking I should wire it like you're talking. To cut power to the fuel pump rather than the ignition if we loose oil pressure?

The problem with that is, running carbs, it would take awhile for the carbs to go dry, if the oil pressure Does go away?

I suppose I should start drawing it all out on paper.

This is what I have done so far...

 

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I have that exact switch on order, but haven't received it! Lol

I wasn't going to use a light though? Just a gauge (from a different sender).

My plan was to have it (the switch) close the normally open circuit...

To complete the power circuit to the distributor...

Once the switch sees pressure?

But now you have me thinking I should wire it like you're talking. To cut power to the fuel pump rather than the ignition if we loose oil pressure?

The problem with that is, running carbs, it would take awhile for the carbs to go dry, if the oil pressure Does go away?

I suppose I should start drawing it all out on paper.

This is what I have done so far...

View attachment 1191119 View attachment 1191120

Fuel pump shut off is in case of an accident were engine shuts off it will shut the fuel pump off even with the ignition on, so the fuel pump won't pump fuel into a fire, if there is a fire.
Stick to your ignition kill.

 

[rivermobster]

Fuel pump shut off is in case of an accident were engine shuts off it will shut the fuel pump off even with the ignition on, so the fuel pump won't pump fuel into a fire, if there is a fire.
Stick to your ignition kill.

You running EFI or carb?

 

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You running EFI or carb?

Fuel injection. 3 cylinder Kubota turbo diesel.

 

[rivermobster]

Fuel injection. 3 cylinder Kubota turbo diesel.

I think this might be what you need for the light?

Have the light hot with the key on, and then have it ground through the normally closed side of the switch.

Then you could use the other side of the switch to close (complete the circuit) to the fuel pump relay, once the oil pressure comes up.

The only problem I see is...

Not having the 3 second prime that a computer normally provides, when you first turn the key on? You Could use a push button to provide the prime manually.

Does this make sense? Want me to draw it on paper for you?

ACDelco 88924472 ACDelco Oil Pressure Safety Switches | Summit Racing

Free Shipping - ACDelco Oil Pressure Safety Switches with qualifying orders of $109. Shop Oil Pressure Safety Switches at Summit Racing.

www.summitracing.com

 

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I think this might be what you need for the light?

Have the light hot with the key on, and then have it ground through the normally closed side of the switch.

Then you could use the other side of the switch to close (complete the circuit) to the fuel pump relay, once the oil pressure comes up.

The only problem I see is...

Not having the 3 second prime that a computer normally provides, when you first turn the key on? You Could use a push button to provide the prime manually.

Does this make sense? Want me to draw it on paper for you?

ACDelco 88924472 ACDelco Oil Pressure Safety Switches | Summit Racing

Free Shipping - ACDelco Oil Pressure Safety Switches with qualifying orders of $109. Shop Oil Pressure Safety Switches at Summit Racing.

www.summitracing.com

That switch has 3 blades. Its both an open and closed type switch? There is no computer on this engine. I can wire the fuel pump into the glow plug switch using a relay to use as a "prime".

 

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I think I figured it out.

I'll need a Normally Closed switch for the low/no pressure oil light, while the engine is running.

I'll need a Normally Open switch to have the fuel pump run, while the engine is running.

 

[rivermobster]

That switch has 3 blades. Its both an open and closed type switch? There is no computer on this engine. I can wire the fuel pump into the glow plug switch using a relay to use as a "prime".

According to @Shlbyntro , that's exactly how it works. The one I ordered just shipped today.

 

[rivermobster]

I think I figured it out.

I'll need a Normally Closed switch for the low/no pressure oil light, while the engine is NOT running.

I'll need a Normally Open switch to have the fuel pump run, while the engine is running.

I changed your description a bit.

 

[gottaminute?]

According to @Shlbyntro , that's exactly how it works. The one I ordered just shipped today.

l know there are adjustable(psi) versions out there but if you are ok at 5-7 psi three bladed com/no/nc switch, look at chevy vegas from mid 70s. that is exactly how they are used. "IF" my memory is correct, the start wire was tied to the fuel relay to pump while cranking.

 

[rivermobster]

l know there are adjustable(psi) versions out there but if you are ok at 5-7 psi three bladed com/no/nc switch, look at chevy vegas from mid 70s. that is exactly how they are used. "IF" my memory is correct, the start wire was tied to the fuel relay to pump while cranking.

 

[gottaminute?]

Electric Fuel Pump Wiring Diagram | GTSparkplugs

Simple and Safe electric fuel pump wiring diagrams

www.gtsparkplugs.com

this page shows diagram as well as info on switches(p/n s) .

and the little 3/4 round LED trailer side lights work great for oil pressure, alternator or temperature warning lights. especially on machines that vibrate. no filaments to break.

 

[rivermobster]

Electric Fuel Pump Wiring Diagram | GTSparkplugs

Simple and Safe electric fuel pump wiring diagrams

www.gtsparkplugs.com

this page shows diagram as well as info on switches(p/n s) .

and the little 3/4 round LED trailer side lights work great for oil pressure, alternator or temperature warning lights. especially on machines that vibrate. no filaments to break.

Handy! That's everything the OP needs.

 

[wzuber]

I use this kit on my circle boat. Adjustable psi, worx well so far. The led trailer light is great, bright. I think I have to buy another sender since I dunked it at the last race. Thx for the reminder...haha

 

[TimeBandit]

The Chevrolet Vega had a oil pressure switch that would kill the fuel pump when there was no oil pressure.

Why I remember a diag I did 42 years ago and not anybody's name is the bigger question.

 

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I ordered a 3 blade switch and have already installed it for my application. I'm using a red light/buzzer combo unit from Cole Hersee, if that's how you spell it. That's for the low oil pressure alert. I lied about the fuel pump, I'm using that blade to activate an electric fan to come on only when engine is running. I don't want the fan to run KOEO. Only run when KOER.

 

[v6toy4x]

You want a couple hobbs switches, they come psi adjustable or preset NO and NC

NO-normally opens is open when at rest so this would be for your fuel pump to shut off when there is low or no pressure on the switch

NC-normally closed is just the opposite so it would work for turning a light on

Here is a couple catalog pages

https://docs.rs-online.com/02c1/0900766b813e74cc.pdf

https://www.texasindustrialelectric.com/honeywell_pressure_switches.asp

 

[v6toy4x]

If thats not enough here is the "HOBS SWITCH RABBIT HOLE"

https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/switches/pressure-switches/standard-pressure-switches/common/documents/sps-siot-hp-he-mh-me-lp-le-pressure-switches-product-sheet-50094081-5-en-ciid-148581.pdf

 

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You want a couple hobbs switches, they come psi adjustable or preset NO and NC

NO-normally opens is open when at rest so this would be for your fuel pump to shut off when there is low or no pressure on the switch

NC-normally closed is just the opposite so it would work for turning a light on

Here is a couple catalog pages

https://docs.rs-online.com/02c1/0900766b813e74cc.pdf

https://www.texasindustrialelectric.com/honeywell_pressure_switches.asp

So I really just needed a switch to activate an electric fan when the engine is running and a switch to activate a buzzer when key on engine off so the battery doesn't drain which is easy to happen on this piece of equipment. Later on I'll get fancy and install some Murphy gauges for the safety factor.