Safety Interlock - Low Oil Pressure

[Mike_Windsor]

I was just wondering how difficult it might be to rig up a small electronic interlock to safeguard against catastrophically low oil pressure in the engine.


I was thinking that it would operate like so: Upon ignition, there would be a 5 second delay. Once the delay hit 0, it would begin continuously monitoring oil pressure in the engine just like a regular oil gauge does. If at any point the oil pressure drops below, say, 18psi the interlock shuts the engine off.

Thoughts?

[sly]

easy... delay timer hooked to a normally closed relay in series with a line to an oil pressure switch. The timer holds the relay open while the pressure builds (5 seconds). Timer is triggered by run circuit. oil pressure switch closes on low oil pressure (completing the circuit). Have this tied to another relay that is connected to the run power wire in NC fashion with the coil side to 12V and to the series from the oil switch. I'll draw up a schematic.

[Brown_Muscle]

I think it would be better to simply hook it up to an alarm or light, if the engine shuts off at an inconvenient time in which you need to speed up and can't...it could mean life or death.

[85crownHPP]

Set at 18psi, a few, if not many of our cars would shut off at every stop... but it's a good idea. Even triggered by the dummy light, it would still shut down when it didn't absolutely have to.
Maybe set it at 2psi somehow with a logic circuit... lol

[Mike_Windsor]

Well the existing oil sender is programmed to light up the light at 6psi, which is apparently too low to prevent damage.

2 years ago my car's engine was producing 50psi at idle...

18 is normal for some vehicles??

[Mike_Windsor]

... if the engine shuts off at an inconvenient time in which you need to speed up and can't...it could mean life or death.

If your oil pressure is dangerously low and you rev the engine, you're gonna kill it in matter of seconds in which case you'll be in a "life or death" situation anyways... unless you happen to be in the habit of stalling on train tracks or something...

[sly]

I'd try to find a very low pressure switch (like 2-5psi) to use on a T setup off the current pressure sensor.

[sly]

use something like this: http://www.goodswish.com/mx001/-p-1035.html

for the delay timer. Power triggers it... so have run provide power to it and the output being the Normally Open - CK - port. Common - COM - should be connected to Run source as well.

[Mike_Windsor]

You're so smart.

[85crownHPP]

Oil pressure that low isn't normal, but plenty of worn out 5.0's light up the light at idle but keep on truckin'...! And would probably still run until that last psi goes away.

But you're right, if it's making good oil pressure to start, I'd set a warning system up for a higher pressure than where the stock sender triggers. 10psi or less would definitely be too late if it were to spring a significant oil leak.

[sly]

You're so smart.

electronics engineer I am.

[Mike_Windsor]

Something I wanted to go to school for.

[tjc78]

My 79 Continental had the replace engine light on at idle for 30k miles. Couldn't kill that thing.

[79lincolnlover]

My 79 Continental had the replace engine light on at idle for 30k miles. Couldn't kill that thing.

Engine light is always on in my '79.

[Mike_Windsor]

My engine light came on once when the thermostat failed. My engine was a bit hotter than it was supposed to be.

But then again, some dipshit "mechanic" lit the goddamn thing on fire one day.

Anyways.