MS3X Oil pressure Safety

[PUMPISH]

Hi I installed 0-5V / 0-10 bar oil pressure sensor and I am wondering how to cut ignition/fuel off like rev limiter o when the pressure is too low? Allready checked CEL but would like to just use rev limit.

Thanks!

[Reverant]

Not currently possible.

[dontz125]

If you want it to cut RIGHT NOW, have the Oil Pressure Warning Output drive an interposing NC relay / transistor that interrupts the signal to the FP relay. Assuming the coils and injectors are powered throught the FPR, as soon as the pressure hits the '!!' level, the engine is chopped hard.

This has been discussed a few times; if this is a street vehicle, an immediate hard stop could put you and those around you at great risk depending on the circumstances.

[shainiac]

I don’t understand why the “street vehicle” statement is valid. No one is supposed to be driving MS-powered vehicles on public roads. I know that’s not really the reality, but it is at the user’s discretion. There are plenty of people who are using Megasquirt on race-only cars with very expensive and sensitive engines that would benefit from this feature. For me personally, this feature would keep me from scrapping my $2500 turbo if I lost oil pressure suddenly. I’ve had it happen before on a cheaper turbo and it was ruined. A feature like this would have been perfect.

[dontz125]

No-one is supposed to be driving "pollution controlled vehicles" with MS controllers on public roads in the US or Canada. That still leaves a LOT of older cars, and most bikes, that are entirely legal to drive around with an MS box.

For your expensive race engine, the work-around I mentioned may very well have saved your previous turbo, and just might save your current one.

[jacky4566]

Do you have the oil pressure light hooked up?

If so you should notice it flicker around corners letting you know oil is getting low.

And if you are really paranoid buy an accusump.

[DLRacing]

Cutting power in a corner could easily put you into a wall on track, or worse yet, a telephone pole, tree, or bridge abutment on the street.
I'd rather have a bright oil pressure light to warn me, so I can control the shutdown without getting hurt or killed.
A $2,500 turbo is much cheaper than a hospital stay.

[radial]

I have been looking for the same feature.
Especially the possibility to have a log of what was going on when...say a 1000rpm revlimit kicked in.

I think the feature is possible for water temperature though.

[DaveEFI]

I don’t understand why the “street vehicle” statement is valid. No one is supposed to be driving MS-powered vehicles on public roads. I know that’s not really the reality, but it is at the user’s discretion. There are plenty of people who are using Megasquirt on race-only cars with very expensive and sensitive engines that would benefit from this feature. For me personally, this feature would keep me from scrapping my $2500 turbo if I lost oil pressure suddenly. I’ve had it happen before on a cheaper turbo and it was ruined. A feature like this would have been perfect.

Eh? I have an MS on one of my cars and it's fully road legal. Even reports better emissions at test than when it left the factory.

Modern stuff with state of the art injection probably wouldn't benefit from MS anyway.

[slow_hemi6]

Do you have the oil pressure light hooked up?

If so you should notice it flicker around corners letting you know oil is getting low.

And if you are really paranoid buy an accusump.

Best suggestion, accusump!

[dontz125]

Do you have the oil pressure light hooked up?

If so you should notice it flicker around corners letting you know oil is getting low.

And if you are really paranoid buy an accusump.

Best suggestion, accusump!

Is there an alarm system involved with the Accusump? If not, the problem will only be delayed until the accumulator has blown down and you are once more out of pressure.

[slow_hemi6]

Correct. Your low pressure cut would then only trip under a real fault. Accusump gets rid of the nuisance trip factor by doing what it does. Protecting engines.

[cj.surr]

A rev-limiter set at 4000 RPM or wherever is appropriate is not going to leave you stranded in front of a truck in an intersection. It's just going to slow you down when you're floored and let you know something's up before you destroy your hardware. It's about time this feature is implemented.

[PUMPISH]

I don’t understand why the “street vehicle” statement is valid. No one is supposed to be driving MS-powered vehicles on public roads. I know that’s not really the reality, but it is at the user’s discretion. There are plenty of people who are using Megasquirt on race-only cars with very expensive and sensitive engines that would benefit from this feature. For me personally, this feature would keep me from scrapping my $2500 turbo if I lost oil pressure suddenly. I’ve had it happen before on a cheaper turbo and it was ruined. A feature like this would have been perfect.

Are you serios?

I have been running MS on ALL my cars last 10 years now, both my race cars and winter daily drivers

[PUMPISH]

Do you have the oil pressure light hooked up?

If so you should notice it flicker around corners letting you know oil is getting low.

And if you are really paranoid buy an accusump.

I want to use all function I can so I dont need to look at the gauges, its pretty safe for a 1000hp daily driver

[PeteJ]

Or just use one of these...https://www.holley.com/products/fuel_sy ... rts/12-810

[Raymond_B]

Or just use one of these...https://www.holley.com/products/fuel_sy ... rts/12-810

I would be worried about shutting the fuel pump down and the Megasquirt not "knowing" about it. Seems bad to me. I would want all the logic in the engine control computer.

[jsmcortina]

Oil pressure can trip a Limp Mode.

James

[PeteJ]

I run a dry sump and my concern is a belt coming off or any other issue that would cause the pump to stop. An option I've been thinking of is have the oil pressure sensor trigger one of the outputs on a low pressure. Like shown here:

Oil Pressure Safety1.JPG

That can be used to enable one of the rpm limits (for example launch 3) say less than 500 rpm. like shown below


I would have to play with the pressure/rpm curve but this will allow the car to crank and start just fine and since my car will not idle at 500rpm (or whatever rpm I choose) it will effectively shut the engine down and protect itself. If you don't like the idea of killing the engine while driving set the rpm limit to something like 1000 rpm, this will allow the engine to keep running but will give you notice that something has gone seriously wrong.

Thoughts?

[briansexsmith]

I run a dry sump and my concern is a belt coming off or any other issue that would cause the pump to stop. An option I've been thinking of is have the oil pressure sensor trigger one of the outputs on a low pressure. Like shown here:

Oil Pressure Safety1.JPG

That can be used to enable one of the rpm limits (for example launch 3) say less than 500 rpm. like shown below


I would have to play with the pressure/rpm curve but this will allow the car to crank and start just fine and since my car will not idle at 500rpm (or whatever rpm I choose) it will effectively shut the engine down and protect itself. If you don't like the idea of killing the engine while driving set the rpm limit to something like 1000 rpm, this will allow the engine to keep running but will give you notice that something has gone seriously wrong.

Thoughts?

Peter, can you explain what you are doing with the launch control? Are you sending jumpering IAC2 into the launch in to get a hard limit of 3800 RPM? I see the transbrake output is also on IAC2 so I am not sure how you are making this all work.

Thanks
Brian