Imobilyser

Yvan · Post by **Yvan** » Thu Mar 27, 2008 8:10 pm

Just a thought... Cold MJLJ be programed to cut ignition intermittently, to simulate broken engine. So that it can be used for car theft prevention.

Post by **brentp** » Thu Mar 27, 2008 11:57 pm

Off the top of my head, you could enable a very low rev limit which would effectively make the vehicle un-drivable- especially if a hard rev limiter was part of the system.

Yvan · Post by **Yvan** » Fri Mar 28, 2008 11:44 am

How about a map filled with zeros and a hidden switch?

What happens if you set advance to 0? Will the engine run? I have quite high advance (compared to what I saw at ignition map library here), it goes from 18@1000 rpm up to 42@5500 rpm (that's @ 100 kPa MAP).

Or an configurable option to toggle rev limit value with an external switch?

MartinM · Post by **MartinM** » Fri Mar 28, 2008 12:23 pm

Will it run at 0BTDC - don't know. Why don't you try it?

If you do something clever with the map or rev limit, then the simple way to defeat it is to just disconnect the MJLJ (although that might not be a particularly obvious thing to do I admit!)

Seems all a bit complicated - if you're going to have a hidden switch then you might as well make it:
- control the EDIS power supply
- interrupt the VR sensor signal
- or something similar that stops the engine starting completely, rather than jumping through hoops to make the MJLJ do something

My $0.02....

Yvan · Post by **Yvan** » Fri Mar 28, 2008 3:30 pm

I know that I can do that. But I wanted something that would simulate bad running, cutting, stalling. I could use reed switch, and just use small magnet on a keychain to activate/deactivate this feature.

And I already do have hidden switch that prevents engine running (I had cut power to some relay, I do not remember which, I did that more than 15 years ago).

Post by **brentp** » Fri Mar 28, 2008 3:31 pm

I agree with Martin. A hidden fuel pump switch, for example, is an effective immobilizer. If the engine is fuel injected, it just won't start- otherwise the carb'd engines will run until the fuel is depleted from the bowl. Simple and effective.

Others have talked about a 'valet mode' where the rev limit is enabled at low RPMs. this could give the effect of a bad running engine..

... Or, I could just give you an old, buggy firmware build.

Dimbit · Post by **Dimbit** » Sat Mar 29, 2008 12:19 am

I know a lot of people here in the UK have an MOT map with a 1500rpm limit, so they can't go having any fun with your car while you're not looking. That's very effective. Alternatively cutting power to the coil works well because it'll still crank but not fire, so any would be thief would think it's just too cold or unreliable.