Kill switch how-to

[jtgh]

sorry , was pop off to store and in hurry.
any switch that can open will work for the thieft. sure SPST is minimal but not mandatory.
2 pole , 3 pole , single or double throw.
it's just a switch and the current is not an issues nor the voltage.
12v, zippo current.

we call this a Any in the junk box , switch.
toggle.
maybe you might us a key switch. who knows what suits your fancy.

cheers.

[Piwoslaw]

Originally Posted by jtgh

one newer cars the cam sensor is well on the end of the cam , where else.?
some have 3 wires other many .
3 wires, power , ground and output.
others have more outputs, (like I said, lots and lots of ignition designs)

POP QUIZ:
You have an average cam position sensor with 3 wires:
1. supply (+5V),
2. signal,
3. mass.
Which is the safest to disconnect to stop the engine?

Extra credit question: What happens when you ground the signal wire (short it with mass)?

[jtgh]

cut fuel can only be done , so many ways. (each car make can be diff. I can help)

kill the drummer boy (CMP) (with temp DTC 41/42)
kill spark directly to the Ign coil(s). ECU detects this and kills fuel in 1sec. or so.
killing CMP has the benefit if , allowing ECU to react fast, it must cut fuel.

CMP = CAS (cam angle sensor)

killing power to the ecu and worse everything, is not good to do , 100 times a trip.
not smart to torture any electronics, like that.

consider this, when you flip a switch , the rise time is almost instantaneous.
The Ecu was designed to allow that , action but not in to excess.

how ever one can design a so called soft power on circuit.
basically a RC circuit that gates on a Bmos driver. (similar to an injector driver)

there are lots ideas and ways of doing this.

The ecu does have lots of internal protection.
for things like the A/C clutch solenoid that products up to 400vdc back EMF spikes.
it is not weak, but torturing it needlessly is not wise , IMHO.

im a tech, im the guy that repairs the damage to the PCB's after the above.
worst is Lighting. (lots of stories)

cheers

[jtgh]

safest question.?

that is easy, cut the Signal. (and ignore the DTC, it should clear ,next power cycle.)

cutting power and ground is bad,

you do know? , that life testing of Assemblies under test
exploit 3 weakness (to simulate Time ,ie: life testing.)

1: power cycling..... hummmmm.
2: heat
3: clock rates. ( fast RPM in this case) high = get hotter and other things bad.

So cut the clock, the output other sensor is low current and it is harmless to
cut it , open and then back closed.
very harmless in fact.

on my car the Sensor driver is an open collector driver transistor
driving the ECU input transistor gate with a series resistor (protection) and
and pull up to 5vdc ECU internal supply.
opening this line is not harmful in an way. see links.

here is my spark page for sidekicks ( 89-98)
I am sure I have no spark

here is the guts of my CMP

http://kick-fix.com/IGN_timing/DIZ-CAS1W86.jpg


we can find these facts on your car too.

it is not hard.

cheers

[jtgh]

this is all HS, electronics 1a.
but here goes.
shorting any signal?

there are many kinds of drivers in electronics.
pass passive, or active. ( are the 2 families.)
and there are drivers that hare pull up passive (resistor) (my Dizzy CMP)
active pullup to 5v or 12v via a transistor.
and then there are totum pole drivers. active UP and Active down.
Digital logic uses this for max speed.
active pullups and pull downs are common.
some are current limited, by passive or active means.

there are 2 fail paths a short to 12v and a short to ground.

a short to ground, many totem pole driver will overheat and blow out.
for example shorting the output of driven injector line can in fact blow it out.

The CMP (cas) can be any TYPE , any at all, we are talking here of cars made from 90 to 2010. (mostly) and they vary all over the map.

many drivers are output short protected. you need to find out the circuit type.
but in this case we are opening it.

There is no need at all to allow the line to ground out.
use quality wire, and some split sheathing. This can be done easy.
the signal is slow and low tech, and can be a long wire.
i hope this answers and opens , interest in real electronics. cheers.

[Piwoslaw]

I found my engine's cam position sensor today. Three wires (+5V, signal, mass). When I unplug it, the engine doesn't start. But once the engine is on and I unplug it, then the engine doesn't stop.
What now?

[Nerys]

I am thinking maybe because your running a diesel? they are pretty much self sustaining once you get them going. I am not sure why yours would even have a cam sensor ?? no spark plugs to fire so no reason to know the location of the cam?? unless its for fuel injection or something? (I know very little about this just a guess)

[dcb]

my diesel injector pump has a solenoid on it to turn on the fuel, I was planning on interrupting that for a diesel kill switch.

[Nerys]

Interesting. How do you "restart" a diesel ie how long do you have to wait for the glows to rewarm?

[Piwoslaw]

A diesel is self-sustaining, but new commonrail turbodiesels are very dependent on sensors and what not to ideally time the injection. Cutting the cam sensor is what they told me when I asked at the Peugeot forum. I'm thinking (this is just guessing) that the cam sensor is needed when starting to know what position the pistons and vavles are, later it's just automatic. If the cam sensor dies during operation, then the calculator can use the crankshaft sensor's input. This afternoon I found what I think is the crankshaft sensor, but pulling it neither prevents the engine from starting, nor kills it if it's already working. I didn't try pulling both the crankshaft and the cam sensor at the same time, so I don't know if that would work.

Re fuel pump: I read somewhere in this forum that there is enough pressure in the fuel lines between the pump and injectors that the engine could go another 2 blocks before running out of fuel. Also, I'm not sure how the injector timing and combustion would be upset with lower pressure (more smog?). I know some have been lucky with killing the injectors, but that's not something I would try in my engine. I'd try if I were planning an engine swap in the near future.

Originally Posted by Nerys

Interesting. How do you "restart" a diesel ie how long do you have to wait for the glows to rewarm?

The glow plugs are needed only for cold starts. In fact, mine only turn on when it's way below freezing (<-10*C). If the engine has been on for at least half a minute, then there is enough heat in the cylinder walls to allow a start without glows, even in cold weather.