Need to install a kill switch

I was trying to think of what component and where to tie in to best implement a "kill switch", a hidden switch where when tripped would not allow the engine to start even with a key. I was thinking maybe the line to the fuel pump but I don't know the easiest access point to that supply wire.

Ideas?

2005 3500

Thanks!

**** Note I have the driver seat out at the moment, installing a door lock mechanism access for my car alarm. But I see nothing other than the computer and I am afraid if I mess with that, I'll get all kinds of check engine codes set that won't be easy to clear.

I've always toyed with the idea of installing a manual fuel shutoff switch in my vehicles, but never done it. Basically a brass (or other) ball valve accessible from the driver's seat, but hidden. Doubt anyone would think to look for that kinda thing, and they wouldn't get very far without fuel....

Yes, killing the starter is kind of silly actually because a thief would logically think "ha, ha, a 30 second challenge" but if some component was failing when they tried to start it, he would be in the same boat as us, saying, what the hell has gone wrong now and how do I fix it.

You can get an electric valve so that you could turn it on easier.
I remember fuses under the seat that would not let the engine run. I ran in to that when I was trying to turn off my DLRs.

Break the line with a switch for the starter relay?

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The fuel pump relay is the yellow one on the driver's seat-side fuse panel.

What i don't know is whether your Sprinter will run without it. Pre-2004 Sprinters didn't have the in-tank pump, and still managed to run by pure mechanical suction from the high pressure pump.



Likewise, opening the SKREEM or Transmission fuse circuits would also disable the van

(you could put the discreet switch on the front of the driver's seat pedestal so it couldn't be easily seen)
((you could put 3 or 4 switches down there, so that only a particular pattern of up/down would work... 3 switches give 9 possibilities, 4 raises it to 16))
(((and each switch could disable a different function: fuel pump, skreem, tranny ... leading to a much longer "puzzle time" for the crook)))

Full schematics are in section 8W of the service manual: http://aie-services-2.net/Sprinter/2006-VA-SM.pdf

--dick

You could just take the starter relay with you?


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How about adding a switch to break the wiring to the brake light switch? Then the engine would start but you would not be able to move the gear selector out of Park (unless you knew the trick with a biro).

I'm thinking laterally from what causes problems with Sprinters! ie brake light switch fails and you're stuck in Park.

Keith.

Thinking outside the box - killing power to the ECU should prevent running. Putting a switch in the crank position sensor line or the cam position sensor might effectively prevent running as well.

Pulling the 10 amp fuse (or installing a switch) definitely disables the SKREEM with a start error on the dash. Might be easier than messing with the starter relay

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Arnie_Oli said:

You could just take the starter relay with you?


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

Click to expand...

This is a Proven method of deterring van theft and has worked for me every time !

ptheland said:

Thinking outside the box - killing power to the ECU should prevent running. Putting a switch in the crank position sensor line or the cam position sensor might effectively prevent running as well.

Click to expand...

I would look at grounding the Cam sensor signal line. It totally prevents engine start. And it also doubles as an "economy mode" switch for after you've started. It puts the engine into a silent limp mode with low boost and short-shifting the trans, saving a ton of fuel. Then simply switch off for full power again, no restart required.

Judging from experiences on the forum, no kill switch necessary, she'll die on her own.

As I think was mentioned previously, my preference would be to disable the fuel pump. Assuming that the thief has done something to subvert the security, a crank - no start situation would have them thinking their method was somehow flawed. No crank at all gives them something to explore further.

Messing with the SKREEM is intriguing, but that can be one expen$ive module should your methods go awry.

My preference would be to stay with a fuel pump signal disable. It's a basic relay so messing with that control signal is pretty straightforward.

vic

Aqua Puttana said:

As I think was mentioned previously, my preference would be to disable the fuel pump. Assuming that the thief has done something to subvert the security, a crank - no start situation would have them thinking their method was somehow flawed. No crank at all gives them something to explore further.

Messing with the SKREEM is intriguing, but that can be one expen$ive module should your methods go awry.

My preference would be to stay with a fuel pump signal disable. It's a basic relay so messing with that control signal is pretty straightforward.

vic

Click to expand...

Reminds me of the other "feature" of disabling the cam signal... It has a 50% chance of firing a few cylinders every time you begin to crank it, until it sees that there is no cam signal on the second phase of 360 deg of crank. The ECU assumes it knows which 360 phase it is in when it doesn't see the cam the first time it could (cam happens once every 720). So it tries to fire up to 3 cylinders until it really doesn't see the cam signal when it knows for sure that it should have seen it on that 2nd phase.

So if the cyls it does try to fire happen to be the correct ones for that phase (a 50% chance), you will get some life out of the engine but then nothing. This is also what makes it hard to diagnose a cam fault, because the ECU tricks you into thinking its a fuel issue since it does actually fire and then stop.

I agree about not touching the SKREEM, it also gives the game away with the "start error" message.

Messing with the SKREEM does not solve any since a thief will bring his own security-less ECU and bypass it.
I would cut a wire to the rail pressure control solenoid in some very inaccessible place and use a relay activated by the brake switch. So it starts and runs until one steps on the brake pedal.

owner said:

Reminds me of the other "feature" of disabling the cam signal... It has a 50% chance of firing a few cylinders every time you begin to crank it, until it sees that there is no cam signal on the second phase of 360 deg of crank. The ECU assumes it knows which 360 phase it is in when it doesn't see the cam the first time it could (cam happens once every 720). So it tries to fire up to 3 cylinders until it really doesn't see the cam signal when it knows for sure that it should have seen it on that 2nd phase.

So if the cyls it does try to fire happen to be the correct ones for that phase (a 50% chance), you will get some life out of the engine but then nothing. This is also what makes it hard to diagnose a cam fault, because the ECU tricks you into thinking its a fuel issue since it does actually fire and then stop..

Click to expand...

The training manuals pretty much say flat-out that "no cam signal = no injector squirts at all".

That's because there's a 50% chance that you'd be squirting into an exhaust stroke ... pumping the fuel right out into the tailpipe and CAT.

The cam sensor tells the engine how to interpret the crankshaft sensor.
The engine will actually run without a cam signal, but it won't start without one.



--dick

I was looking at my Sprinters today. I think that it would be a simple matter to intercept the fuel pump relay signal and install a switch within the seat pedestal.

The position doesn't need to be super secret because it is not original.

My chosen location would be a simple rocker switch tucked in behind the Parking Brake Lever. It would be pretty much protected from damage, mostly out of sight, but easy to reach down to change position when needed.

A white rocker switch would even match my Arctic Whitewash pedestal color.

There are many other possible locations.

vic

Pull fuse 7 or add an in-line switch with this fuse.

OF course, the second step would be to put a small, but obviously owner-added switch somewhere (like below that little cubby hole to the left of the US steering wheel).
Thief enters Sprinter, tries to start it. Your "kill switch" prevents the starter from turning.
Thief looks around, sees small switch. Chuckles because it was so easy to spot.
Flips switch.
The switch activates a "latching relay" (which won't turn off when the switch is flipped back).
*Now* is when the alarms start screaming ... the horn starts blaring (well... whatever you'd call the Sprinter's feeble horn's noise), etc.

enjoy the thought
--dick