How can I rig up a manual shut-off switch? - PeachParts Mercedes-Benz Forum

Rather Diesel · #1 08-28-2008, 08:13 PM

I need to shut off my 300TD engine without opening the hood.

Any suggestions on how to set up a vacuum switch to shut off the IP when the ignition switch is turned off? All the factory solenoids, switches and relays were removed prior to getting the engine. And, I don't want to buy $$$MB parts if I can avoid it.

Thanks

tangofox007 · #2 08-28-2008, 08:49 PM

You don't necessarily have to use vacuum. A mechanical means might be easier. Possibly a Bowden cable or even a pull cord. Are you using vacuum for anythng else?

LUVMBDiesels · #3 08-28-2008, 09:14 PM

You need a shut off valve on the IP and a shut off switch connected to the key switch.

I have a working shut off valve i will let you have for $40. The switch is ~20 bucks from Fastlane. You will also need two gaskets for the valve. PM me if you want it.

bgkast · #4 08-28-2008, 10:36 PM

Run a tube to the cabin and suck on it.

kerry · #5 08-28-2008, 11:23 PM

Quote:

Originally Posted by bgkast

Run a tube to the cabin and suck on it.

My thought exactly. I've done it myself but never bothered running it into the cabin, just ran it out under the hood at the cowl.

moon161 · #6 08-29-2008, 01:00 AM

I would not rely on vacuum for this. If you had vacuum, why would you use the shutoff? I'd use a cable like for a lawnmower/aircraft throttle. $6 at autozone. Pimp it out, run it to the dash, screw a pool ball on the handle, #3 or 5 for visibility, or #2 cause if you're using it, you've probably gone #2.

JimmyL · #7 08-29-2008, 01:12 AM

If you can't repair something as basic, simple and necessary as the vacuum shutoff for these cars then you need to sell it and buy a Yaris. {with warranty}
Please.......

pawoSD · #8 08-29-2008, 01:14 AM

Quote:

Originally Posted by JimmyL

If you can't repair something as basic, simple and necessary as the vacuum shutoff for these cars then you need to sell it and buy a Yaris. {with warranty}
Please.......

I completely agree. The vacuum shutoff is about as simple as it gets.

1. Vac source to a valve. (key switch or your own valve, use an aquarium valve if you want.

)
2. Valve opens and lets vacuum down second tube to shutoff
3. When vacuum reaches shutoff it turns off engine.

Not exactly complicated.

tangofox007 · #9 08-29-2008, 06:18 AM

Quote:

Originally Posted by JimmyL

If you can't repair something as basic, simple and necessary as the vacuum shutoff for these cars then you need to sell it and buy a Yaris. {with warranty}
Please.......

From a previous thread, the OP is installing a 617 engine in a truck. So some of the simple and basic components (like an ignition switch with a vacuum valve) don't exist.

A little perspective:

Quote:

Originally Posted by Rather Diesel

...I am trying to minimize the complexity of the engine in any way I can.
...I should probably add, that this engine is being mated to a Toyota manual transmission in a base model truck, so I'm trying to get rid of all auto-trans related items no longer needed. Every sensor, vacuum line, switch, linkage, etc. that isn't required is going to go.

H-townbenzoboy · #10 08-29-2008, 03:15 AM

Quote:

Originally Posted by moon161

I would not rely on vacuum for this.

Why not? It worked fine for MB since the mid 70s.

#11 08-29-2008, 03:45 AM

Quote:

Originally Posted by H-townbenzoboy

Why not? It worked fine for MB since the mid 70s.

70's to mid 90's all across the world. If you have any vacuum source, there really isn't a good reason to abandon such a simple working design.

bratwurst · #12 08-29-2008, 03:06 AM

I had to do something similar with my G class.

The shutoff valve is at the rear, bottom area of the injection pump. If you apply vac to the valve, the engine will stop.

Easiest way to control the vacuum is to use a vacuum solenoid. The previous suggestion of sucking on a vacuum tube might work, but it didn't for me (I tried!).

I went to wrecker and found a vacuum solenoid from a VW fox; they seemed to be the easiest to pull out. Then it was just a matter of connecting the vacuum solenoid to a switch and power, as well as vacuum.