I'm still betting that someone installed an electric fuel cutoff instead of fixing the vacuum system and that it is malfunctioning. I can't think of another explanation that doesn't involve magic.

As Kerry suggests, this is you next move. I believe you will find that once you pull the brown vac line off the shut off valve, your sequence of turning the key back and pushing the horn will no longer kill the engine. If that is true then your problem is in the altered ignition assembly.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

There is one insane thought that arose. Are you saying it has to be the horn button? If you press with the same pressure just near the horn button the engine keeps on running? It is quite a leap if this is so.

The linkage from the key to the vacuum portion of the switch is a straight mechanical process. What electrical event could boost the swing of that mechanical linkage is really wild in a switch. I hate to use the word impossible as that will occasionally backfire.

It is difficult but not impossible to set up a remote start system on these diesels. Primarily because of the glow plug function interval before cranking. It would take a more complex than normal arrangement.

If you have a friend or aquaintance who is familiar with these specific cars you might want him to have a look for anything unusual in the system.

Hopefully the test of pushing beside the horn button with equal pressure will result in a shutoff as well. If not in my opinion a very hard look around is going to be needed.

If craig is right, that solenoid would have to be in the fuel line, probably down near the primary filter. Look at where the rubber line comes off the metal line and heads towards the lift pump and injection pump. There should only be a plastic filter in that line between the metal line and lift pump. If there's something else, ie, an electric solenoid cut off, then craig is correct.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I guess pics are in order to determine if Craig is on to something. Can you pop the hood and take some pics for us?

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

I agree, that some photos of the fuel lines under the hood so we can see if something was added. If not, I'm pretty much stumped.

If then shutdown occurs quite fast with the horn button it has to be the vacuum is being affected.. Any form of shutting off the fuel supply before the injection pump would take time after implementation for the engine to quit.. .How much I am not sure of because of many things but enough to be irritating I would suspect and the poster would have reported the delay.

You would be looking for an unusual device installed in the vaccum line in this case. . That is a really unlikely thing as well. Just my opinion of course.

Nothing else other than the pressure on the area for practical purposes makes much sense at this point.

At this point I really still hope that the same pressure applied to an area close to the horn button kills the engine as well.

Since the engine runs and does shut down it does appear the vacuum valve is basically intact..Or maybe the impact from hitting the horn just moves a loose valve in the switch.

I think an electric fuel shut off solenoid would cause the engine to shut off promptly. That's all my CAT 3208 has on it and there is no delay. As soon as the valve activates, the lift pump won't operate anymore and no fuel can be delivered to the IP.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sorry Kerry I thought there might be a delay caused by the residual pressure dropping off in the injection pump. On consideration the pressure drop is instantainious as it is a hydralic system with no retained pressure generated by a compressed air component expanding.

So as you stated a fuel cuttoff solinoid as early in the system as the primary fuel filter could be as quick as the factory system in shutting down. I still think there might be a little run on with an in line piston pump over another design of injection pump or a ragged type drop out. But who really knows.

If this is not a pinched vacuum line or a vacuum switch not fuctioning properly it will be one for the books. I suspect he really hits the horn button. Not just gently activating it. Shaking and moving everything pretty good.

Unplug the horn wires from the horn(s) and see if that has any effect.

When I transplanted a 2.2D motor into a W201 2.6 gasser body, I used 2 electric operated valves on the vacuum line to the IP shut off. The IP turns on and off with the electric signal from the ignition switch.

When there is power to the valves, the vacuum circuit is open to the air so no vacuum is applied to the IP's shut off. When the power to the valves is turned off, the valves allow vacuum into the IP's shut off circuit.

Key on : vacuum to the IP shut off is released
Key off : vacuum to the IP shut off is applied

If the car lived in a cold climate where the owner may have wanted to leave it running with the key out and locked up, they could have made a circuit that simply used the horn to ground the valve control.

__________________
Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

people my apologies for the delay i was gone the whole day becuase of soemthing came up with my son..tommorow i will take pictures and post also will try troubleshoot..like i said i banged on the wheel everywhere pressed the wheel..but only when i press the horn it cuts off and i dont have to hit it hard ..it cut right the heck off with no delay as if i was hiting the the off switch on the engine that i have to press everytime to stop the car..what i found odd like i said this morning it didnt do it it cut off normal for about 5 times and thats a first..then when came back out shortly after with my dad and the horn would only cut it off i did that repeatly like 5 times or more

thanks alot you guys are very kind

This is the best post I've read in a long time.

No. Thank you!

__________________
mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

disconnect the warning buzzer relay and try again

did the same thing this morning worked like 5 times normally then back to having to hit the horn in the off position to cut it off, im taking my son to school be back in a hour will try get good picture once the sun hits on it little better..will try unattach the line to the cut off valve you guys said that is the brown one?? like i said im just learning all this and my injured friend should be back monday who is the brains