stopping the motor or a run away
 

I have been reading about my new old car for a couple hours for the past few days. I keep hearing about a stop lever to kill the motor if it runs away or if the vac fails to stop the motor when you turn off the key. Where is that located?

I like the CO2 idea. I think I need to find one to keep handy just in case.

On the 240D OM 616 there's a lever marked STOP on the driver's side of the engine above the injection pump on the linkage

On the older OM 621 cars, pushing the throttle rod inward will stoip it.

I keep a rag the size of two wash cloths around when firsat running diesels of unknown condition in case throttle linkage gets stuck.

Throw it in the air intake or block the air cleaner. NEVER NEVER NEVER USE YOUR HAND.

Ill have to take a closer look at it this weekend and see if I can spot it.

This is where it is on my 300D. Sometimes the paper tag is gone or unreadable.

Other methods to stop a runaway involve as the other member said is blocking the air inlet, using s CO2 fire extinguisher (not the dry powdered ones) directed into the intake to deny oxygen to the Engine, and clamping or cutting the Fuel supply Lines (this can still leave enough fuel in the system to let the Engine run a bit).

Blocking off the air is fast and the surest method. However, it has to be planned (you need to disconnect the cold air duct/tub) for unless it is an Engine like a Detroit Diesle that has an emergency shutoff or an Engine that has a compression release.

An unplanned for runaway can be delt with by yanking/cutting off the rubber supply hose but the Engine still has a filter full of fuel to run through.

Both of the above are easier if the Hood is already open.

The STOP lever is useful in the event that a loss of vacuum prevents normal shut off. It will NOT, however, stop an engine that has run away due to injection pump maladies. I have tragically been there, done that. End of story.

When starting a diesel after injection pump work, hold a 17MM wrench in one hand when the engine is started. If it runs away, crack the lines at the injectors one at a time until engine dies.

STOP RIGHT THERE!!!!!!!! Don't start talking about cutting the lines, pulling the fuel line, loosening the fuel filter or any of that other stuff!!!!!! Have a 17MM wrench in your hand and loosen the injector lines at the injectors. AGAIN, BEEN THERE.......... DONE THAT!!!!!!!!!!!!!!


To make sure that definitions are made, a run away engine is NOT one that fails to shut off when the key is put in the off position and continues to idle. That is just an idling engine that has a problem getting stopped. A RUN AWAY engine is one that is setting there getting MAXIMUM FUEL RUNNING AT MAXIMUM NO LOAD SPEED! A RUN AWAY engine must be stopped and immediately. The best way to do this is with a 17MM wrench in hand, loosening the injector lines at the injectors one at a time until the engine is dead.


Did I mention that you should have a 17MM wrench handy when starting an MB diesel after injection pump work?????

Also a run-away can be when it is feeding of it's own crankcase oil, staving it of air is the only way . . . well . . . it will stop on it's own, but it will be in all apart . . . C02 is very bulky & VERY expensive, google it!

So I take it by cracking open the injector lines you are removing the pressurized fuel from the injector keeping that injector form firring? This would cause some fuel to drip down the side of the motor correct? Of course fuel on the motor is better then a frozen motor after it floats a valve or kills a bearing!

How much pressure is in those lines when the motor is running?

124.128 "Runaway" stopper
 

1.Have Halon fire extinguisher,Handy.
2.Operate Halon Fire Extinguisher into the five "Gill" slits of the Air Intake in the
right front(Forward) fender.

'Works with Hood Open or Closed.

Halon is an inert gas, so no messy residue anywhere.

The turbo engines run about 2000 psi.

Don't worry, yes there will be diesel running out when you crack the lines, but it will only be a dribble. Only crack the line enough to relieve the pressure. A half turn should do it. There will be no mess to clean up.

That's just the pop pressure. As the IP piston rises, the flow increases dramatically, increasing the pressure to well above the pop pressure as the fuel is forced through the small opening.

I thought it was more like 15,000 PSI. The VW PD TDI runs at 29K PSI. I don't know what a CDI runs, but it's up there too.

So I guess you're saying have a 17 mm wrench handy to crack the lines open at the injector!!!

I agree. BTW, proper SI (metric updated) units are mm for millimeter. The prefix milli (m) = 0.001. The prefix M (mega) = 1,000,000. We could all park our cars end to end between the wrench faces of a 17 megameter wrench!!! LMAO

Even at Full Throttle there is not that much Fuel Volume. So there is not going to be a big puddle of fuel.
Also if you manage to loosen all of the Hard Line Nuts it will stop quickly.

The problem is it takes some courage to remain calm an loosen all of the Hard Line nuts while the Engine is screaming.
And, when they throw a Rod it comes out/through the side of the Engine Block.
Also in the case of a Runaway caused by a Fuel Injection Pump Jammed at full Throttle before you can say Oh Shi* the Engine has maxed. If the IP Governor is working and set correctly It sould not go above a certain RPM.
In the 78, 300SD book that RPM is 5100.

Note the standing there with a 17mm wrench or being ready to block off the airway requires that you plan ahead.

Careful with Halon it confined spaces. As you said it is inert it has no Oxygen in it at all. Do not breath it in.

Back in the 1980s 4 Sailors were killed at the San Diego Shipyard due to the Halon Fire Extinguishers in the small space they were in being set off. It displaced the Air.

When flow increases "dramatically"...........pressure falls.

In this specific case, I'm doubtful that the pressure rises much above the pop pressure. The amount of flow is very low per stroke and the restriction of the injector is not significant compared to the quantity.