Somewhere buried in the posts from the last 9 months is empirical proof that stopping the flow of fuel into the IP (by cutting, removing, or clamping the fuel line) will stop the engine quickly. It was proven by accident by one of the forum members. I believe that what happens is that without fresh fuel for the pump to use, it is unable to compress the fuel in the pump to make the engine run.
All theory aside, empirical proof prevails.

Here's the thread:
1985 TD /none starting

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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

Thanks for sharing.

At White Motor Company in Dallas all our tune ups and engine rebuilds and pump replacements were fired up in the chassis dyno room. Most big rigs had decompression releases for emergency engine kills but for those that didn't we had 30 pound CO2 fire extinguishers. Stuck or broken MFI pumps were the common cause of our runaways but oil being fed into the intake, by any means, was the second most common cause. It only took about ten seconds to kill the engine completely but that's a VERY long ten seconds. Pulling the Jacob brake would work also if the engine was equipped with one.

My only close encounter, so far, was with twin 3208 turbo Caterpillar engines in a 70 foot Striker yacht. Freshly rebuilt engines with factory rebuilt MFI pumps. No extra room in a small boat's engine room with only twenty six inches between the engines. Port engine fired up nicely and went through the ten minute run in procedure. The starboard engine fired nicely but when the throttle was opened fully and released, the spinning weights on the pump governor broke and the engine ran away. I got the halon extinguisher jammed into the turbo intake and the engine died in less than ten seconds. Good thing too... no place to run. I do enjoy a good adrenalin rush now and then

Man, I'll find my thrills another way. Down in the engine room with a runaway diesel sounds super dangerous. Glad you got 'er stopped...

Cheers,

Bill

Howdy -
I don't usually monitor this forum but was directed here after posting a note on the "diesel list" asking how to safely re-start my 78 240D after replacing the vacuum shutoff valve this weekend. Someone suggested I read this thread and here I am.

I was going to loosen the fuel lines so I could yank them off but I see that's not fast enough. I have removed the top cover on the air filter and gotten a large towel ready also - which looks like a good idea. Now, before starting it I'll get the wrenches needed to un-do the fuel lines between the IP & injectors -- thanks to the comments here! Even though I followed the instructions in the factory workshop manual by checking that a plug gauge (a long handled allen wrench) inserted into the lower right bolt hole moves in & out as I press the STOP lever - operates the same before and after installing the new valve.

I'm hoping my re-start will be less traumatic than Larry Bible's - to whom I send my sincere sympathy ....

Thanks for the help guys!
Another Larry - hopefully with better IP luck.
78 240D

What I did, (thankfully it wasn't necessary) is I set 2 small vice grips carefully on the nuts connecting the fuel pipes to injectors. They will stay in place so if engine starts and overruns I can't mishandle or lose the 17mm wrench, I could just grab the vice grip and give the nut the 1/3 turn necessary to relieve the pressure.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Another idea I have heard is to connect the new shut-off but leave the bolts loose. Then test it by drawing a vacuum on the shut-off. It should move the plate toward the IP if you have it connected properly. Tighten the bolts.

Makes sense to me.

I don't think I would use a towel. I would take off the air cleaner and have a sold plate or block of wood that would fit over it in case it went WOT.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

As rs899 said, "DON"T USE A TOWEL" It will get sucked into the intake manifold. You will be unpleasantly surprised as to how much sucking force a Diesel engine can develop. Definitely be prepared to use something solid, such as a tin can, or a board. Alternatively discharging a CO2 extinguisher into the air intake will also do.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Howdy --
Now that I've read the posts that appeared after I sent my comment - it appears I can stop my engine *if* it starts to runaway. But, to be safe, I'll have a wooden cone to put into the intake which should stop the air. BTW, I've seen people say that a runaway engine can get to the point where oil in the crankcase will get drawn past the rings and kept the engine running for a while. Ain't THAt a hoot??!! If it's true.

Anyway - I now have 3 things to prep for - keep a wrench handy to loosen the injector lines, make ready to disconnect/cut the fuel feed to the IP and be ready to choke off the intake air.

BTW, Someone mentioned putting their hand over the intake. I think I read that this was a major bad idea which could result in serious injury to the hand because of the vacuum pulling on the hand. Now, since a diesel (as we all know) generates so little vacuum as to need a vacuum pump to operate certain systems - so maybe that's one of those ideas that sound plausible - but I wouldn't take a chance...

Thanks for all the great info! I'll hopefully try to start the engine today -

Larry 78 240D (283K)

A towel put over the intake of a diesel spinning at 5000rpm won't even blink. The towel will be transported to the rear of the car, where it will appear as dirty confetti behind the tailpipe.

Use one of the fuel cutoff methods mentioned. The CO2 extinguisher is great but not everyone has that available.

:p

[QUOTE=LarryBible,
I started the engine on my daughters 300D this morning. I had just put a used IP on it and charged the battery over night. I bled a few lines and it wasn't too hard to get started.

When it started, it went to maximum RPM. I turned off the key, but it didn't shut down. I pulled the linkage all the way to stop, but it kept going wide open. I knocked the link from the upper linkage to the pump loose from the upper linkage and pulled the link as far as it would go, still nothing.[/QUOTE]


After reading this post it's rather enlightening. What caused the runnaway IP? How would Larry have known that this was going to happen? Is it just a bad IP?

Yeah putting your hand over the intake might not be so good. Using a piece of wood would be better. I like the "cone" wood idea.

Incorrect installation of the new vac shutoff pod.



Because it's happened to others in the past, it's a known risk with this job.



No.


BTW - this is only a serious concern for the OM61x engines. Your SDL has an OM603 engine. For the OM60x engines, note the external stop lever range of movement *before* taking things apart. When done with the job, apply vacuum to the pod. The lever should move through the exact same distance as it did before. If not, take it apart and re-do until it the lever travel is the same. The 61x engines don't have an external lever to observe when vacuum is applied, hence the problem Larry had...!

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Dave
Boise, ID
Check out my website photos, documents, and movies!

OK, I've gotten some info from the Diesel List for a method to confirm the vac shutoff valve is installed correctly. Leave the bolts loose and apply vacuum with a Mityvac or by sucking - if installed properly the vacuum valve will pull itself against the IP body and the Stop Lever will move somewhat.

Also - if anyone wants a good way to stop intake air - my sailboat keeps soft wooden plugs next to each thru-hull fitting so if a fitting were to break the plug would be handy for driving into the hole. Plugs are available from Marine vendors like West Marine at 3 or 4 assorted plugs for less than $10.

But I'll still be ready to open the fuel lines to the injectors - which should stop all fuel feed pretty quickly - but I'll insert the soft plug 1st to slow or even stop the engine.

HTH,
LarryT 78 240D

I-turn 9, I know the subject has been exhausted here, but when you install that shut off, if it is the same as the shut off on my 78 300D, you should be able to install the hook and turn it, then carefully pull it out. You should feel it catch and feel a little springyness to it. On most you can feel the manual shut off on the IP wiggle at the same time. That means it is hooked into the fuel rack instead of pushing it wide open. Which results in disaster.

Larry,

I feel so bad for you; wish I could fix it ...... And many thanks for your recent help to me ----- I am enjoying the dash lights ... the flashlight bit gets old in a hurry.

Ed S.

A Co2 fire extinguisher is the best way to kill one or for our cars a heavy block of wood that you try before hand and make sure seals. Anything flimsy will be sucked right in, larger diesels can suck your arm in! Imagin a 16v-92 running away!

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200