If that be the case, why not just install a "damper", on a choke-cable, in the intake tubing, just like goes in the stove-pipe at home??

That way, it would always be there, for just such emergencies.

 

Someone could build one to have when doing these mods and just move it from truck to truck. Good idea.

 

wow, those r some interesting stories! That detroit deal is interesting, im going to have to do some more research on that now.

It is a very good idea to have anything sturdy enough (like a 2x4) handy to shut er down, its a scarry thought just to immagine my motor taking off like a rocket n puking its guts all over the ground, or worse yet, through the side of the block!

 

My dad was stationed in Germany in the late 70's and he was a heavy equipment engineer over there. He had a 2 1/2 ton, but he worked on everything there. Those trucks would use 24v systems (two batteries...huge batteries) and when it would get cold the batteries would reverse polarity. Then when you go to start up, it starts up backwards...no biggy, just kill it, warm the batteries and go. He said it sure was a sight seeing black smoke roll out the big breathers. The reason a fuel shutoff wouldn't always work for runaways is sometimes runaways are caused by oil leaking from the turbo and the engine would run off that, that's why the higher sledpulling classes are required to have a guillotine air shut off before the turbo.

 

I forget where I saw it online, but they sell a "kit" for trucks destined to oilfields that is basically just that.

 

they are called positive air shut off's

 

That is incorrect. Every single time I had a runaway I have been able to kill it with the key and worked fine. I know every truck wont be able to do stop the engine with the key during a runaway condition, but I have been lucky enough to.

 

OK, how on earth does it run backwards???
I get the general idea i think, so now it is running instead of clockwise, its turning counterclockwise? effectivly using the intake for an exhaust, and exhaust for intake??? how the heck does it do that??

 

About like that. Sucks air in through the exhaust and blows the exhaust out the air filter. They don't run very good backwards...

 

The only engines I have ever seen run backwards were the Detroit's and all 2 strokes.
I have also seen them run with the crankshaft broken in 3 pieces because on the Detroit’s the injector is fired by the camshaft and not timed by a pump.

An inline could break into 6 smaller engines and still be running.

There is also a complicated mechanical fuel rack that throttles each injector, if the rack ever binds up the engine can run away also.
When I would set the rack I would always and check my work before I fired the engine for the just in case something went wrong.
Jim

 

Hey yall im new to your site but not to runaways i was workin in a shop, the guy next to me was on an Cumm. M11 w/ a blown turbo. he didn't flush the cooler and on startup it sucked all that oil into the engine he shut off the key and the thing kept screaming once it cleared the cooler and half the oil in the pan we threw it in gear and rode it out it ended up ruining the cam and the block had to be pulled. so moral to my story any preventative measures for a runaway are prob. a safe move, if you fear it. though not to scare you but i have seen a two-stroke detroit run away when i threw my book over the intake it sucked its valve seals in and kept running it finally stopped though after a min. but it felt like a life time

 

Just to add to this a little. I recently had a situation where I turned up the fuel, revved it a few times and it didn't seem to runaway any. Well driving it, it started to runaway at higher RPMs. With a manual, I was able to let the clutch back out, with it still in gear, and apply the brakes to help bring the RPM's back into a range where the pump would let it come back down on it's own. I would think that with a lockup converter in an auto, a similar result could be had by manually shifting and braking.

Just thought this might help some people with manuals or lockup converters to feel a little more comfortable knowing they can save it without getting out of the vehicle.

 

Just another warning from someone that knows to be carefull around the fuel screw. I wanted to try to take my pump to the max but didnt think runaway was that easy to hit. After a slight turn (1/4 - 3/8 turn) I would hit the throttle then make another adjustment. It finally hung a little then came down so I smacked the throttle again and it took off It was revving to infinity and here I am panicking running all over trying to find a scredriver and a board as the motor tried to tear itself appart. At one point I tried to tear the intake off the turbo by hand but I had really snugged it up good. After like 1-2 min I finally get it apart and get the turbo covered up. I was so worried I blew up my cummins I just sat there for like 10min scared to start it up. Seems to run fine now but sounded bad, my tach doesnt have a recal option but I swear it was over 3800. Sounded more like 4-5 grand. So always have the intake apart and a board near by when making serious fuel adjustments.

 

SCARY stuff......I always have a 2x6 and a buddy that has full understanding of what to do and how to do it safe. No finger cutting for me....yuck!

 

I've had good luck turning the fuel screw up with the truck running. With my fingers right on the screw, I blip the throttle and check for floaty behavior, then I slowly run it up to WOT to see if it hangs/runs. On the few occasions it started to get away from me, I simply turned the fuel screw back a bit and she settled right down. This, of course, only addresses a runaway condition caused by the control collar not being able to return to the low idle position due to too much fuel screw tweaking. Another fuel source (oil from a turbo seal, etc) will require the air to be shut off somehow.