Is it possible for a 6.2 to runaway, safety measures?

[iacucv]

I am fairly new to diesels and have learned a ton from you guys, many thanks for my saved dollars and healthy 1008. I'd known about the runaway diesel concept but hadn't thought of it happening to my cucv till just today. I'm still pretty unfamiliar with the IP system used on these engines, so is it possible for this to happen?
If it is possible, is there a safety measure anyone can recommend, such as a dash mounted fuel line shut of valve of some sort? Thanks for your guys thoughts.

 

[CycleJay]

Hello,

I do not know if that type of runaway issue can happen with a 6.2 in a CUCV.
But in CUCV's, the starter relay can become stuck open, and make your starter runaway, until it burns out.

So the best way to stop that from happening is to replace the stock starter relay with a different one,
by doing the "Doghead starter relay modification" that is mentioned all over Steel Soldiers here.

I have done that mod myself in my M1009 after replacing a starter that had runaway and burned out,
and since then, I have never had that problem again. So save yourself a lot of money, grief, and agravation,
and get it done, it is not hard to do, so you should be able to do it yourself.

Just my $0.02 cents...

Good luck, and good night...

 

[firefox]

I'll second the above. This is a MUST DO. The relay is now made in China, and
I already went thru 2 of them. Luckily it didn't stick closed. Don't put this
off. The amount of damage that is done is really bad.
Bruce

 

[cpf240]

Once running, a diesel only needs fuel and air. On the 6.2l used in the CUCVs, there is a fuel shutoff solenoid on the IP. If this solenoid failed in an "open" position, there would be no way to shutoff the diesel. One thing you can do would be to place something rigid over the intake and "smother" it. I suppose you could pinch a fuel line with something like vise grips, or perhaps open up the bleeder screw on the filter and see if enough air can get in the lines to stop it.

The bigger problem with runaway, at least as I understand it, is that some vehicles can get stuck at wide open throttle, leading to a blown engine. Unless the linkages are binding, I don't think that is much of an issue with the CUCVs.

This is one of the reasons the military wants the wheels chocked, to prevent a vehicle from rolling and starting on its own if bumped vby another vehicle.

 

[richingalveston]

The only way to stop a diesel is to remove the fuel input. As far as getting it to go faster, the only way to do this is to increase the fuel input. The only way the cucv to start is by having power to the IP and the motor spinning fast enough. Due to the auto trans, you cannot push start it unless you have 4 or 5 to one reduction on the transfer case and a really steep hill. So your engine will never start by itself and take off.
If your your engine was running and your IP shut off solinoid was stuck open and your throttle stuck wide open then yes, technically you could not stop it other than putting it in neutral and letting the engine over rev until it blows.

The odds of all of this happening is extremely remote. So remote I do not know of any documented cases where this happened. You would pretty much have to purposely cause all of the above issuse to happen to make it run away while driving it.

 

[iacucv]

Doghead mod was done as soon as my 08 got home, as well as new belts and general maintenance. I am familiar with the general flaws on the cucv, only focus of this thread is the potential of a runaway diesel as pertains to fuel/air delivery and not being able to shut it down.

cpf240 addressed some issues. The IP has solenoids to prevent the problem, but parts fail. And to stop a RAW diesel you have to pinch a fuel line. This could be very dangerous with it screaming above redline ready to blow.

has anyone considered or implemented a fail safe engine kill, maybe a very simple valve in the fuel line that can be actuated from the dash? Even a bit of shrouded cable and an e-brake/hood release type switch connected to a manual valve could save the engine. Could also be a helluva cheap, easy, and inconspicuous theft prevention lol.

 

[m16ty]

Any diesel can run away. Some are more prone to it than others though. I'd say electronically controlled engines are the least likely. 6.2 engines aren't particularly likely and I've never heard of it happening.

Any mechanical IP has a governor inside and that governor can stick. Most often problems happen after a engine has been sitting for a long time.

I just had a Ford diesel in a military forklift run away with me this week. I was prepared and quickly snuffed it out before it got out of hand. The governor inside the IP was stuck.

 

[TGP (IL)]

I am fairly new to diesels and have learned a ton from you guys, many thanks for my saved dollars and healthy 1008. I'd known about the runaway diesel concept but hadn't thought of it happening to my cucv till just today. I'm still pretty unfamiliar with the IP system used on these engines, so is it possible for this to happen?
If it is possible, is there a safety measure anyone can recommend, such as a dash mounted fuel line shut of valve of some sort? Thanks for your guys thoughts.

Any Diesel can run a way as mentioned.
Very seldom it will happen from it's own fuel source.
It happens when a Diesel idles for extremely long periods of time and slobbers in it's own oil to the point were it gets into the air intake system.
Then the engine ignites this oil and has a new ignition source. It no longer need fuel and runs away.
The only way to stop it, is to smother it out by blocking the intake air.
Also can happen if the engine can draw contaminated air with fuel vapors in it,ie refineries, fuel storage lots, etc.
There are kit's available to install a intake butterfly valve to smother the engine.
Could possibly modify one for our application.
Do a Google search.
Tom

 

[Matt65]

My plan for a runaway Diesel would be to discharge a fire extinguisher into the intake, smothering the engine. All my vehicles have one on board. I've never had to use them for this.

 

[doghead]

The only way to stop a diesel is to remove the fuel input.

That is one way, not the only way.

 

[MarcusOReallyus]

The only way to stop a diesel is to remove the fuel input.

Two other folks have mentioned smothering it. It's not difficult. I've done it myself on a Mercedes belonging to a friend of mine. I've seen military mechanics and other soldiers do it with M113A1s.

My plan for a runaway Diesel would be to discharge a fire extinguisher into the intake, smothering the engine. All my vehicles have one on board. I've never had to use them for this.

I hope that's a halon or CO2 extinguisher. A powder type would sure make a mess of an engine.

 

[Skinny]

Won't it take a while for the IP to run out of fuel by crimping the supply line? I read somewhere on here that pinching the return line will cause a spike in outlet pressure and slow the engine to a hault. Never tried it, unconfirmed by me. Theoretically as long as your shut off solenoid works and didn't get stuck open by taking the pump apart, pulling the pink wire to the IP will shut the whole thing down.

Run away diesel...sounds like a bad day at the office!

 

[caliber1]

An old mechanic I used to know kept a hammer close by when starting an unknown engine. Asked why one day, he said it was to knock the fuel line off the IP. Just break it off. The older Detroit 8Vs had a big cast aluminum plate over the top of the blower opening, that was the emergency shut down. A solenoid would release that plate and cover the intake.

 

[73m819]

1--- Any deisel can run away (some gassers with a LOT of carbon will also)
2--- A turbo death is a GREAT fuel supply, this can be instent run-away
3--- A machanical fuel pump death is another great fuel supply (puts fuel in the oil, as the oil thins and level rises with crankcase pressure building, it gets past the rings and valve guides/seals and becomes FUEL). A major pump death can happen VERY guickly
4--- A MALFUNCTIONING mechanical governor can (in fact any governor can) cause a instant run-away
There is a few other fuel supplies that can cause a run away but not as likley

 

[73m819]

An old mechanic I used to know kept a hammer close by when starting an unknown engine. Asked why one day, he said it was to knock the fuel line off the IP. Just break it off. The older Detroit 8Vs had a big cast aluminum plate over the top of the blower opening, that was the emergency shut down. A solenoid would release that plate and cover the intake.[/QUOTE]

This sometimes just sucked oil past the blower seals which in turn was MORE fuel to burn and caused the motor to suck air AROUND the emg. shut down plate and any where else that air can be sucked.

 

[91W350]

I had a short lived run away on a M1009, I was changing oil and air filters on all three CUCVs and my son volunteered to help me. The replacement filters did not come with new foams, so I rinsed the old ones in solvent and then blew them dry with an air hose. My dry and my son's dry were entirely different. He left the foam fairly wet, the engine took off and raced on the solvent, until it sucked the source dry. I turned the switch off immediately, but it ran for 15 to 20 seconds before starving itself. Pretty spooky when they are going like that and you do not understand why.....

 

[Evil Dr. Porkchop]

The other reason to have the tm in the glovebox is to block off the air intake with it!

 

[Ken_86gt]

I once unintentionally induced a slight run away condition- I was cleaning something in the engine bay with carb cleaner and the engine was running. The fumes in the general area were enough for the engine rpms to pick up. It was very minor but I was not expecting it.

If you have a fuel solenoid failure (stuck open) the engine could theoretically continue to run- but this is not a run away out of control situation as the throttle would still be controlling the engine speed. You could then take your time to decide the best way to stop the engine.

 

[ajsmith184]

I had never really thought of this until my ignition switch came apart when I went to shut it off....My initial reaction was somewhat panic, but I was able to jostle it around and get it to shut off...then went and got a new ignition switch

 

[Barrman]

A non runaway but not shutting off 6.2 is easy to kill by pinching the return line at the top of the IP. This is in reply to the last few post about ignition switch issues. It won't help with contaminated air supply run away issues.