Can M35A3's runaway?

[1 Patriot-of-many]

Geez after reading a bunch of posts on runaway diesels Am I getting in too deep here?

I've been driving tractor trailers for about 20 years and frankly I've never heard of a diesel running away. Guess I live a sheltered life

Is a runaway more prone to the Detroit or is it universal with these MV's?

 

[patracy]

If it's a diesel, it can runaway.

Well some of the new diesels have butterfly valves for emissions (EGR'ed trucks mainly), I'd assume there's some logic in the ECM that would close the valve in an overspeed situation.

In the case of the CAT engine in your A3, it certainly can.

 

[3dAngus]

Geez after reading a bunch of posts on runaway diesels Am I getting in too deep here?

I've been driving tractor trailers for about 20 years and frankly I've never heard of a diesel running away. Guess I live a sheltered life

Is a runaway more prone to the Detroit or is it universal with these MV's?

I'm not sure what you're referencing when you say runaway, but I'll chime in with what I know. The M35A3 does not have a "Park" in it's automatic like a car or truck, and it is manual so you cannot shut it down in 1st or Reverse, let out the clutch, and use the tranny to "lock er down" like most manuals. You rely on an emergency brake, called a parking brake in the tech manual.

If not on level ground, and the parking brake is not adjusted out properly in accordance with the tech manual, ie. run engine up to 2000rpms and adjust brake adjustment on top of handle, then the truck is subject to rolling away, especially if you are not familiar with proper procedure, or just negligent, and you don't chock up the tires properly.

Yes, the M35A3 can run away in this manner, especially with engine running and it not locked down properly. But if you follow proper procedures, have your vehicle parking brake adjusted appropriately, there are no problems.

If this is what you're referring to by chance, then no, you are not in over your head. Just read the operators manual on the M35A3 and follow procedure.

edit: just read Patracys post. I guess I don't know what a runaway is. Please explain the detail of what happens with a runaway. Thanks in advance.
BTW, the post above was written because I just saw a Deuce today that ran away from its owner because of the text written above. It came within a foot or two of clobbering a big oak tree. Ran away from him about 75 feet.

 

[NDT]

One bizzare reason for a diesel to run away happened around here a while ago. A truck was unloading LNG and a leak developed with a resulting gas cloud. The gas made it to the engine air intake and that truck and another near by "ran away" until both engines disintigrated. That caused the gas to explode and several drivers were killed.

 

[dittle]

3dAngus,

What they're referring to is when the engine goes wide open and you have no control of it. Yes it can and does happen to diesel engines.

 

[dragonwagon]

Actually the old school det diesel had an air shut off to prevent this . Normal shut off killed the fuel , then the emergency kill closed off the air intake .

 

[3dAngus]

3dAngus,

What they're referring to is when the engine goes wide open and you have no control of it. Yes it can and does happen to diesel engines.

Thanks for the technical help dittle.

And I guess you could not shut off the fuel with the fuel switch on the panel while going down the road, as that would probably be just as bad.

 

[Chief_919]

Thanks for the technical help dittle.

And I guess you could not shut off the fuel with the fuel switch on the panel while going down the road, as that would probably be just as bad.

Usually a runaway is caused by a fuel sorce entering it from another point.

Typical causes are bad turbo/blower seals that will leak oil, bad enough and the engine runs on oil.

I have seen it happen a few times. Never fun. I saw an M35A2 do it when the FDC started leaking and into the crnakcase, then the turbo seal blew and started blowing oil/fuel mix into the intake.

 

[F18hornetM]

Sure its possible for a diesel to "runaway" but I gotta say, Ive worked as a technician for going on 30 yrs and I never saw one do it. 23 yrs in my current job watching over 450 pieces of equipment, which by the way use to be mostly 8.2's detroits, 7.8 fords, then Cats-3208's, 3116's, 3126's , then C-7's and so on....now lots of IH's...non ever ran away. so yeah can happen, but just dont think it happens often and with well maintened equipment an trained technicans doing the repairs, doubt it hardly ever happens. If doing the work yourself, My thoughts are if you follow the TM's/service manuals, and Im new to MV ownership, but not new to diesels, then you would be fine. Anything can happen, but In wouldnt loose any sleep over it. just my 2 cents worth

 

[patracy]

There's two types of runaway. The ones mentioned where an alternative fuel source (oil leak into intake path, combustible gas entering intake path). Then there's likely what 3dAngus is thinking about. When a fuel rack sticks and the throttle stops responding. I've had a few VE pumps do this to me before. Usually they don't rev any higher than the governor allows. But still it's not fun to have happen. I had it happen once on my VW diesel engine in my samurai. I knew it would be an issue since I was shimming the governor to allow it to fuel in the 4-5K rpm range. I built my "kill stick". While the VW diesel can handle that RPM stock, I know it hit 6K or better just by the sound.

 

[patracy]

Sure its possible for a diesel to "runaway" but I gotta say, Ive worked as a technician for going on 30 yrs and I never saw one do it. 23 yrs in my current job watching over 450 pieces of equipment, which by the way use to be mostly 8.2's detroits, 7.8 fords, then Cats-3208's, 3116's, 3126's , then C-7's and so on....now lots of IH's...non ever ran away. so yeah can happen, but just dont think it happens often and with well maintened equipment an trained technicans doing the repairs, doubt it hardly ever happens. If doing the work yourself, My thoughts are if you follow the TM's/service manuals, and Im new to MV ownership, but not new to diesels, then you would be fine. Anything can happen, but In wouldnt loose any sleep over it. just my 2 cents worth

Very good point. Mine was self inflicted.

That's also why I pulled back home in my deuce yesterday when I saw tons of smoke on decel. I knew I was likely dealing with turbo seals. 40-60psi of oil into the intake path =

 

[F18hornetM]

Usually a runaway is caused by a fuel sorce entering it from another point.

Typical causes are bad turbo/blower seals that will leak oil, bad enough and the engine runs on oil.

I have seen it happen a few times. Never fun. I saw an M35A2 do it when the FDC started leaking and into the crnakcase, then the turbo seal blew and started blowing oil/fuel mix into the intake.

I only have 4 years experince driving A2's, non working on them untill now. During those 4 years never saw one run away, lots of years working on 3116's, and saw non run away...i too must led a shelterd life..ha ha and would like to keep it that way, cant be a good thing when it does.

 

[F18hornetM]

Very good point. Mine was self inflicted.

That's also why I pulled back home in my deuce yesterday when I saw tons of smoke on decel. I knew I was likely dealing with turbo seals. 40-60psi of oil into the intake path =

You made me think of something after my replies. these engines are often over 40 yrs old, so issues with turbos and such are more likely, than the trucks we use for commercial work today, where the oldest truck is only 12 yrs old..so yeah i can see it.

 

[Dave08]

I have seen this happen once with a Detroit in a LVTP7. The runaway happened where the diesel fed itself on its own oil. Everything was tried to include fuel shut down and the engine continued to rev out of control. It finally blew and threw a rod out the side of the AmTrac. No one was injured but the power pack and engine compartment were a total disaster. It took the depot level guys to repair that one.
I have never seen it happen in any of the diesel trucks. This is not to say that it can't happen just that I have never seen it in the 809 or 900 series 5 ton diesels.

You are not getting in to deep and for the most part really do not have to worry about this type of thing happening if the proper maintenance is performed on a regular basis.

Dave08

 

[midcounty]

One bizzare reason for a diesel to run away happened around here a while ago. A truck was unloading LNG and a leak developed with a resulting gas cloud. The gas made it to the engine air intake and that truck and another near by "ran away" until both engines disintigrated. That caused the gas to explode and several drivers were killed.

A couple of years ago there was a similar accident in Berlin MD. A utility contracting crew was changing a pole after a storm. When they augered the hole they hit a gas main. One of the trucks ran away and the engine blew, igniting the gas leak. Luckily nobody was hurt, but they did loose a couple trucks and had to change their pants I'm sure.

 

[91W350]

I clean out my CUCV pre filter foams with solvent, when changing the air filter. My son offered to help me and did not blow it as dry as do, not wanting to knock his work, I installed it a little wet... I had changed the oil and fuel filters as well. Anyway, when I fired up the truck, it took off. It raced for a few seconds, even though I turned the switch off, shutting down the fuel supply. It took a few seconds to dawn on me what we.... I had done. I did not even think about it running on solvent, will not be making that mistake again!! Glen

 

[WillWagner]

Yup, it happens quite a bit, especially on newer engines. The turbos are no longer just charging cylinders, they are being tasked with pressurizing exhaust systems, (EGR), slowing engine rotation, (VGT and swing vane), as well as normal turbocharging duties. Most fleets have guys that change bulbs. FedEx, UPS, USF/Yellow come to mind. When a turbo fails, these guys just slam another turbo on the unit, nevermind the aftermath of the failed turbo. About 4 times a month I see trucks from the above mentioned towed in with holes in blocks from run aways due to the "technitions" just slamming another turbo on the unit and NOT claening the CAC of the oil pumped into it from the other turbo.

 

[dittle]

My uncle was a M109 SP Howitzer mechanic during Desert Storm. He told me of a runaway from one of these units during a ground hop test. He said that whenever they did engine work they would ground hop them before re-installation which is a good idea. Well this engine did a runaway and a Sgt. happened to be walking around with a set of TMs in hand. The Sgt. ran over with the TMs to cover the turbo and snuff the engine out. Well the turbo just sucked the TMs right out of his hand and through the engine....time for a new engine.

 

[zout]

NDT - your story reminds me of unloading at the TOTAL plant back up in Mich after picking up at the "Dome" in Sarnia Canada through Port Huron.
These are 120,000 Bottles of IsoButane - or Butane or Propane - depending on what the order was.
Back at the Total plant in Alma Mich while unloading another driver was finishing pumping off and got distracted by another person who was talking to him (you NEVER allow yourself to get distracted till you are free and clear of pumping off and everything stored away).

He forgot to unhook his pump off line into the main line and pulled away with the valves still "open" on his bottle and on the main line with the line attached.
There is no place to run fast enough and close enough to have cleared an explosion - the driver left his tractor running as well - the plume of vapor was making the tractor jump litterally OFF the ground and sucking in fumes. One of the Total personnel at the plant got the main line valve shut and then his tractor pump line. Tractor is still clearing the ground sucking in vapors and running off them. The driver was running away from the area. But the Total personnel got the tractor shut down (we were also running to the tractor but he got there first)
The driver lost his license to access these plants and the company he was driving for lost access to the plants for 6 months while all their drivers were sent back to training.
The tractor running when it first started sucking in fumes - should of blown.

 

[rickf]

I had an old White OTR tractor run away on me. It was a yard truck at that point and it was receiving NO maintenance at all. I would bring a trailer into the yard and drop it and then use this yard truck to move the trailer since it was a short day cab and easier to move around the yard. As I was dropping the trailer from this yarder it just started to wind up. Not instant but just kept getting faster and faster. I had plenty of time to realize what was happening so I got the air cleaner off and slapped a piece of plywood on it. It shut down in a fog of oil and diesel smoke. We kept a piece of plwood in every truck for just this use. That was a 671 Deetroit and all they did was pull the turbo off of another derelict truck and put it on, good to go.