Runaways

[sparks57]

I'm starting to get concerned, I went to go turn the fuel screw in another 1/4 of a turn (seeing how far the stock clutch will go... 38psi so far!)... and when my truck is out of gear, when I rev it up, it kinda floats down real slow, instead of dropping down like it did at 1 1/2 turns.



I dropped it back to 2 turns now, and it's dropping down faster.



Is this something to be concerned about? I got a lever-clamp for my inlet hose so I can pop it off in a hurry and did some drills with my g/f so she knows what to do...



Also, can someone please explain to me what causes and what happens during a runaway? I know that truck can start sucking oil from the turbo, and that's when the crap really hits the fan...



But what causes it and what is happening while the truck is running away???

 

[MMiller]

One way a diesel can run away is like you said, getting oil from the turbo in to the intake. Not much you can do but stick it in a high gear, ride the brakes, shut the key off and hope for the best. If you EVER have a turbo seal fail and oil gets in the intake side, pull the ATAAC (air to air aftercooler). I have seen trucks that get the turbo switched, but there is still oil in the ATAAC and then the engine runs away on the oil. So if the turbo fails make sure there ain't no oil in the ATAAC.



The other thing that can happen is if the governor fails in some way and the flyweights can't push the governor to the off position. Whenever we work on governors on engines, before startup, I have the air cleaner off, and somthing to choke off the air. Occasionally a guy get the governor together and the flyweights anen't hooked to the governor assemble. What happens is the pump goes to full fuel and there is nothing to tell the pump what rpms its running. See the spring is trying to make the speed increase and the weights are trying to make speed decrease. They find a happy medium in a correct working system. If the flyweights are unhooked the spring says more fuel, and there is nothing saying SLOW DOWN.



The last way is when ether is involved. In the winter time starting diesels can be aided with a shot of ether. I use is as little as possible. If the engine is turning over slowly, and you shoot ether in to the air cleaner, it may not get sucked in the engine. It can and has pooled in the ATAAC. Then when you jump the engine, or put new batterys in it and the engine starts it will suck up all the ether and the engine will run away. Whenever I use ether on a diesel with a ATAAC, I unhook the air piping right at the intake and shoot the ether in there, WHEN THE ENGINE IS BEING CRANKED. When the engine starts let it run a few minutes and then put the piping back on. Never use ether on your cummins unless the inlet heater is dissabled. Never use ether on a glow plug engine. I had a 6. 5 pop back throught the intake because of the glow plugs heating up and igniting some residual ether(it was cold, needed to get it running).



There are three ways i have witnissed. All bad news. Diesels don't like lots of rpm!



Sorry for being longwinded, I have a hard time giving short answers.



Michael

 

[MMiller]

Oh, and what is happening. The engine is running on some type of fuel sorce that is not being regulated, ie oil, fuel, ether. Another instance is if a diesel is running and some propane gets away, line leaks or something, and the engine gets a wiff of it it will run away.



All thats happening is the engine is getting lots of fuel, and keeps revving until the pushrods fall out, rocker arms fail, the valves hit the pistons and compression drops off, or in bad cases rods start ventilating the block from the inside out. Different diesels have different weaknesses. If the valve train holds together long enough, then the rods start comming apart!! Then you have a real MESS.

 

[Jim Fulmer]

I guess you have never been to PDR were they have the run away board for the 1st gens.



Jim

 

[sparks57]

Thanks for all the valuable info. My truck was kinda running away a while back after I did a governer spring install and the governer went haywire.



Fulmer: are you saying that first gens are at a higher risk of running away?



I have replaced the clamp around the inlet of the turbo to one with a quick release lever so I can get it off in a hurry, and I have a small piece of plywood behind my seat. I don't want to take a chance.



So is my truck nearing run-away condition? So a truck will ONLY run away if there is a governer problem or the turbo is leaking oil into the intake?

 

[dpuckett]

Loan the kid a pump to keep him from walking, and look what he does. Cerberusiam, I hope to heck it was a junk pump; it may well be when he gets back. Seriously, though, back it off, and see what you get. I'd think you should get more than 38psi, with your big honking injectors, since I can hit 35 pulling a 5K load with my milder impellar, bigger exh housing, and stock flow EDMs. But then, I have about come to the conclusion I have governor issues, (no, not the moron in the state capitol, though that IS another story), so that could be part of my overboosting.



It sounds like you were close to running away there for a bit; it would be wise to lave the full power where it is, and mess with the AFC. ARe you running your Old Smoky pin in the loaner, or does it have the stock pin? It may need some modifications if it is a stocker. Hey, since you're abusing your pickup so, get me some numbers so I can buy a rebuild kit for the turbo prior to installing it in my SANELY driven old beater. Though next week, it may get a workout... ... . hay season is here, and a neighbor has a 35ft GN trailer... ... Oo.



Daniel

 

[sparks57]

Basically, is something wrong that my truck is floating down instead of dropping quickly in RPM's in neutral?

 

[dpuckett]

Yes, as I understand it from the Scripture atop the Forum, the governor springs arent quite sftiff enough to pull the flyweights back after a certain point. (?)

 

[sparks57]

Hey now, I'm not any harder on my truck than any other wanna-be hotrod first genner around here.



I drive like a grandpa until I make a mod and test it, or when I come across a good race! I ussualy don't see more than 10psi.



I'm sure I can make more than 35psi, but I'm not going to push this loaner pump, especially when it's not the correct one.



I've backed the pump off to where it no longer floats.



Like I said, I would have had a new pump two weeks ago but I work whenever PDR is open, but I'm looking at my options.



I'm currently wondering if I should get a new pump or rebuilt, performance or not. I have my own way of doing the DV's, I have my own fuel pin, and my own governer spring, so I don't think a performance pump would be worth the money. I think a new pump would be a good idea.



Hey PB: are you available tomorrow (saturday)? I really need to get a new pump!

 

[phillips5]

Nothing is wrong all the ve's that I have turned the screw in too far did the same thing. On the first one the truck was idling out side and I herd it coing faster and faster probly 3500 by the time I hit the key ( what a rush). Something in the governer just about goes over center when the screw goes in to far. The screw is kind of like a falcrom point not realy a dead stop for the metering sleve (I think these pumps are sleve metering). So back the screw out til it just starts idling right.

 

[1stgen4evr]

the governor springs arent quite sftiff enough to pull the flyweights back after a ce

Once engine speed and consequently flyweight inertia exceeds the ability of the governor spring/s to return control to a low setting, there is nothing to stop it except some method of blocking fuel or air. And the sooner the better.



If you are doing anything that is on the edge, be ready. I know for a fact that a baseball cap is not enough to stop the bigger cummins engines. The blocker board is a good idea. Runaway is such a problem on the two cycle detroits that the blower has a stop/kill door built into it.



When they get to the point of knocking holes in the block, it is best to duck for cover. They will get really really tight before they turn loose however.



1stgen4evr

James

 

[MMiller]

You otta do what the truck pullers do, I have seen it on sled pulling semis. The air intake tube is just some tube, then put a rain cap on it. Put a spring pin to hold the rain cap open. Attatch a cable to the pin and run it in the cab. Now if the engine runs away, pull the cable, which removes the pin and the rain cap slams shut and stops the air!! TADA! On more engine running!!



Or you could set the pump right so it don't run away!



Michael

 

[sparks57]

So then these guys running 450+ hp in a first gen have modified the governer?



Thanks for all the tips and insight... this should prove most usefull.



Looks like this pump can only handle 2 turns. But that's good enough for now! Now if I could just find time to call Piers...



Somebody needs to tell Piers to open up the phone lines of Saturdays!

 

[roadhawg]

You don't modify the govenor, just the lever about 1/8th of an inch



only 450hp?







happy bombing

 

[BushWakr - RIP]

Hey now,... . don't start that... those guys work from near dawn to well after dinner every night... literally... well, ok, pretty near. .



CB, you're just one of these guys who's actually gotta see something to believe it... .

OH, don't use your hand over the air inlet to the turbo... . or you'll be called stubby or 3 finger'd Dave... . sorry dAvE... .



pb... .

 

[bgilbert]

So then these guys running 450+ hp in a first gen have modified the governer?

No they've installed a p7100 pump right Bob? -and near voided their 1st gen pass...

 

[Marty1]

I actually heard a rumor that it's OK to change the pump on a First Gen truck. It's injectors that are the problem... anyone running altered injectors will be black-balled from the First Gen Forum I'm told.