Diesel RUNAWAY

SHINTON

SHINTON

Well-Known Member
Joined
Mar 17, 2005
Location
Triad area of NC
I went over to work on the Excursion some last night and my uncle had
it rolled outside and idling...I commented that it was sounding good!
He said you should of heard it a minute ago...etc.

Turns out, he pulled it out, warmed it up and started giving it some
throttle, and all of a sudden the engine started revving up on its
own! (This is called Diesel Runaway for those who have not heard of
it) Basically the engine starts feeding and revving up thru the roof
without you touching it. He turns the key off and it is STILL
RUNNING! Oh yeah..and it was putting out a oil smoke screen like
something out of James Bond! You could not literally see 10'!

He presses the brake and it finally dies...

So when I get there, I had heard of diesel runaway and called Slim to
see what causes it, etc. We basically figured out that when the Excursion was upside down it probably got oil in the intercooler, etc. We take off
the pipes and sure enough there is oil in there. Our next step will
be to remove the whole intercooler (about the size of a radiator.) and
flush it out good. (Ran it without the intercooler pipes connected and it is not blowing oil out the seal around turbo so it is ok)

Since I don't know what the heck I am doing...we ended up thinking the
tranny cooler was the intercooler, and then the SMALL little cooler
turned out to be power steering pump cooler! So this sucker has
four "radiators!" (Coolant, intercooler, tranny and steering!) What
I kept thinking was the radiator was actually the durn
intercooler..sucker is huge....

After we have the pipes off, so the turbo cannot suck oil out/runaway,
the diesel started MUCH MUCH faster/better...before it had been a REAL
hard start (cranking 15-25 seconds). Also turned out the air filter was caked/soaked in oil, removed it as well.

So not a bad night at all....Excursion starting much better...new
drivers door is wired up now, etc. For some reason the lights are not
going off inside when all the doors are closed...but another day,
another fix... :)

I am READY to drive that sucker...rrr rrrrrrrrrrrgh rrrgh.

Sam
 
Upside down?

Where'd you find this thing?
 
I was ready to call bullshit , until you threw in the "upside down" thing. Severe ring wear is usually the cause of one to run away, but with oil in the intercooler I suppose it could happen. The turbo can also put oil in the intercooler, so you may want to keep an eye on it too.
 
sam, i think you guys need to get a FSM (Factory Service Manual) if your getting that into it. The stuff you discovered after the fact should have been done before hand. Any sort of problem vehicle needs a good going through to look for issues.. Honestly id be flushing every line and hose on the truck to establish some sort of baseline, especially with long road trips in mind... You have no idea what was put into it to make it saleable.. Besides a tranny fluid flush never hurts on the 4r100. good luck
 
Hey Yag, well basically we figure nothing was done to it since the wreck, so the "diesel" fuel is probably stale (6 months old), etc etc. I am working my way thru the fluids now, already did an oil change, etc. We have not driven it on the road yet, just starting it up to move in/out of the garage so far. After we got the intercooler thing figured out I did rev it up some, SOUNDS good and the turbo whine, brings a tear to me eye I tell ya!

Yeah, the Ex was all the way upside down or durn near it, LOTS of oil still all over the air box, found a nice puddle inside it in the bottom corner last night. I was told to reach up in to where the turbine is and see if it is "loose", like the seals had gone bad or anything. But watching it for 10 minutes or so, was not "blowing" oil out near as I could tell.

We are trying to get it together enough to be driveable, etc, but before I really start using it I will have Slim (diesel mechanic) come back out and give it a GOOD checkup. We hooked it up to the scanner, NO CODES, but then again the batteries are unhooked regularly since we have some draws on them, and that probaby resets?

Oh yeah, we did get the FSM on CD off ebay!!! I have been keeping an eye out for a hard copy too, but this is the FORD CD, found lots of good info in there so far.

Sam...diesel newb...who I am kidding, everything mechanical newb..Hinton
 
SHINTON said:
LOTS of oil still all over the air box, found a nice puddle inside it in the bottom corner last night. I was told to reach up in to where the turbine is and see if it is "loose", like the seals had gone bad or anything
Click to expand...

If you have oil in the air box that means there is oil on the turbine?
Oil gets on the turbine and then dust and dirt set on it from being apart when you run it the first time will cause it to go out of balance and could cause it to wear out quick. Kind of like a tire throwing a wheel weight.
You may want to look it over real close or take it down and clean it up.
On the Dodge sites people have use the oiled air filters and "really" over oil them causing the same thing. They find themself getting a new turbo.
Jon
 
I had one run away one night at the shop I used to work at. I came in and a guy on first shift sald the truck was ready to go just needed to make sure there where no oil leaks. (he had just replaced the turbo) I cranked it up, got out and about the time I got to the other side of the truck it started gaining RPMs fast. Ran back around and cut the key off and it didn't slow down a bit. So I grabed some rags to stop the air flow. By the time I got it stoped the 4 bay shop was full of smoke. After I opened the shop door the people next door ran over to see if they needed to call the fire department.

Sam(slim)
 
I've seen an Isuzu 4H1 engine runaway due to a blown turbo seal, and I had a Duramax runaway on me last fall due to the owner dumping diesel fuel into the intake in attempt to get it running when the fuel filter became stopped up. ( don't ask, long story )

The Isuzu was able to be saved by lugging the engine down, the Dmax, a total loss. there were pix on the old board.

Sam, if any severe RPMs were reached, I would be leary of valvetrain damage, if nothing else, pull a valve cover and take a peak at the pushrods, give them a spin, make sure they are not bent at all.

The Dmax bent EVERY exhaust pushrod then dropped an exhaust valve which is what lunched the engine and turbo. It acheived well over 7500rpm before it died. A sound I never hope to hear again.

A little precuation now is worth it.
 
I would not be overly worred about oil being anywhere specific, id simply clean it all up check things out and see what develops... If it needs to be fixed it will still need to be fixed at a few 100 miles...
 
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