Engine took off, now it won't start.

Max Attitude

Max Attitude

11SIX
Mar 7, 2012
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Caledonia, MI
I have a friend who bought a 2014 LML that was previously rolled. He has been fixing it up. Today he had it running and he was trying to see how quiet his new exhaust was. He said he "had been driving it around a little bit and did a burnout with it". Later he revved it up to 3k and then the engine took off screaming. He turned it off with the key and now it won't start. In the process it blew anti-freeze all over the place. I have not been there to look at it myself. It cranks over and sounds like it almost fired over the phone. Any ideas? It had some smoke coming out of the exhaust earlier (probably from oil everywhere from the rollover). There is oil in the exhaust piping… I think he noted that before this incident. Thought maybe a runaway but it shut off with the key. Stuck injector? Any help appreciated.
 
R

RickDLance

Active member
Feb 14, 2007
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Sure sounds like it sucked in a bunch of oil and ran away with itself. Might have dinged some valves. I have one here that windowed the block.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
dont those have a butterfly valve on them on teh cold side intercooler pipe? if so, when he hit the key, that probably closed the valve and was enough to snuff out the air/oil entering the motor.
 
andy-stevenson

andy-stevenson

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Jul 7, 2013
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Just seems a little weird that he had it out and running and it was fine? Did he just have it in park and was revving it up or driving around?
 
chevyburnout1

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
Chevy1925 said:
dont those have a butterfly valve on them on teh cold side intercooler pipe? if so, when he hit the key, that probably closed the valve and was enough to snuff out the air/oil entering the motor.
Click to expand...

I know the Volkswagen's have this programmed on their TDI's. The valve is commanded shut for a few seconds after shut off. Saved my ass on a runaway for sure! Not sure if the Duramax's are programmed to do that though.
 
770JOHNNYW

770JOHNNYW

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Sep 16, 2009
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I had one do that it was an lb7 though the fuel pressure relief valve had stuck open I know what LMM doesn't have that but I would check the valve at the back of the driver side rail
 
770JOHNNYW

770JOHNNYW

New member
Sep 16, 2009
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Gainesville ,Ga
Actually do the later model's have the relief valve in the valley? I may have told u wrong but I had the exact situation with an lb7 running away it would start up and run all day with a little ether but shut it down and it would not start for anything. The fuel must have pushed the valve further than ever before. Stuck and never came back.
 
Dozerboy

Dozerboy

Well-known member
Jun 23, 2009
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TX of course
It would if the butter fly valve closes enough, but I don't think it does due to other discussions I've read. It would also depend where its pulling "fuel" from and how much.

We had an excavator run away, but once it ran out of oil to burn it was fine. New turbo and it was back to work.
 
K

krazykevin58

New member
Jul 4, 2015
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I had an lb7 over rev (a drunk on the end of an ether can), bent every exhaust push rod if I remember correctly, and broke several of the "buttons" on the rockers. Replaced all bent/broke parts with used, ran great for about 5,000 miles till it dropped a valve, destroyed the engine. So if this ends up being the case (bent pushrods), check your valves/retainers very closely while you're in there. I have to assume my valve dropping was closely related to the over rev somehow
 
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