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View Full Version : 03 duramax 6.6.....plz help



Tex_bret
12-27-2012, 20:32
I have a 03 duramax 2500 hd...was running low on diesel but the fuel light wasn't on. When it started cutting out I pulled over and it died. I got some diesel and primed everything and was trying to get it to bust off and it wouldn't. My brother was trying to help me and sprayed starter fluid in the air intake tube and when it busted off the truck ran away with its self and hit 4200 Ron's before I could get it killed. I started priming everything and had to leave it there for a couple hours to go run errands because I'm leaving to go out if state to work next week. When I got back to my truck the fuel filter bleed screw didn't have any fuel coming out so I started all over bleeding the lines again. I still can't get the truck cranked. Any ideas of what I need to do or if something messed up when it ran away with its self but it not knocking or anything.

Kennedy
12-28-2012, 08:04
Unfortunately the ether induced "runaway" may well have taken it's toll. I hope it hasn't, but it sure sounds like it. Ether starts CAN be accomplished, but extreme care and a very minimal "wafting" of the vapor is key. Personally I wouldn't do it unless I was stranded with no help and life depended on it.

Typically what happpens with the runaway is valve to piston contact and bent pushrods. But wait it gets better. The camshaft indexing "pin" typically shears either as a precursor or as a result. This means that the cam needs to come out as well. We always "key" our cams as teh factory pin is not exceptionally secure or durable.

A typical runaway/key shear requires minimal parts. Pushrods generally and most often the heads and valves etc are OK, but we always disassemble, clean, skim cut surface, inspect, reassemble and lap the valves plus cut the cam for a key. It's a lot of labor, but on the bright side the rest of the engine typically survives without issue and you will be MUCH more educated as to the dangers of using starting fluids.

Tex_bret
12-28-2012, 21:30
Okay but how would you know if it was the push rods or cam? It's not making any knocking sounds. I have put my buddy's laptop on it (live tuning) and it shows I'm getting plenty of fuel pressure and that I'm getting plenty of fuel to each piston. We did notice that it's only getting up to like 250 RPMs and that when your turning it over I'm getting a lot of air coming back out of the air intake. I was wondering if that was normal or not? This is my first diesel to actually work on like this. All help suggestions are welcome and any advice is welcome. I won't ever use starting fluid unless its a really big emergency and my brother didn't know any better but he does now.

Tex_bret
12-28-2012, 21:56
The truck does try to bust off but never actually cranks.

rapidoxidationman
12-29-2012, 08:40
Okay but how would you know if it was the push rods or cam? It's not making any knocking sounds. I have put my buddy's laptop on it (live tuning) and it shows I'm getting plenty of fuel pressure and that I'm getting plenty of fuel to each piston. We did notice that it's only getting up to like 250 RPMs and that when your turning it over I'm getting a lot of air coming back out of the air intake. I was wondering if that was normal or not? This is my first diesel to actually work on like this. All help suggestions are welcome and any advice is welcome. I won't ever use starting fluid unless its a really big emergency and my brother didn't know any better but he does now.

If you're pumping air back out the intake it sounds like you've got an intake valve (or two or three) that isn't closing. Can you do a compression check?

For the sake of commonality of terms:
The engine cranks = the engine turns over
yes?

Kennedy
12-29-2012, 14:56
Okay but how would you know if it was the push rods or cam? It's not making any knocking sounds. I have put my buddy's laptop on it (live tuning) and it shows I'm getting plenty of fuel pressure and that I'm getting plenty of fuel to each piston. We did notice that it's only getting up to like 250 RPMs and that when your turning it over I'm getting a lot of air coming back out of the air intake. I was wondering if that was normal or not? This is my first diesel to actually work on like this. All help suggestions are welcome and any advice is welcome. I won't ever use starting fluid unless its a really big emergency and my brother didn't know any better but he does now.

Plan for both. Sounds like it is hurt. It won't make noise because the pushrods are bent and the what's left of the valvetrain may not be turning any more either.