Bought an LLY Cranks no start

[03LB704.5LLY]

So bought an 04 3500 long bed crew cab LLY non running (crank no start) for 3k with new wheels and tires and rebuilt trans and tcase. The previous owner stated that the engine shutoff in the rain with no noises and when he tried to crank it back up it sounded funny (it does, seems slower) i thought oh okay I will buy this LLY and replace the starter or batts and get it going for 3k... nope I have done both and cleaned/checked connections. I can’t figure it out, I have a video but cannot find where to upload.

 

[TheBac]

Moved to LLY section of Hard Parts.

 

[gmduramax]

Rail pressure while cranking?

 

[03LB704.5LLY]

Rail pressure while cranking?

I’m not sure yet, but it does have prime. Originally I thought it was starting too slow but according to my PPE xcellerator it is between 160-180rpm and I believe that is in spec. Do you know how to upload a video here? I have a video of it cranking and it sounds totally wrong compared to my lb7.

 

[gmduramax]

I’m not sure yet, but it does have prime. Originally I thought it was starting too slow but according to my PPE xcellerator it is between 160-180rpm and I believe that is in spec. Do you know how to upload a video here? I have a video of it cranking and it sounds totally wrong compared to my lb7.

cam pin sheared, broke crank? it’s hard to say when you buy a pile of trash and have no way of diagnosing it.

 

[slowlml]

We need more info via a better scan tool to be able to help. Can upload the video to youtube then post the link here

 

[03LB704.5LLY]

10-4 thats a good idea
also I did buy a compression tester but it did not have the right adapter so I have overnighted one!

 

[03LB704.5LLY]

Here is the video

Source: https://www.youtube.com/watch?v=pI2_rleEjIU

 

[2004LB7]

sounds like it lost compression to me

 

[03LB704.5LLY]

After a failed compression test i Should pull the heads correct? Previous owner stated they were driving in heavy rain when it shut off with no noises and then when trying to crank it back up it sounded this way.

 

[2004LB7]

Do make sure it's getting air. The filter isn't completely plugged, the intake air valve is open, etc. But shutting off in the rain sounds more electrical to me

As for pulling the heads. Let's not get too far ahead. Get the numbers first and let's go from there

 

[PureHybrid]

No codes? Puffing out any smoke? Sounds pretty labored while cranking, but I've had mine still light off when I thought it was for sure dead.

I'd say it died because something is locked up, and sitting has allowed it to still turn over

 

[03LB704.5LLY]

No codes? Puffing out any smoke? Sounds pretty labored while cranking, but I've had mine still light off when I thought it was for sure dead.

I'd say it died because something is locked up, and sitting has allowed it to still turn over

When cranking over it does have some white smoke and it smells like raw fuel(very slight) I also pulled glow plugs to see if any excess fuel was being sprayed into any cylinders as I was instructed by a GM tech. I saw no excess fuel, I’m leaning more towards cam pin or something of that nature. I really appreciate all responses and all suggestions. This is the first Duramax I have experienced this with so I’m in the dark. It has 400k miles so maybe a rebuild is imminent! Either way it was a good buy and I will look into all of the smaller issues and Diagnostics before I jump the gun on it! If the Cam pin sheared would it lock the engine?

Also I have tried shaking the Crank pulley and there seems to be no play, could a crank sensor or cam sensor cause this?

*edit* So I checked the DTCs and it had like a million codes stored. The first one was 484d but I cannot find info on that code

 

[2004LB7]

Cam timing would be a good bet

I think if the ECM doesn't like what it sees on the Cam or Crank sensors it doesn't turn on the injectors. The white smoke indicates that either it is trying to start and it is not building enough compression or heat to burn it, or you have a leaking injector

 

[03LB704.5LLY]

Cam timing would be a good bet

I think if the ECM doesn't like what it sees on the Cam or Crank sensors it doesn't turn on the injectors. The white smoke indicates that either it is trying to start and it is not building enough compression or heat to burn it, or you have a leaking injector

That is great Input! I’m still going to do the compression test when the adapter comes in tomorrow. I will put the results on here. I really appreciate everyone’s insight into this because I would really love to get this thing going no matter the issue (even if it involves another engine). I would like to keep this engine as long as everything below the heads is okay but I do not want to just pull it apart before the comp test.

 

[03LB704.5LLY]

So what does it mean if you get 0 compression? I have checked all and the gauge reads zero, but I do feel air coming out of each one. I put my finger over the glow plug hole and get a push and a pull... I have no idea what the issue is, any advice?

 

[TheBac]

What are the numbers you got for each cylinder? List them out. If you did the comp test correctly, "0" means youve got a dead cylinder and some major problems.

 

[03LB704.5LLY]

What are the numbers you got for each cylinder? List them out. If you did the comp test correctly, "0" means youve got a dead cylinder and some major problems.

Every Cylinder reads Zero, I’m thinking cam shear pin... I will pull the timing cover tomorrow to verify. I changed the water pump on my Lb7 so I’m not really scared to pull the timing cover!

Also I did six revolutions per cylinder with a diesel 0-1000psi tester and correct adapter.

 

[2004LB7]

If the Cam pin sheared and is now misaligned, the valves may still be open during compression. You would not be able to build pressure that way. If so hopefully it didn't make contact with the valves or damage any pushrods

 

[03LB704.5LLY]

If the Cam pin sheared and is now misaligned, the valves may still be open during compression. You would not be able to build pressure that way

Thank you! That was my understanding after researching it but it’s good to hear it from somebody on here. Now I am starting to really understand this issue, if that’s the problem I’ll re-pin and put new heads and rods in! I bought this truck mostly to have a truck strictly for work. I am painting/putting a new bed on my Lb7 so I really don’t want it to keep taking abuse (it has really nice interior) I hate getting in it after climbing and cutting down trees all day.