buddy's LMM is hurt

[Yngdmax92]

Still isn't low enough to warrant an issue that bad is it? I've seen engines have 350 across the board and not have them startability problems. I think you need to dig deeper

 

[N2BRK]

the low numbers don't bother me if they were consistently low across the board... it would just be "tired" perhaps. But those low numbers in the area of concern are troubling.

 

[Ne-max]

That oil on glow plug concerns me the most. I'm gonna guess he has some cracked pistons.

 

[2004LB7]

Have you ohmed any of the pigtails yet?

 

[TheBac]

That oil on glow plug concerns me the most. I'm gonna guess he has some cracked pistons.

I was thinking the same thing.

 

[N2BRK]

He left to get a borescope and I pulled the injector going to look in 5 and then ohm our electrical

 

[N2BRK]

Borescope too big to get in. Lol. The tiny one wasn’t at work to borrow. Can’t see shit with this one. Ohming out pigtails next

 

[N2BRK]

Delayed now. GM login isn’t working to look up the service manual and the tech with the actual account is hunting deer. Lol. So we have to wait. I did a google search and didn’t come up with the wiring diagram and specs.

 

[MarkBroviak]

This is what happened on my truck push rod was bent to the point the valves were hung open all the time


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The valves hit the pistons and that is what bent the pushrod on it. Not sure what you were doing when it happened but a lot of the times the exhaust valve will hang in the guide and that will bend the pushrod like that. Backfires will also this to happen too.

 

[MarkBroviak]

Hey Wally, looking the info you posted along with being in the truck when the nozzle came loose like it did I bet it did something in the cylinder if you move the injector and the issue doesn't follow it. It is odd that 5&6 are both down on compression like that though! I hope it is something stupid and an easy fix for you guys cause it was great until the nozzle nut came loose!:hug:

 

[N2BRK]

crazy. Especially when they were put together with a fancy assed snap on torque wrench. I guess your "gootentight" is more accurate, lol.

 

[N2BRK]

I’m thinking since now we know 5 and 6 are the only ones low on cr, and they share a journal... ugh

 

[gmduramax]

I’m thinking since now we know 5 and 6 are the only ones low on cr, and they share a journal... ugh

Not good

 

[2004LB7]

Delayed now. GM login isn’t working to look up the service manual and the tech with the actual account is hunting deer. Lol. So we have to wait. I did a google search and didn’t come up with the wiring diagram and specs.

Have you tried GM Upfitter?

https://www.gmupfitter.com/files/media/photo/477/2009_LD_ElectricalPickupsChassisCabs_100813.pdf

At least it has the diagrams. If nothing else, check for any to be different then the rest. You could check for continuity to ground on each of the pigtails, then pull the connection off the ecm and test again.

 

[N2BRK]

For shits and goggles I went negative side of pigtails to negative terminal of batt. All same resistance on every piggy

 

[2004LB7]

Try it again but reverse the test leads. And if your meter has it, try diode setting

 

[N2BRK]

So just thinking aloud here... the injector tips were all torqued to spec, yet after the failure the tip on #5 was loose. We tightened and new Orings and observed it still leaked in the cylinder and out the top. Engine now damaged. My thought is the injector failed somewhere in the body. That crack pushed on the nozzle (there was some visible damage in the thread above the nozzle) and caused it to loosen a little. The crack allowed massive fuel to snuff out the flame and hydro lock the engine. The engine did shut down on the drive - likely hydro locked. The failed 5 injector causing the hydro lock damaged the rod and possibly more and hurt the sistered #6.

Plausible?

Our plan is to pull the engine and tear in for sure.

 

[NC-smokinlmm]

Fuel cuts are violent and easily break shit, I'd bet when the injector took a dump it freaked out the ecu and it cut fuel. That in turn probally led to physical damage, broken crank, bent rod or maybe the piston or rod connection. I've seen fuel cuts on outboards break the cam shaft as well...

 

[zakkb787]

The valves hit the pistons and that is what bent the pushrod on it. Not sure what you were doing when it happened but a lot of the times the exhaust valve will hang in the guide and that will bend the pushrod like that. Backfires will also this to happen too.

This happened after putting the motor back together. All the valves were lashed to spec and everything was sealed up. I guess I had done something wrong since it was my first time into the engine. First start up I knew something was wrong. Had to tear it back down after a compression test to find it. Still confused on how it happened. Sorry don’t want to derail

 

[2004LB7]

How's the blow by on the engine (when it was running badly)? Shouldn't that be an indication for a cracked piston