LML Lgh in a lml. Cranks but won't start

kvw4x4

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Oct 7, 2015
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To make a short story long. We bought a 2014 duramax with blown motor, with egr def delete. We bought a motor I was told it was a lml. Ended up being a lgh, out of a cab chassis 2013, everything matched up other then one egr plug. But being as egr is deleted it shouldn't be a huge deal, the truck cranks but won't fire up. Any suggestions ideas things to check. Thanks
 

kvw4x4

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Oct 7, 2015
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Watch rail pressure while cranking. Also watch for crank and cam position signal while cranking.
I found a edge cts in my personal truck and ran it on this lml-lgh to check fuel rail pressure. It said 0.0 the whole time while cranking. I took a screen shot while cranking. Notice rpms
 

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kvw4x4

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Oct 7, 2015
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While cranking it over last night we cracked a couple injectors and seems to be pushing fuel out.
 

ikeG

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If the fuel system was completely drained it will take quite some time cranking to start. Check all supply lines. Make sure fuel filter lines aren't crossed. Just going to have to go over everything associated with the fuel system

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kvw4x4

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Oct 7, 2015
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Little update. I was able to get 0.1 on fuel rail pressure. When we cracked injector lines and cranked engine over we had plenty of pressure. Could truck have fried ecm? Or would it not crank at all. I'm lost.
 

kiwilml

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Nov 4, 2015
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X2 but I would try using a air hose an blow back pressure.. They have a check valve that's supposed to hold back pressure on the injectors.. And if that has seeped off then they won't open.. Happened on my brothers truck one time and applied a little back pressure with air and she fired right up..
 

kvw4x4

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Oct 7, 2015
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X2 but I would try using a air hose an blow back pressure.. They have a check valve that's supposed to hold back pressure on the injectors.. And if that has seeped off then they won't open.. Happened on my brothers truck one time and applied a little back pressure with air and she fired right up..



We have tried both clamping down return and also putting air Into system through fuel return line, Starting to lose my hair
 

454ss70

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Mar 8, 2017
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p268c injector 1 cal incorrect

p0675 number 5 glow plug issue

Would go back and check all your electrical connections to make sure you didn't miss one.
 
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FC5452

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Mar 17, 2013
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Eastern PA
Hi there, the incorrect cal would not cause a no start condition, but bad miss will occur, glo plug is self explanatory, same as its predecessors, still will not cause a no start.
You need at least 2000 psi on crank and 45 psi return line reassure to fire the piezo.

First you need to find out why your not building rail pressure,

You can check the driver side fuel rail relief regulator, by removing the rubber hose and verify it's not leaking by on crank, regulator 2 as it is called is located on the front driver side fuel rail.
If nothing is bleeding off check regulator 1 on the cp4 for metal shavings on the screen.
If you are indeed building pressure, then clamp the injector return lines and crank til she fires off, then remove clamps.

The cal incorrect could be a bad ecm, had one happen couple weeks ago.


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kvw4x4

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Oct 7, 2015
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welp don't buy duramax parts from the guy on sacremento craigslist, the motor with 36k that I bought from him which was supposed to be a lml ended up being a lgh, that had a bad cp4 and also a fried computer, a lot of work we are ready to drop the motor in, after a cp3 conversion, new injectors, and cleaning the entire fuel system, new computer and new tunes, I really hope this truck is ready to run