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  1. U

    Help! Lbz won’t run under 1200 rpm

    Alright guys the verdict is in.... CRACKED CRANKSHAFT!!!!
  2. U

    Help! Lbz won’t run under 1200 rpm

    No news yet, but I did check the tps, and cam/crank sensors all ok. We’ll see...
  3. U

    Help! Lbz won’t run under 1200 rpm

    I’m about 90% sure it’s not injectors. All 8 were replaced with gm oem injectors right from the dealer and the truck had the issue before the new injectors but hey who knows. And yes the reluctor wheel is tight. The truck went to the dealer today... I’ll let you guys know what they find
  4. U

    Help! Lbz won’t run under 1200 rpm

    Sorry for the late reply, I’ve been out of town but I did manage to get my hands on a good known ecm and no change. I also replaced all 8 injector pigtails no change. I installed a FASS fuel pump. No change or leaks present. Also I have been over every ground a couple times I Just forgot to...
  5. U

    Help! Lbz won’t run under 1200 rpm

    Well I hooked up the O scope this morning and the cam and crank signals are good. I’ll try to get my hands on another ecm. I guess a fuel map or something could cause this? As for the injectors, I can cut each one out with my scan tool and I inspected each connector but I haven’t drag tested...
  6. U

    Help! Lbz won’t run under 1200 rpm

    Yes the air has been bled and I have ran it with clear lines in and out. No air. I’ve also unplugged the regulator. No difference. As for compression my lowest cylinder was 380 and all are within 30 psi of each other.
  7. U

    Help! Lbz won’t run under 1200 rpm

    I haven’t scoped them but my scan tool shows there is a cam and crank signal both when cranking and running. I have also inspected the reluctor wheel and verified it has a 58 tooth count. I know the earlier duramax used a 57 tooth. To clear things up the block was complete to the pan including...
  8. U

    Help! Lbz won’t run under 1200 rpm

    Haven’t tried the maf sensor. I’ll give it a shot and the coolant temp is accurate. I haven’t ran it up to operating temp yet but it does start out at ambient air temp and will rise accordingly.
  9. U

    Help! Lbz won’t run under 1200 rpm

    Seriously thanks for the help guys, Sorry I forgot to mention, the ecm is new. When I got the truck it had no ecm so I ordered one pre programmed from all computer resources. I thought maybe the new one was faulty and they sent me another. Still the same issue. I have also swapped the rail psi...
  10. U

    Help! Lbz won’t run under 1200 rpm

    Pulled that intake piece and it made no difference. Any other ideas?
  11. U

    Help! Lbz won’t run under 1200 rpm

    Doing that now. I’ll let you know how it goes
  12. U

    Help! Lbz won’t run under 1200 rpm

    Yes it runs smooth like there’s no problem at all if it’s over 1200 rpm. The injectors are new from the dealership and the egr is there and functioning. I cleaned it thoroughly before install as well.
  13. U

    Help! Lbz won’t run under 1200 rpm

    I do have a snapon Apollo scan tool which will disable injectors individually, however there is no difference with any of the cylinders cut out and I can’t run a cylinder contribution balance test because it won’t idle. Is it possible I’m chasing the wrong area? Could this be a boost issue? Or...
  14. U

    Help! Lbz won’t run under 1200 rpm

    Juddski88- do you think I could have a wiring issue with no codes? I just inspected every injector connector and as much wiring as I could. Also when I had the engine out I inspected the engine harness as best as I could. Nothing obvious was found. Thanks!
  15. U

    Help! Lbz won’t run under 1200 rpm

    Thank you for the reply, all 8 oem GM injectors. I forgot to mention the cp3 and injectors were replaced after the motor install. The problem was present before the injector and cp3 replacement and they made no difference.
  16. U

    Help! Lbz won’t run under 1200 rpm

    Thanks I wasn’t sure where to post.
  17. U

    Help! Lbz won’t run under 1200 rpm

    Hello, first time posting but I’ve been a lurker for quite some time. I’m working on an 06 lbz all stock other than cold air intake. I received this truck with the motor completely disassembled in the bed. I found out it’s an lmm block with the rest off the lbz. I assembled the motor and was...
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