New 6.7 long block - No compression

Joel Browning · September 11, 2015

I had something very unique happen with a new 6.7 Long block. Tried to start it for the first time and let it crank for a long time. While it's cranking it's very uneven and tried to start several times. No codes popped up. Checked to make sure I was getting fuel and my pressure was good. I ran a relative compression test and found cylinder 5=16%, 6=10%, 7=16%, 8=18%. I did a manual compression test and #8 was the lowest at 170psi. Before removing the valve cover and disabling the engine completely I added oil into the cylinders through the glow plug holes and cranked. I ran another relative compression test and now they are all 0%. After running the compression test the truck starts and runs good. It's interesting that only one bank that had no compression.