Decided not to hook it up to a gauge. There's no reason for it. It is obvious the pump had quit. With the low pressure showing to be dropping to 1.3 bar as well as the high pressure dropping to 30 bar...there's just no reason to believe the low pressure sensor may have failed. It is definitely a loss of delivery from the Quantum. Also, I don't think it can be a failed filter regulator because it holds the low target until I floor it and load is applied. Then, after I let off the throttle the low pressure actual jumps to 7.5 bar. And this says the regulator isn't always feeding the fuel back to the tank. So, going to wait on the replacement Quantum and install it when it arrives.
If this next one fails quickly, or at at any point really, I am just going to get a new oem pump and remove the PM3. My GIAC K04 H.O. tune works without a LPFP upgrade or the PM3. I only added the pump upgrade and PM3 because of the time I ran the DM tune. Everything was perfect with the original GIAC tune with the oem pump prior to trying the DM tune.
DM tune was a bust in every way. He tuned it to run open-looped; high rail pressure(142.50 bar), high low pressure(5.5 bar), high boost(26 - 30 psi), and it never beat the 1/4m et of the giac tune...never even got within 0.5s. So, it cost me $700 for the DM tune, $600 for a USP High Flow LPFP($100 more than the TTRS), $500± for the PM3, $150 for Techtonics to retune it to stock and then to reload the GIAC when I was done with DM's tune, plus the 3 bar MAP sensor. In addition, and before all the fuel related bits mentioned ↑ ...he first requested I replace the low and high pressure sensors when the pressures weren't reaching what he wanted to see. So about a $2k+ loss. Then there was the rebuild at 120k miles due to the piston ring that got stuck in the #4 piston. So, another $3k for the rebuild at just 120k miles. Total loss for trying the Driver Motorsport K04+ tune was $5k+. This is what I imagine it is like when one seeks to squeeze out every bit of HP from a big turbo build with custom tuning. I just want the car to run really well now.