Thanks. Can you share a datalog of your latest setup? It sounds like everything is working well on your car and I’d like to compare how your fuel pressures compare to mine with BPM4 Stage 2 LPFP, but with old original 2008 sensors. Thanks.
Think about your graph here...
1. If you had a bad LPFP - which you know is not the case because you installed a new stage 2 unit, then it would not hold pressure. Here it makes pressure, then goes away, then repeats. The graph shows a voltage sending that is trying to match data from a faulty sensor imo. If you give the controller false data, it will send the corresponding voltage. Since the controller is new, the stage 2 is new... and you are getting these spikes, most likely the controller is sending voltage based on sensor data.
2. If you have a bad sensor... who knows what it sends or how consistent it sends? All I know is once I changed my sensors, everything was ultra smooth and fuel economy got higher. And I didn't even think I needed new sensors, I just replaced them as preventive maintenance.
When both sensors were replaced and I still got spikes, it was before the BPM4 controller was installed and port injection was activated via hobbs switch...which is totally inaccurate due to charge pipe gross fluctuations in pressure. Once both the sensors and the controller unit was replaced...it's been smooth as ice. Only shifting still needs to be tweaked due to increased power.
If you have a bad LPFP Sensor, it will affect the HPFP sensor on the fuel rail...a chain reaction because they are both on the same system. It could be one is good and the other is bad...but you cannot tell which one, so you should do both to eliminate doubt. If you have new stage 2, new BPM4 controller, and both sensors replaced, then you know it is most likely the HPFP. and that would be the end of the line in terms of mysteries. It is cheaper to do both sensors than go replace the HPFP and ignore the sensors...which means, you will still have the same issues because you didn't follow best practice and you chose to keep the original sensors.