Hey all, i have a 2014 L83 Sierra, Installed a Whipple, Katech 103MM, TB and a LT4 HPFP and Injectors. The truck is currently a paperweight. Hunts for Idle, and goes into Reduced Power mode about 30 sec to a minute after startup.
I have the following codes
0x7E8: P0068 - MAP / MAF - Throttle Position Correlation (SES, Pending, Current, History)
0x7E8: P0089 - Fuel Pressure Regulator Performance (SES, Pending, Current, Old, History)
0x7E8: P0101 - Mass or Volume Air Flow A Circuit Range/Performance (Pending)
0x7E8: P0106 - Manifold Absolute Pressure/BARO Sensor Range/Performance (Pending)
0x7E8: P0420 - Catalyst System Efficiency Below Threshold (Bank 1) (Permanent)
0x7E8: P0430 - Catalyst System Efficiency Below Threshold (Bank 2) (Permanent)
0x7E8: P16A1 - Sensor Communication Circuit High Voltage (Permanent)
0x7E8: P2099 - Post Catalyst Fuel Trim System High Limit Bank 2 (Permanent)
0x7E8: P228C - Fuel Pressure Regulator Control Performance - Low Pressure (SES, Pending, Current, Old, History)
I attempted drive it around the block and wow that went terrible. With the codes posted above I looked at Rail Pressure and saw it was way low, so all the codes pointed to a defective HPFP, So I removed the LT4 HPFP and warranted out the AC Delco pump. I just got a new Ac Delco LT4 HPFP, AND THE TRUCK STILL HAS LOW RAIL PRESSURE.
Am i just missing something in the tune? I compared the LT4 HPFP to the L83 HPFP and they have the same piston depth and spring height.
Im pulling my hair out so any help is appreciated
as read 103TB and LT4 with changes.hpt
first drive.hpl