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Hey everyone, I have been a long time lurker on many forums and I have decided to post some questions because I am at the point where I believe I need guidance on next steps and want to make the right decision. The car I am working on is a 78 280z California Car. It is not my car, it is my parents car that I bought them as a gift 10 years ago. It has been a long time since I have driven the car so I don’t recall its characteristics but it always had a presence of fuel smell in the exhaust. The car was parked because the fuel smell and rough driving started getting worse. The car then sat for a year and a half and now its time to get it back up and running. All the items addressed have been done within the past four months. Disclaimer: There is a lot of information here and if I am unclear on anything please let me know. I am trying to get some conversations going and wanted to put my best foot forward. Symptoms Bogging/hesitation/stuttering under any load to the point where the car can’t be driven, can’t emphasize this enough. Car idles immaculately Backfiring through the AFM Fuel smell through exhaust Current State Timing: 10° BTDC Idle: 800 RPM Aftermarket exhaust header and muffler EGR deleted Air regulator removed Coldstart injector still on rail but disconnected electronically Thermotime switch disconnected electronically Items that have been addressed Spark: New Plugs (NGK at .039in gap) New Wires (NGK) New Coil (MSD Blaster) Rebuilt ZX distributor (RockAuto) Vacuum advance confirmed working New Cap New Rotor Fuel: New fuel injector connectors Injectors reconditioned from Fuel Injection Services (confirmed working) New Walbro 255 fuel pump Tank removed and checked for rust Fuel hard lines cleared with compressed air New fuel filters (pre and post pump) Inline gauge added between filter and rail Air: AFM has been calibrated per atlanticZcar site rebuild guide Bench tested for smooth sweep (open to close) Calibrated spring force with water weights New PCV valve Engine: Valves adjusted to: Intake: .008in Exhaust: .010in TDC mark confirmed correct on main pulley Distributer shaft confirmed 11:25 position Leakdown test performed Compression test performed Electrical: New coolant sensor New coolant sensor connector New TPS wiring connector Contacts cleaned with deoxit ECU Harness tested in car to EFI Bible specifications Results Leak down and compression test performed cold because the vehicle was not running at the time. The AFM sweep was performed using a 9VDC battery and an arduino. I did two sweeps of the door by hand as smooth and slow as possible. The third sweep I intentionally pulsed the door through the sweep motion by hand to see if something else would happen. I did not see any signs of a bad circuit. The FSM provides a table relating resistance to temperature for the air temperature sensor and coolant temperature sensor. I generated a chart using this data in both °C(Blue) and °F(Orange). The trend is not linear so a polynomial trend(Thin Orange) was generated so I could plug in a measured value to determine a temperature. The table also provides acceptable ranges within specific temperatures so I added error bars to show this acceptable range. The test environment(Green and Yellow circle) was what the temperature should be and the measured (pink) value was within the error bar at that condition. I went through the circuit testing per the FSM and found nothing alarming. Observations Advancing the timing beyond the timing marks helps but doesn’t resolve the overall issue. Timing at 10° makes the car impossible to drive. Timing at 25°-30° makes it bearable but only above 30% throttle. Future State I have worked through what I believe to be the cheapest items to inspect and now believe it is time to find a new AFM and ECU set. Everything appears to be correct and by the book. Should I try to find a 78 280z ECU/AFM for a CA car, or should I find one for any 280z car (non CA). I have toyed with going standalone because at this point I am tired of poking around in the dark trying to troubleshoot this car. I need some assistance from people who have experience with the FI systems on these cars and I don't know anyone locally to reach out to. If I am unclear on something, please ask and I will provide.