Losing my mind. L84 swap no start.

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07-28-2025
Chasechad22

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Losing my mind. L84 swap no start.

I have L84/8l90 E90 setup that I have been troubleshooting for a month now. Regulated fuel system set at 72psi but only getting 150psi at fuel rails and sometimes less. Vats and starter diagnostics disabled. I have spark and motor will run on ether. No current DTC present. Scanner reads RPMS and cam counts. Not seeing injector pulse and desired fuel pressure is reading 0. I also noticed when the motor was running on ether it was still showing 0 oil pressure. I have included logs. Log shows it running on ether at 4600. Desperately searching for help. Thanks in advance.
Attachment 163188
07-29-2025
Rtex15

Exact same issue im having, been on and off this truck, tried different ecm, different yr write entire, swap safety neutral switch, traced down wiering it has to be something in the ecm I need to change just don't know what
07-29-2025
Chasechad22

Quote:

Originally Posted by Rtex15

Exact same issue im having, been on and off this truck, tried different ecm, different yr write entire, swap safety neutral switch, traced down wiering it has to be something in the ecm I need to change just don't know what

Glad to know I am not alone HA. I am on my second computer as well. Keep me posted if you learn anything and I will do the same!
07-29-2025
edcmat-l1

Almost always when a "swap" vehicle won't run it's due to wiring, installation, etc. and NOT the PCM and/or tuning. As long as the VATS has been disabled correctly, it should fire and run.
07-29-2025
Chasechad22

Quote:

Originally Posted by edcmat-l1

Almost always when a "swap" vehicle won't run it's due to wiring, installation, etc. and NOT the PCM and/or tuning. As long as the VATS has been disabled correctly, it should fire and run.

Thanks! It appears I am getting nothing from the HPFP so I will start there I guess. Everything else on the harness has checked out so far.