[alexander7599]

2018 440i w/ 27700 miles

Installed a catless downpipe and Dorch stage 2 HPFP, let prime and tuned to stage 2 with HPFP calibrated. Everything was torqued to spec and triple checked, no leaks. Started the car with a long crank to a rough idle as expected except that it didn't go away. We replaced all 6 spark plugs to brand new NGK plugs to rule that out, misfire codes went away but still getting DTM after starting the car. Which leads me to believe it has to do with fuel pump calibration within the tune (we have tried multiple different tunes) or it has to do with the low pressure fuel pump not supplying the high pressure pump with ample fuel. However a buddy of mine with a 340i has the same setup and none of those issues.

The car runs fairly smooth above 2000 rmps but fails to get enough fuel near idle rpms.

My live data shows lambda idling around 15.7

Codes Thrown:

From BM3:
11AC02 - High-pressure fuel, plausibility, cold start: pressure too low
118401 - Mixture ECU: mixture too lean, excessive deviation
11A401 - High-pressure fuel injection upon release: too low pressure

From Carly:
11B401 - High-pressure fuel at or after the release of injection (second environmental condition set by time delay) to low pressure
11A030 - Fuel low pressure system, electric pump adaptation: adaptation value out of valid range


What I think:

catless downpipe O2 sensor
bad fuel injector
LPFP

Any and all help would be greatly appreciated. I am sort of lost at this point, short of throwing the stock pump back on and rolling with just the downpipe.

Thank you very much.

[Senhorcheeks435]

I'm driving. F36 fbo .. my problem was the hpfp fuel pump throwing the bank 1 now I got that replaced it runs like a dream with no code

[Uni-Rapide]

Originally Posted by alexander7599

2018 440i w/ 27700 miles

Installed a catless downpipe and Dorch stage 2 HPFP, let prime and tuned to stage 2 with HPFP calibrated. Everything was torqued to spec and triple checked, no leaks. Started the car with a long crank to a rough idle as expected except that it didn't go away. We replaced all 6 spark plugs to brand new NGK plugs to rule that out, misfire codes went away but still getting DTM after starting the car. Which leads me to believe it has to do with fuel pump calibration within the tune (we have tried multiple different tunes) or it has to do with the low pressure fuel pump not supplying the high pressure pump with ample fuel. However a buddy of mine with a 340i has the same setup and none of those issues.

The car runs fairly smooth above 2000 rmps but fails to get enough fuel near idle rpms.

My live data shows lambda idling around 15.7

Codes Thrown:

From BM3:
11AC02 - High-pressure fuel, plausibility, cold start: pressure too low
118401 - Mixture ECU: mixture too lean, excessive deviation
11A401 - High-pressure fuel injection upon release: too low pressure

From Carly:
11B401 - High-pressure fuel at or after the release of injection (second environmental condition set by time delay) to low pressure
11A030 - Fuel low pressure system, electric pump adaptation: adaptation value out of valid range


What I think:

catless downpipe O2 sensor
bad fuel injector
LPFP

Any and all help would be greatly appreciated. I am sort of lost at this point, short of throwing the stock pump back on and rolling with just the downpipe.

Thank you very much.

Don't know if your still have this issue but my best guess is there is something wrong with the HPFP you installed. As that is what you changed and you have HPFP related error codes.

[NickNack11]

Originally Posted by alexander7599

2018 440i w/ 27700 miles

Installed a catless downpipe and Dorch stage 2 HPFP, let prime and tuned to stage 2 with HPFP calibrated. Everything was torqued to spec and triple checked, no leaks. Started the car with a long crank to a rough idle as expected except that it didn't go away. We replaced all 6 spark plugs to brand new NGK plugs to rule that out, misfire codes went away but still getting DTM after starting the car. Which leads me to believe it has to do with fuel pump calibration within the tune (we have tried multiple different tunes) or it has to do with the low pressure fuel pump not supplying the high pressure pump with ample fuel. However a buddy of mine with a 340i has the same setup and none of those issues.

The car runs fairly smooth above 2000 rmps but fails to get enough fuel near idle rpms.

My live data shows lambda idling around 15.7

Codes Thrown:



From BM3:

11AC02 - High-pressure fuel, plausibility, cold start: pressure too low

118401 - Mixture ECU: mixture too lean, excessive deviation

11A401 - High-pressure fuel injection upon release: too low pressure



From Carly:

11B401 - High-pressure fuel at or after the release of injection (second environmental condition set by time delay) to low pressure

11A030 - Fuel low pressure system, electric pump adaptation: adaptation value out of valid range


What I think:

catless downpipe O2 sensor
bad fuel injector
LPFP

Any and all help would be greatly appreciated. I am sort of lost at this point, short of throwing the stock pump back on and rolling with just the [...]

Were you able to figure out what the issue was?