I'm doing my first starts on my LS swap into Toyota 86 and having an issue with fuel control.

When looking at Fuel Pump Commanded DC in the scanner it sits at a constant 0.4%. I'm using an aftermarket controller that accepts 10-90% duty cycle input in order to drive the pump.

If I use the scanner functions and in the fuel section I switch on fuel pump and enter a percentage of some sort the correct 128hz pwm signal comes out of X1 pin 50 for two seconds (and then turns off again, even though the button stays on and green). I can see the Fuel Pump commanded DC in the scanner is showing for whatever percentage I just entered at that point. However it only holds for a few second after that manual input and then drops back to 0.4% again. When I do this, I can hear the pump successfully running whenever I do those manual commands. So I'm confident the fuel pump controller is fine.

To do my first start I keep pressing the percentage up and down 1 percent around the 50% value to keep the fuel pump running and keep fuel flowing. This way I am able to start and keep it running that way at least enough to know I'm on the right path to starting/running.

However it is eluding me why manually commanding the fuel pump DC can produce the desired output, but general running/operation cannot.

I'm not using a GM FPCM. I've tried the setting for "FPCM installed" both Yes and No however it doesn't solve my problem.

Is there something obvious I'm missing in order to get a successful Fuel Pump Commanded DC out of the e38 other than just a constant 0.4%?

Cheers,
Matt