As I work through the last stages of my 4500 -> 5400 upgrade, I note that I have a fuel flow reading of zero. Looking over the manual, I see that page 135 of the 15.1 install manual says:"AF5000 EFIS only -- Pin 5 must be jumpered to Pin 7 to power the fuel flow transducer".
I didn't do that on my 5400. Is that the reason I don't have a fuel flow reading the red cube?