Prolonged crank time with tip start

[bigb206]

Hi Everyone!

 

I have 2016 Tahoe PPV 121k with a prolonged cold start utilizing the tip start function. I'm new to direct injection, I read the direct injection does take longer to start than port injection, but this seems excessive approx 3 secs. I don't experience this with letting the fuel system to pressurize and then start it. I checked GDS2 and noticed a pressure drop on both the low pump and high pressure rails after the engine is off. 

 

Does anyone know if direct injection is suppose to keep pressure in the rails for an extended period of time? If so what is the threshold? 

 

I also noticed that the actual pressure is higher than the desired, initially then levels off..is this concerning? 

 

Any help is appreciated!