Arduino Mega 2560

I am using Mission Planner 1.3.36 build number 1.1.5911.13630, and Arducopter APM v2.8 everything works as advertised. So I thought i would see if i could get an Arduino MEGA 2560 with a MPU-9250 to function in a similar fashion. when I install firmware it seems to install fine but when I go to the next step of the initial set up things start going wrong. when connecting to MAVLINK the operation times out and I get the message that no heartbeat packets were received.

Any ideas as to why?

Is there something else I need to connect?

I am connecting the MPU-9250 to the Mega 2560 gnd to gnd, vcc to 3.3V, scl to scl and sda to sda. Mission planner shows i am connected on Comm 6 to arduino Mega 2560 and the baud rate is 115200

thank you