Arduino Gets Stuck!

I have a Arduino Mega 2560 connected to

L293D Motor Driver IC connected to two small size dc motors. MPU-9150 using i2c Xbee v1.1 arduino shield by seeed Li-po battery, 7.4 volts, 2200 mah. all components are tested separately, they all are working fine, the sensor readings showing data on serial monitor, the l293 drives the motors, xbee sends wireless serial data on pc, and li-po is also working fine.

i have checked the wiring alot of times. it all seems to be correct.

the problem arises when i connect all of them together, since i am using a single power source, i power the l293d with the Li-po and the Arduino also with the Li-po.

When the L293D is powered using Li-po and it starts drawing current from the battery, the serial monitor/arduino gets stuck. it doesnt show sensor readings anymore, while the dc motors start spinning. and they continue to spin, until i break connection with the battery.

without the l293d powered, the sensor readings are working fine, everything is going normal, as it should, but as soon as the l293d is connected, arduino is stuck..

i have searched alot of forums for this, found some info, perhaps something to do analog and digital ground? mpu-9150 is digital ground. so that is why it stops the arduino mega as the l293d starts drawing current. all hell breaks loose.

can anybody please help me with this? it is giving me headaches ever since!

the answer is simple. the motors has consumed a lot of power

Try to not load your mega with a big load like 2 dc motors or just use an amplifier to load them. may be, the LED in your board still lighting up, but actually, the atmega2560 didn't get any power, because atmega2560 need a little big power to power it on. And don't forget to check your li-po battery max output current.

i have used two sources.

7.4v lipo for L293D
9 volt battery for arduino

still getting the problem

attached is a detailed diagram

i have changed L293D to L298N arduino motor driver shield, it comes with a voltage regulator. which regulates the voltage coming from Li-po, to power the L298N. still arduino gets stuck, the motors keep rotating.