L293D Motorshield Perhaps not supplying enough power to motors?

Other Hardware Robotics
1

I am building an obstacle avoiding 2WD Car, and my motor shield seems to not want to comply in the sense that it may not be powering the motors enough. However, when I give the motors a direct 5V source from the pins on the shield, it is sufficient for powering them, with a sufficient amount of speed.
The build is based on the following tutorial: Obstacle Avoiding Bot Tutorial

The motor shield I used: Motor Shield Link

The Chassis I used: 2WD Chassis

Also I am powering the Arduino and motor shield through a power bank: Power Bank Link

I am looking for some guidance on what I may be missing, or perhaps is faulty. All feedback and help is appreciated. Thanks.

2

The L293D is very inefficient and is likely to be dropping 2-3V so you're probably getting no more than 3V across the motors. You really need to be powering it with at least 6V, preferably more.

steve

3

The L293D is ancient and weak. Use a modern motor driver, like these from Pololu.