Pwm with arduino and l293d

Hi I have just finished my first robot build uploaded sketch and discovered one motor running faster than the other i am trying to slow down faster one with pwm on enable pin  but i just cannot get it 2 work with pwm pin 10 on arduino connected 2 enable pin motor just wont turn at all if i remove pwm pin motor turns please please help my sketch compiles and runs no probs even if i remove power to both enable pins on l293d so im guessing it a wiring problem

You have the pin

set as an output, right?

Otherwise, you could include a quality pic showing your connections and maybe your sketch for good measure.

l293d

Hi thank you for your reply, I have defined enable pin for right motor and set it as output,pin is connected to arduino pwm pin 10.I am using seperate 9v supply for my motors on pin 8 of the l293Dwith ground going to arduino (common ground).My sketch runs fine robot responds as it should in every way except it turns in arc as right motor has slightly higher R.P.M If i remove power from right and left enable pin the motors still run but when i reconnect pwm pin on enable pin it stops the motor and it doesent move.