Haidl and another former assistant sheriff, George Jaramillo are scheduled for sentencing on September 14.
U.S. District Judge Andrew Guilford ruled Tuesday that Haidl could not show he needed the additional time.
Carona was convicted of witness tampering based on a wire that Haidl wore during a meeting between the two men in August 2007.
Carona was sentenced to 5 1/2 years in prison. He is expected to begin serving his sentence July 24.