I just had the same problem installing the sleeper on an old style wireless controller. I emailed the problem to KingMike and he actually called me on the phone.
Now that's good customer support.
The problem ended up being the voltage. I was using fully charged battery packs. I tried an official MS and a Nyko recharge pack. When I tested the voltage with a multimeter at the positive and ground shown in this install
I was only reading .86 volts. Mike said that was no good. I pulled out the pack and tested it, it read 2.45 volts. So Mike told me to try regular batteries. I put in 2 AA rechargable batteries and the voltage read 2.46 at the solder points and the rapid fire worked great.
I want to keep using my recharge packs. So what I did is switched the positive and negative solder points from what is shown in the install diagram to what is in the pic below. Everythings working great.