Well...something wrong. It should be cycling as fast as you can pull the trigger, RT or not.
The metal pin behind the trigger should be the RT piston sticking out like its supposed to. There should also be an air line on the outside of the gun, starting with the cyclone air line and going in the other direction.
Also you can't have the E-grip and the RT in there at the same time, so think about that before buying something
As for fixing the problem, there's either a problem with the gun itself, or the RT is tuned wrong and is effecting the trigger reset. You can adjust that pretty easy-
(This is from the RT section of the Tippmann super thread)
I installed my RT, and I can't shoot any faster.
You shouldn't be. The RT doesn't help you shoot faster in the normal sense. Unless you are holding the trigger in the sweetspot, you will be firing as normal.
I installed my RT, how do I tune it?
I installed my RT and nothings happening.
Gas up, without paint. Head outside with your RT-equipped gun and the small flathead screw driver, and do the following.
Turn the adjustment screw (This is the one on the grip side- The small one inside the air fitting) all the way in until snug. Don't crank it down too hard.
Fire a few shots. After 3-5 it should become near impossible to pull the trigger. This shows that your RT is properly installed and working. If you can still pull the trigger freely after a dozen or so shots, skip the next paragraph.
Now adjust the screw out-wards a turn or two. Pull the trigger lightly until the gun just fires, and try to hold that point. You should feel the RT kick against the trigger and reset it. Continue to adjust and shoot until you find the setting you like. Turning it out-wards makes the RT effect lighter and faster, up to the point where it doesn't work anymore.
If you can still pull freely after a dozen or so shots, degas your marker and head inside. Check your parts and check your install work against the instructions, because something is not right. Pull the piston out of its housing and see if it has grease on it. If not, give it some lube (not oil) like some Dow33. Make sure you have the air line on right as well. Once everything checks out, start the test again.
The A5 isn't too scary once you get it apart. If you have the parts diagram from the manual you should be fine. It might be a pain the first time though, but it gets easier.
I'd wait for other people's input here, you can also look at the a5 owner's website- Tippmann A5 Operator Group a paintball forum for the Tippmann A-5 Marker Owner.