Corny Wont Carbonate

Hey guys, ive been reading up on this but nothing seems to match my problem. I've had a corny in the fridge for 5 days at 13psi and 3 degrees. I tried it and little to no carbonation in the beer. Then I bumped it to 20psi for 2 days and still nothing. Today I had it at 40 psi and as of now still no results. There's always more than enough to push the beer and a large amount of head but never any true carbonation.

What might I be doing wrong?

Cheers

I think you are pushing the beer too hard for your beer lines. You might have a really well carbonated (if not overly carbonated) beer but you are losing all of it in the pour. Try relieving the pressure, dialing it down to 8 psi or so, and if the beer won't come out, slowly increment up until you get beer, but not a lot of head. Unless you have beer lines a quarter mile long, 40 psi is way too high to try to serve. Hope that helps.