Astroflex 4204u remote start problem

Hi, I bought a my pickup (2005 Silverado 1500)awhile ago and I found out that it had a astroflex 4204u auto starter installed, but the auto dealer did not have the remote for it. I recently bought a replacement remote and tried programming it and seemed to get it all working except for when I to remote start it. The pickup will turn over and try to start, but won’t start. It does have a bypass unit on top of the 4204u unit. it is a gmdl-bp so I don’t know if that has anything to do with it. The 4204 brain was blinking 12 times, not the bypass. The bypass was blinking 6 times, but I got that programmed for my model of vehicle already. It still is not working though, The unlock and lock feature works fine, just not the autostart. Any kind of help would be great. I do have a dealer nearby that works with astrostart, just wanted to see if I could do it myself before paying for it to be done.