2000 chevy blazer tach problem

i have a 2000 chevy blazer ive put a remote starter and alarm from crimestopper cs-2014DP-TW2-FM. When i use the tach wire from the red prug my tach in the dash starts acting up. Even wheni go ahead and put the key in still does that. Is there something wrong or why would it do that?. im also using idatalink ADS-DLSL-GM. it also has a tach wire. I use the idatalink wire got it to work but when i start the car with the 2way pager looks like the starter gets stock on cranck and wound start.