Is it really defective?

The car is a '02 Honda Accord 2-door. The alarm is a DEI Python 871XP. The options added were the 516U (voice siren) and 508D (field motion sensor). The voice part works great, except for it on occasion says the door was tampered with when it's been remote-started. The real issue here is the motion sensor. We started with a Clifford piece that had horrible range. Literally would not trigger unless you put your hand on top of it. We then upgraded to the 508D because in past installs it worked like a champ. Not so now. I have 12v to red, a perfect ground, the green and blue wires together to the green of the shock sensor as instructed by Directechs. I have already defected 2 of these out and putting the 3rd in tomorrow. Any advice?

you have to disconnect it during remote start. contact dei