smartstart with 09 mdx

i installed a Viper SmartStart 3000-series into my 2009 Acura MDX over the weekend and everything were good except for my car doesn't relock itself after remote starting. Well, it sometimes relock itself and sometimes doesn't. i ran arm and disarm wire into the door and also used a 451M module for the positive door lock wires and also ran those into the door. everything works, except that sometimes the car doesn't relock itself after remote starts. i used virtual tach instead of running a tach wire and i don't know if that makes any difference. can anyone suggest what i should do next?

Does it only re-lock when you lock it with the smartstart and not the factory remote? If yes, I think there's a simple answer.

not the case, because i also lock my car using the factory remote. the only time i use the smartstart app is for remote starting and nothing else

I believe what beegbie was getting at is your factory fob does not work while the engine is running. This is a factory designed feature (read problem). I am only familiar with the clifford CS3000 smart start but it should be similar to the viper. I do not know of a relock after start option in those units. Only relock after shutdown. I have been told by many the only option is to relock using the smart start app after you see that the car is running. If the car does not respond to that lock command while the engine is running you will have to find a wire that does respond. Make sure the actual door lock button on the door itself operates while the engine is running. Start there. Only use that wire for lock not unlock, as it will not disarm the factory alarm.To master and control electricity is perfection. *evil laugh*

the relock after start is a feature built into everything DEI remote starters. there is not a programming option for it because it automatic do so for cars that needs to be unlocked before start. i've work on DEI remote starters for years and it always work on all my previous installations. the funny thing is it sometimes does and sometimes doesn't work. if it never works then i come to believe that there is no such feature but it sometimes work that's why i ask. i do know that after the car starts only the lock/unlock function does work on the factory remote and the arm/disarm doesn't work also but the lock/unlock switch on the door works. i am able to lock/unlock the car with my smartstart app after it remote start.

The dei system will only re-lock if the dei system has been used to lock the car. Think about it... On all the other systems you've done, do the doors automatically lock every time you remote start the car? No they don't. They only re-lock if the dei system has been used to lock the car. Try it out. I'll bet you'll find that if you lock it with the smartstart it will re-lock every time. If you lock it with the factory remote, the doors will stay unlocked. A easy fix would be to run your -start wire (purple) with a diode in line to the lock wire on the 451m. This will ensure re-lock every time.