viper 971xv 2008 sierra remote start

I had this alarm professionally installed by Tweeter on my 2001 Jeep Grand Cherokee. It seemed the only unit I had to swap was the databus module from 455J to the 1701GM in order to be compatible with my 2008 Sierra. So far I have the alarm/door locks/motion sensor/shock sensor all working. But whenever I try to start up the vehicle with remote start I can hear the gas pump turn on and the relay in the 556U turn on. The system tries 3 times then gives up. Every time it turns on I see the check engine light come on. Looking at the wiring diagram provided here I see that the white wire is for the starter. The only strange thing is that it hovers at 5V. Where my Jeep was 0V and 12V when trying to startup. I even added the 1300 ohm resister in-line to the engine side but still no luck. My gut tells me either I'm on the wrong wire or the 556U isn't compatible with my Sierra. Does anyone have any ideas what I could be doing wrong? Thanks in advance!!!

After a bit of searching.... I found this useful tidbit of information. [quote]as long as your remote start ign and acc wires have the correct timing output( acc first ign 2nd, acc drop while maintaining ign, ( as my audiovox and d.e.e. do) i just put a key in a universal box( keys from transponder island or hwoard keys less them 10 bucks and a u is around 15) very simple truck to do if remote start has right sequence, test one by wiring it up and just leaving key in ign barrel if it starts then you have right timing just need keys and universals[/quote] So I now have the starter working.... but it dies immediately after....

Did you relearn the tach ?Nissan Master Tech.

Thanks for the tip! It worked once I set the Tach for Voltage Sensing.