why is my tach input tied to gnd? 1400xpl

I bought an 05 Ford F150 through an auction and I find there's an python 1400XPL auto starter installed. the starter is acting very peculiar in that when i command a start from the remote it will only work if it has been recently running. I thought it was related to cold weather, but even on a warm day if the truck was not running in the last hour or so, then it will not flash the lights or attempt to start. I tried unplugging the relay satellite and the immobilizer bypass individually and in both cases, the lights do flash but of course it does not start. (this test done after a recent run and remote start functions with modules plugged in.) It is acting like the hood pin is grounding becuase this is how it acts with the hood open. so i followed the hood pin wire to the firewall where i was expecting an exposed wire but not the case. and i taped it up there just to be sure. but i noticed there is a second wire going through the grommet, a purple wire. and it is tied to the hoodpin ALSO. I traced back this wire to the tach input on the python module. Could the tach sense wire be feeding a gnd into the hood pin wire causing this????? once it's cooled down and I prove a no start condition, i will cut the purple wire but i must be ready to shut it down in the event that i have made a mistake and the motor keeps cranking.

any thoughts?

john

If the tach wire is connected to the hood pin AND the system is set to tach monitoring the system will never start. 

The remote start monitors the tach signal not only when cranking but also when running.  If the tach wire is always grounded or always open the system will shut down after X seconds (when cranking or when running). 

I would do like mentioned above and verify it wasn't a wire extension.  I would also check the programming - I bet it's set to voltage if there is no visible tach connection.

Does the truck have to actually start within the hour or can you simply turn the igntion on and then back off?  It almost sounds like it's a sleep issue but they don't typically affect remote starting (that I've seen).