dont want to stay running

i installed  viper 5101 to my 03 ford explorer.  everything worked fine until last week when it got so cold..  when u use the remote start it only stay workin for 5 seconds and turn off.

I tried to reset the vertual tach like it says in the manual:: nothing happen

i connected the tach wire to the coil pack and do the learn tach .. nothing happen...ps: it will not let me do the tach learn at all when it cold..

need help dont know what to do..

While your problem sounds like a voltage sense or tach issue here is another possibility...

What type of bypass did you use?  The older bypass like the PKU-F2 or 556SW were sensitive to low temperatures and not reliable in cold weather...

The PKALL is a good unit so that is not your issue.

I am not familiar with the Viper unit, but on the tach wire, here are some locations:

1.) Any wire that is NOT WHITE/ PURPLE or RED   @ IGNITION COIL PACK 

2.) Gray wire at PCM module

3.) TAN/WHITE on 4.0 LITER  AT IGNITION COIL

Good luck!

whatever i do the remote start dont want to learn the tach.. maybe i've been doing something wrong..

start the car with key and then hold the Valet/Programswitch.

. After 3 seconds the LED light should comes on when the tach signal is learned, but it never light up..