viper 5902 completed 1

It's my understanding that the virtual tach doesn't use any feedback from the vehicle, so chances are that isn't why the system is shutting down.

What happens if you start the car with the key, then remote start the car, then remove the key?  Does the car stay running or does it shut down?

I am new to all this and can't find an install manyal for the 5902 but It almost sounds like the remote start is not getting the information about the vehicles battery. Have you tried to reprogram the virtual tach? I would look into the voltage sence becuase it sounds like that is where your issue is. Here is what my 5901 install manual says about your problems

The vehicle starts, but immediately dies.
1. Does the vehicle have an immobilizer? The vehicle’s immobilizer cuts the
fuel and/or spark during unauthorized starting attempts.
2. Is the remote start programmed for virtual tach or voltage sense? If so, the
crank time may not be set high enough. Voltage sense does not work on
some vehicles.
3. Check diagnostics. Sometimes a shutdown becomes active during cranking
or just after cranking.

• The vehicle starts, but the starter keeps running.
1. Is the system programmed for engine checking off or virtual tach voltage
sense? When programmed for either of these features, the engine cranks
for the preprogrammed crank time regardless of how long it takes for the
vehicle to actually start. Adjust to a lower cranking time.
2. Was the Tach Learn successful? The LED must light solid and bright to
indicate a successful learn.
3. Make sure that there is a tach signal at the PURPLE / white tach input wire
of the remote start. If there is not a tach signal, recheck the connection to
the vehicle’s tach wire and make sure the wire is not broken or shorted to
ground leading to the remote start.

• The vehicle starts, but only runs for 10 seconds.
1. Is the remote start programmed for voltage sense? If this does not work, a
tach wire should be used.
2. Check shutdown diagnostics.
• The climate control system does not work while the unit is operating the
vehicle.
Either the wrong accessory wire is being energized or more than one ignition
or accessory wire must be energized in order to operate the climate control
system.

Also here is the shutdown diagnostics for the 5901 you will need to cross reference to the 5902

Shutdown diagnostics
To perform shutdown diagnostics:
1. With the ignition OFF, press and hold the Valet/Program switch.
2. Turn the ignition ON and then back OFF while holding the Valet/Program
switch.
3. Release the Valet/Program switch.
4. Press and release the Valet/Program switch. The LED flashes to report
the last shutdown for one minute or until the ignition is turned on, as
shown in the following table:
LED Flashes Shutdown Mode
1 flash Runtime expired
2 flashes Over-rev shutdown
3 flashes Low or no RPM
4 flashes Transmitter shutdown (or optional push button)
5 flashes (+) Brake shutdown
6 flashes (-) Hood shutdown
7 flashes Timer mode/Turbo mode/Manual mode error *
8 flashes Neutral safety shutdown
9 flashes Low battery (voltage mode)
10 flashes Alarm triggered **
11 flashes Wait-to-start input timed out
* Timer mode error: Ignition is on or shutdown input is active when activating
timer mode.
Turbo mode error: Turbo mode is programmed off, engine is not on or
shutdown input is active.
Manual mode error: MTS mode not enabled.
** Alarm was triggered during remote start sequence.