New Boy

[>>Mart<<]

i found out a little bit about the sigma alarms for u

apparently they are connected(or should be) to the ignition the fuel pump and they also should be connected to the spark (for the spark plugs) which sounds like the problems you are having
there is no way of doing it really without getting a specialist out
i tried to find out what colour code the wires are but they are all black the only thing you could do is disconect the wires but when you do tag them so you know where they came from
up to you really but i would disconnect it or get a price for a new one to be fitted it would probably work out cheaper then getting the old one fixed

[gibby]

^ Or as it's only a month old, get the buggers out that installed it. 

[Agreeable Slick]

i tried to find out what colour code the wires are but they are all black

That would be so that anyone that tries to nick your car the clever way doesn't know which wire they are cutting. 

[Neaty]

i tried to find out what colour code the wires are but they are all black

That would be so that anyone that tries to nick your car the clever way doesn't know which wire they are cutting. 

good thinking batman