LPG problems

Firstly what is a Zafira? sounds like an Arabic car? 4wd?
Might not be LPG specific but the LPG mob probably hacked into the vehicles electrics to dual fuel it.
Might be best to speak to the bods that actually fitted the LPG conversion.

An acquaintance had a similar problem on vehicle and after a lot of investigation we found the LPG bods had tapped into the wiring with those scotchlock things and as the wiring was very light it had actually, eventually cut the wire they had used as a power source.

Tony B5,
Problems with LPG fuelled cars are either simple or serious. Lets start with the simple ones. LPG is fed from the tank as a liquid to a regulator near the carby, and a good installation will have this lower than the header tank of the engine so water from the radiator can heat the liquid and turn it into gas. Check that the radiator is full,if it is not this will pevent the car from starting and if it is low on fluid cause fuel starvation.
Next stop the fuel solenoid should activate when the key is turned to provide liquid to the regulator, if it getting current (or opening with an audible click ) then the issue is serious.
Sometimes refinery gas as opposed to that extracted from the Natural Gas stream has a waxy content an a build-up will clog up the regulator,it need to be removed and cleaned or replaced.
There is not much else to go wrong with a basic LPG Auto installation unless it is a direct liquid injection type which are not very common.
Hope this helps
TTD

Id go with Peter on this, first the lights not coming on. Alot of gas fitters use dogy crimp fittings & dreaded Skotch locks, have seen them partly cut a wire to have it break later. I would be going over all the wiring conections where the gas wiring is cut into the vehicles wiring.

Yes a pommy car!! :-)
Part of vauxhall who also do the vectra.

Thanks for your tips all, we are on with checking the wiring for LPG connections, have checked coolant. Will let you know how we get on.