Hi,
If you look here, these are the basic components for the Koltec system. Look at the EGI drawing. I think, that may be closer to your type of system and you will have the EGI distributor. The Volvo has an integrated LPG and standard ECU rather than seperate units for each fuel. The diagnostics test does not work for the Volvo's.
http://www.my90.co.uk/lpg/album_pers...hp?user_id=500
This site is a good place to start. More applicable from halfway down the page.
http://www.juliantrubin.com/encyclop...ering/lpg.html
I'll P.M. you a link on how to clean your EGI distributor, if you have one of this type.
Best Regards
PJPJ