The still_needing_petrol_to_cool_injectors is something I've heard somewhere which kinda makes sense but like you have never wanted to find out by running out of it! The same idea had run through my mind a couple of years back and it was my searchings then that put a stop to it.
There was a chap called 'Kees' username 'kver' that used to offer much help over on
http://answerweb1.askanowner.com/qa/...=15657&page=10 His website is
http://www.verdampere.nl/ he used to answer all kinds of questions re LPG going back several years.
I'd love to know what causes it and what, if anything, it does to the LPG fuel economy. I'd join in in a practical way but work is a bit mad at the mo and there's another more pressing problem with the car that needs finding before I figure why the need for so much petrol. I don't know the physics /layout of the petrol injectors to offer another guess as to what's going on. To put a level head on ...I'd say - if the fuel system remains pressurised and it's been pumped round the system to cool it, and the petrol doesn't leak out anywhere or build up it must be being burned. Therefore the injector valve/valves leak. Next question - do petrol injector valves leak with time on Volvo S?? models? The people running petrol_only would never see this as it's masked by the normal operation. And even so i'd guess it would be compensated for by the petrol ECU as it would appear as a long term offset.
I'll have a search the other forums to see if I trawl anything up.
One thing is for sure - It was never there when new!
Google translate has been most useful for all kinds of things. :-)
Edited to add: After perusing the Haynes guide (and it's not the best for the bifuel S40) and a cup of tea, it would seem not a bad job to remove the fuel rail and the injectors. And if it were me, I'd jig them up so that small quantity of fuel could be sat on top of them and then I'd pressurise it to the quoted 44psi at which point it'd similar to the car. Then watch for, and if applicable measure, the leak. Can't do it just at the mo. Anybody out there fancy a go?