First of all check all wiring on engine for shorts or breaks. Special attention to wire breaks at connectors. Turn on keyswitch and listen for a click meaning the LPG lockoff is working. If not then check for broken wire on the LPG pressure sensor then relay ( second going inboard) next to fuse block. Then listen for LPG being dumped into throttle chamber with KOEO. If fuel is being dumped then an injector holder is probably needed if the main injector isn't stuck open or stuck assist injector. Cut switch off and listen for a high pitched sound with a little clicking coming from throttle chamber for appoximately 3 seconds. If throttle chamber is not making a sound then check fuses for ETC and relay for ETC. Also check fuse thats located on injector pigtail. If all else fails then contact your local Cat dealer who should have the software to get readings from different sensors and have you up and running in no time.