subs and gas tanks are safe as long as there are no shorts and gas leaks , faulty wiring is the headache thou poorly insulated and routed wiring seen many amp power wires run thru a poorly cut hole in the firewall with no insulation around the wiring or a grommet in the metal . 16 years doing gas conversion i have welded shields on tank straps when the gas tanks are full or even half full and im still here today , even welding exhaust systems or body panels with a gas tanks installed never had a problem , Biggest causes for back firing when on gas can be the base engine tune , checking spark plug leads and plug gaps , check manifold gaskets for vacum leaks , injector seals for swelling or shrinkage , EGR valves for leaks or punctured diaphragms , stalling problems can be related to incorrectly placed balance line or lack of balance on the convertor , incorrect tune settings weather it be software settings or to lean or rich at idle , once these have been looked at then you can start looking at the gas convertor and the mixer set ups , Electrical connections may look good from the outside but lack enough tension in the crimp to hold a good connection or to hold onto another connection , unsolder-ed wiring connections can corrode or if the wiring is simply twisted together and covered with tape after some use they can work loose , Poor installation and choice of equipment can lead to engine damage from poor running poor mixture control running to lean tends to burn out valves and over work the ignition system .
