Hello, wondering if any of you Komatsu guy's can help. I have a FG50 with a Nissan TB45 propane engine that periodically backfires through the intake blowing the air cleaner cap off. This only occurs under high revs when lifting,never when travelling.
I have went through the basics (fuel spark wires cap rotor plugs timing valves etc) but can't seem to pin point it. it doesn't throw a code and only seems to do it once a shift (once is to many) regardless of operator. This unit is run very hard though.

Any thoughts would be appreciated.