The mixer was swapped with a good running truck and the engine runs a few seconds then backfires. If I install the mixer from the faulty truck onto to good truck, it wont run. I`d say the mixer was blown from the backfiring. I need a new mixer for sure but the engine still has a miss and backfires. the only thing I didn't do was unhook the exhaust and try it. Possible blockage....an engine will start with a blocked exhaust but snuff out soon after...and backfire through intake. will try tomorrow.
just wondering if the hyd valves are not opening enough...would that cause backfire...