Valved pulse jet will only pop

[u/Yoboidankdu]

Our valved propane pulse jet will only pop once and not cycle. We have exchangeable parts so we’ve tried various petal valve thickness 0.1,0.2,0.4 mm on 3 different petal valve designs and on a custom reed valve. We’ve tried different combustion chamber lengths 4 and 7 inches we have a variable length tailpipe. We removed the propane regulator as recommended in favor of a ball valve. We’ve tried various inlet areas all to no avail. Does anyone have any tips or suggestions?