SpudFiles

I used this idea in a combustion cannon. It does not have a ball valve. I have it rigged up with elastic bands to return it to the starting position. i would put pictures on but I cannot get them of my phone at the moment

You've ignored the question as to the meter volume you're using, thus making it impossible for us to help you any further.

1/2" pipe, 3.5" long with a pressure of approx. 90PSI but it won't fire at that (what ultimatespud calc spit out) if I go down to like 25PSI it'll fire though.

These are before the meter got put on. I just found the converter I needed to get pics off of my phone, I will try to get a exact measurement and pic of propane meter. I think the problem lies in the fuel not getting mixed properly.

Going by those dimensions, looks like you want about 65 psi for an ideal mix.

Does your meter gauge read zero at atmospheric pressure? If so, for a purged meter you need about 50 psi.

yes at atmospheric pressure it reads zero

Can you describe your metering procedure in detail?

Alternatively, can you just buy a 50mL syringe and solve all your problems

How well does your ram seal? It looks like a loose fit. You'll lose efficiency if it leaks.

As for the combustion issue, fan or no fan, you should be seeing better results. Most of the time it's too much fuel. Keep trying less fuel after proper ventilation each time.

i had a simalar issue year ago when combustion was the addiction. try changing the barrel/chamber ratio. if the chamber is too big the barrel will act as as choke. some pics would help us diagnose this better.