Micro combustion problems...

[qwerty]

Here's the scenario:

So i fill my syringe with 2ml of propane, i inject it into the chamber (which has a barrel on with a BB inside) i then pump the syringe 6 times without taking it out the chamber, when firing i dont take the syringe out and get constant ignition but the BB never exits the barrel it sounds and feels like it ignites, gets forced halfway down the barrel then gets sucked back in.
Almost like it's making its own vacuum.

Any ideas whats wrong?

[jackssmirkingrevenge]

i then pump the syringe 6 times without taking it out the chamber

Por que?

What's your ignitor and how big is your spark gap? Are you injecting the correct amount of propane?

[qwerty]

Ignition is a bbq pezio spark gap is about 4mm and i'm pretty sure it's at optimal ignition as i've tried others with no successful ignition

Basicly there is a hole in the side of the chamber where i inject the fuel, but i pump it up and down 6 times before i click the pezio.

[jackssmirkingrevenge]

can you increase the gap to around 7mm and not pump the syringe?

[ilovefire]

how long is the barrel because if it is was to long then the gas starts to cool before the projectile leaves the barrel sucking it back, i have experienced it before and i think it even sucked the projectile back into the barrel after leaving

[jimmy101]

We need to know the chamber and barrel volumes.

Is there significant leakage around the syringe inlet port?

[qwerty]

Well i cut down the barrel and it fires now.

Just to make a mini hybrid now...

Off topic but is this right.

(not exact) for a 3x mix i would want %12 propane and 30psi?

[jackssmirkingrevenge]

(not exact) for a 3x mix i would want %12 propane and 30psi?

pretty much