Help balance this chemical equation for me

I'm having a hard time balancing this chemical equation!
It's the combustion of ethyne, producing the products carbon, carbon dioxide, carbon monoxide, and water vapour.

C2H2 + O2 --> C + CO2 + CO + H2O

I can't get it balanced and it's driving me crazy!

3C2H2 + 6O2 --> C + 4CO2 + CO + 3H2O

That can't be balanced. What you've got is a mixture of three separate reactions:

2 C2H2 + O2 → 4 C + 2 H2O
2 C2H2 + 3 O2 → 4 CO + 2 H2O
2 C2H2 + 5 O2 → 4 CO2 + 2 H2O

You need more information to determine how much of each reaction actually happened.