Heat Dependant production

My current HHO cell I have in my truck uses stainless washers as plates spaced 1/16" apart and it is the first cell i have made that I have ran into the issue of it producing very little HHO when first activated but after it heats up to about 38C it produces about 6LPM. Is it an issue with my electrolyte(Sodium Hydroxide-Lye) or what. I do not currently have a PWM.

Also I have my MAF Enhancer setup and it runs great well i am going down the road but when my generator reaches between 4-6LPM I experience detonation in my pistons causing my ECU to take over from my MAF and increas my Fuel:Air ratio.

Any Suggestions.