I've read this thread with interest as you seem to be experiencing similar problems to myself.
A while back I tried to write an automated FX trading bot to trade any CCY pair - but I concentrated on EUR/USD for my testing. I had about one year of tick by tick data which I downloaded from gain capital
http://ratedata.gaincapital.com/
With EVERY system - in backtesting they ran a profit for 60-90% of the time - sometimes spectacular - only to lose it all and more in a single week or two. The only way to protect against this was to lower the agressiveness of the money management which then meant that the bot's profits were far less than I can get swing trading (which is how I currently trade at the moment).
I tried tweaking the models - which invariably led to more parameters - which resulted in over-fitting to a set of data (I always back tested with different data to which I used to optimise the algo) or the bot got to the point where it would go a week without opening a trade. In the end many of them had so many parameters it was impossible to manage.
I tried loads of systems - here are the ones I can remember....
1. A combination of schotastic and RSI indicators, tweaking the buy/sell levels
2. Simple moving average crossover, tweaked to look at rate of change of the moving averages and other friggs.
3. Tweaking the moving average so that the less the price moves the fewer periods it uses to calculate. It means the moving average keeps up with the actual price better when there's a big move.
4. Looking for trend chanels in the price movement. When the channel has reached a pre-determined length the trade is opened (if the channel points up or down enough) The price is then monitored and when it jumps out of the channel the trade is closed.
5. Swing trading using tick/1min/5min data. Looking for higher highs & higher lows, or lower highs lower lows.
6. Opening a tiny buy & sell on every tick change, no stop but a take profit order a few points away. Runs up fantastic profits on a ranging market. However if it's trending sharply up or down kiss your account goodbye. Tried techniques of limiting exposure in a particular direction but it didn't stop the rot.
7. Trying out Gann theory on 1 min and 5 min data.
Anyway I wish you luck - I've given up on the bot - I'm now a discretional swing trader using EOD data. I find it stress free and simple to manage my risk while still gaining a respectable profit.