Problems with homing

I just finished building my own 3D Printer with threaded rods on all axes. Now i wanted to set up the software but i have some problems with the homing function in pronterface. I can move the axis one by one and everthing runs smoothly. I can also home the z-axis without problems. But when i try to home x or y the steppers start to make horrible sounds and i turn them off because i fear they might brake.
I dont really understand why I can home the z-axis just fine while the other two make this horrible sound and why they even make that sound because the run smoothly when i move them manually via pronterface. Does anybody have any suggestions? (Max feed rate is the same for all axes, v_ref on the drivers is roughly the same also)

You have a different homing speed set in the firmware.
Try to adjust it and/or vref until it sounds good.

The Problem was indeed in the Firmware. Thanks a lot. Still have to find good feed rates and accelarations for the x-axis which has to carry a lot of weight

Ok now i have another problem. After playing with the Parameters i found a setting that fits my 3d Printer well. When i homed the axes everthing went smooth and quiet.
Next i wrote a small g code to test some basic movements. The first command was G28 for homing. The z-axis didnt cause any Problems but when the y-axis started to move it went into the wrong direction at first, then it started to go back and forth. It looked like the g code was trying to move in the positive direction while pronterface wanted to move in the negative direction (My homing pos is z_max, y_min, x_max). I quickly unplugged the power supply and resarted the printer. Now the stepper for the y axis wont move at all and just makes weird sounds. I already lost a stepper in a very similar way so im scared that i broke another one.
Any ideas what has happened or how to get the stepper to work again?

Hi MilloMille, the problem with your y-axis homing suggests that maybe the direction pin of the motor control ic is floating*. Is the Arduino plugged into the Ramps board ok?
Dave

*floating = not driven to either 0V or 5V but wandering in between. You probably already know that.

Thanks gbr but i alreasy "fixed" it. After the described Problem i was scared to use the G28 function again so before every g code i homed the axis in pronterface. I changed a lot of settings in the firmware, mostly feedrates and acceleration. After a few days of testing i decided to stop Play chicken and try the G28 command again. Since then i never had trouble again.
Since i changed a lot of settings i can't say for sure what fixed the Problem but ym guess would be that the accelaration or jerk was set too high.