Printing first layer too thin

I have built my first Reprap (Mendelmax) and am printing with 1.75mm PLA. I have a J-head hot end with a 0.4mm nozzle. I have calibrated the extrusion motor so the feed rates are correct. When I print, it seems as though too little material is being extruded. The first layer looks like dashed lines on the glass bed. By the time we get to the 2nd or third layer, nothing is coming out of the extruder and you can hear the extruder bolt spinning and not driving filament down. I clear out the extruder and repeat the process again. Any suggestions?

Is your nozzle hot enough? Try increasing the temp a bit, the temperature that your sensor is measuring isnt always the same as the actual nozle temperature.

I have the same issues when my first layer is too close to the glass. I have my first layer at .3mm

Thanks for your help. I am not exactly sure what fixed it but I did a few things:

increase extruder temp to 205C
Set my Z-axis home closer to the plate. An index card feels some resistance when placed between tip and glass.
Set extruder diameter to actual diameter of 0.4mm
Made sure to get a "running start" by forcing some filament through the extruder, then tightening the hobbed bolt and zero the extruder axis.

Then I printed an object! I need to do some tuning as some of the fine details ended up looking hairy.