Ammonia concentration at 3~4ppm is completely acceptable level for fishless cycling
. Once I have done it with 5~6ppm dosed daily, and it was still cycled in 6 weeks. If your cycle is completed with low level of ammonia dosed daily, you won't be able to full stock your fish tank when it is done. When the tank is cycled with 5~6ppm ammonia, you have the option to fully stock the tank at once.
The real toxic level (toxic enough to stall the cycle) is above 6ppm.
No change 14 days into fishless cycling is also completely normal. I have done multiple successful fishless cycling in the past. Without heavy seeding, it usually takes up to 3 weeks before there is any change at all.
If you want to speed it up, you can do the following,
1. raise temperature to above 80F
2. add extra air stone to increase oxygen level
3. heavy seeding. You can do it by getting Dr. Tims's (Tetra SafeStart). I have used it twice and it really work the wonder as a form of heavy seeding for cycling. Yes it is meant to be used for cycle with fish, but it certainly work for fishless cycling too. With Tetra SafeStart, the usual time for fishless cycling can be as short as a few days to a little more than a week even for high concentration of ammonia dosage.