Vcc=2.7v, pull up resistance=100KΩ, product will stop work; But when change pull up resistance into 20KΩ,product start to work again. change pull up resistance into 100KΩ, product stop work again.
Does the power is enough? When you pull up , may need more power,you can test the power consum. Or you layout have error , review you layout of the pull up resistance. The product you mean "sm card" or "sm card read"?
Added after 2 minutes:
if the product is "sm card",you can add power by outside to test it, and thought this you can find where is you error.
I think this is about you power and current, sm card get power and current from sm card read, so when you pull up resistant change to 100k, current change to small , at this time sm card can't get more current and power , so it will reset.