Bicep Fatigue but No Pump

Hello Sir, While performing bicep curls and its variations , I tend to get pump in the 1st and 2nd set of the first exercise but after that in the successive sets there is no pump but the biceps gets fatigued and i am unable do perform any more repetitions . This problem of getting muscle fatigue but no pump is mainly in biceps but sometimes it also happens in abs exercises .
Please guide me to overcome this problem.