I think you need change separator to ,\s+ - it means comma with one or more whitespaces:
df = pd.read_csv(filename, sep=",\s+", engine='python')
Sample:
import pandas as pd
from pandas.compat import StringIO
temp=u"""imeStamp, Label, VarName, Data
2017-03-09 13:03:20, USER_INPUT, Name, Test 1
2017-03-09 13:03:20, USER_INPUT, ProjectNumber, 04BGA
2017-03-09 13:03:20, USER_INPUT, PasteType, Senju F100
2017-03-09 12:03:20, CASETTE_INFO, CassetteHSPGetEjectorFeedAdjust, 2,2,2,2.4,3.5,1.15,1.1"""
#after testing replace 'StringIO(temp)' to 'filename.csv'
df = pd.read_csv(StringIO(temp), sep=",\s+", engine='python')
print (df)
imeStamp Label VarName \
0 2017-03-09 13:03:20 USER_INPUT Name
1 2017-03-09 13:03:20 USER_INPUT ProjectNumber
2 2017-03-09 13:03:20 USER_INPUT PasteType
3 2017-03-09 12:03:20 CASETTE_INFO CassetteHSPGetEjectorFeedAdjust
Data
0 Test 1
1 04BGA
2 Senju F100
3 2,2,2,2.4,3.5,1.15,1.1
If 1.solution does not work use separator which is not in data - ¥ or | and read all data to one column data. Then use str.split:
import pandas as pd
from pandas.compat import StringIO
temp=u"""TimeStamp, Label, VarName, Data
2017-03-09 13:03:20, USER_INPUT, Name, Test 1
2017-03-09 13:03:20, USER_INPUT, ProjectNumber, 04BGA
2017-03-09 13:03:20, USER_INPUT, PasteType, Senju F100
2017-03-09 12:03:20, CASETTE_INFO, CassetteHSPGetEjectorFeedAdjust, 2,2,2,2.4,3.5,1.15,1.1"""
#after testing replace 'StringIO(temp)' to 'filename.csv'
df = pd.read_csv(StringIO(temp), sep = '¥', names=['data'], skiprows=1)
print (df)
data
0 2017-03-09 13:03:20, USER_INPUT, Name, Test 1
1 2017-03-09 13:03:20, USER_INPUT, ProjectNumber...
2 2017-03-09 13:03:20, USER_INPUT, PasteType, Se...
3 2017-03-09 12:03:20, CASETTE_INFO, CassetteHSP...
df = df.data.str.split(',', n=3, expand=True)
df.columns = ['TimeStamp','Label','VarName','Data']
print (df)
TimeStamp Label VarName \
0 2017-03-09 13:03:20 USER_INPUT Name
1 2017-03-09 13:03:20 USER_INPUT ProjectNumber
2 2017-03-09 13:03:20 USER_INPUT PasteType
3 2017-03-09 12:03:20 CASETTE_INFO CassetteHSPGetEjectorFeedAdjust
Data
0 Test 1
1 04BGA
2 Senju F100
3 2,2,2,2.4,3.5,1.15,1.1