Don't risk it - they'll almost certainly refuse you entry...
This is in the FAQs on the eTA website:

My application for an eTA was refused. Can I still travel to Canada during the leniency period?
If your application was refused, you should not plan or undertake any travel to Canada, even during the leniency period. If you decide to travel to Canada with a refused eTA during the leniency period, you may experience delays or be prevented from entering the country.

We encourage you to reapply for an eTA only once you have addressed the reason(s) leading to the refusal of your application.