Senate candidates Lee Fisher (D) and Rob Portman (R) aren’t making much progress with undecided voters, a new Quinnipiac University poll shows.

The poll showed the race remains close, with 42 percent of those surveyed favoring Fisher and 40 percent saying they prefer Portman.

“Even though Fisher has been a figure in Ohio politics for two decades, 54 percent of voters say they don’t know enough about him to form an opinion,” Peter A. Brown, assistant director of the Quinnipiac University Polling Institute, said Wednesday. “For Portman, 66 percent can’t rate him. With four months until Election Day the Senate race is wide, wide open.”

The survey of 1,107 voters was conducted June 22-27 and had a 3-point margin of error.

The survey was released as Vice President Joseph Biden was heading to Cleveland to raise money and campaign for Fisher.