Police said Tuesday that an analysis of the car that barreled down India Street and plunged into Portland Harbor on Friday showed no mechanical defect that would have explained the accident.

Ursula Nixon, 84, of Portland was driving when the Nissan sped out of control down the street, crashed through two chain-link fences, went across a parking lot, crashed through a guardrail and plunged into the water.

Police, firefighters and some civilians jumped into the water to rescue Nixon. A civilian, Katie Nelson, helped pull the woman out of the driver’s seat to where a firefighter could grab her and get her to shore, city officials said.

“There were a few of us at the car (initially). We didn’t really know how to get her out,” said Michael Wells, who was on a break from his job at Auto Europe. “One small (woman) could get in through the window. She got her (partially) out and the car was sinking not too long afterward.”

The City Council plans to honor the people who helped in the rescue at its Oct. 15 meeting.

Nixon was taken by ambulance to Maine Medical Center, where she was treated for non-life-threatening injuries to her femur and the bones around her eye, said her niece Mary Ledue-Paine.

“Her only worry when she got out of the water was did she hurt anybody,” Wells said.

Ledue-Paine said her aunt has always been a cautious and safe driver, the one who brings her friends to their doctor’s appointments.

Police said the small sedan has an electronic throttle, so no cable stuck. They will next analyze the “black box,” a small computer that records information about the car’s performance, to determine whether that indicates a malfunction.