On March 5, 1994, about 1457 eastern standard time, a Piper PA-28-161, N9134A, registered to Air Orlando Sales, Inc. crashed shortly after takeoff while practicing touch-and-go landings at the Sanford Regional Airport, Sanford, Florida, while on a 14 CFR Part 91 instructional flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the certified flight instructor (CFI) and student pilot received minor injuries. The flight originated about 1 hour 24 minutes earlier from Orlando Executive Airport, Orlando, Florida. The flight departed about 1333 and performed maneuvers then flew to the Sanford Regional Airport where the student was to perform touch-and-go landings. After the fourth or fifth touch- and-go landing during the upwind leg with the student flying the airplane, the engine experienced a loss of power. The CFI took control of the airplane and landed on the runway but stated that he was unable to stop on the runway. The engine power was restored after he cycled the auxiliary fuel pump. He elected to take off but the engine lost power again. During the turn to return for landing, the airplane stalled and impacted the ground nose and left wing low. The student pilot stated that the fuel selector was not moved at any time during the flight. An FAA inspector arrived at the accident site about 3.5 hours after the accident and examined the airplane. The inspector stated that the left wing was damaged and the fuel line was broken near the wing root area but there was no fuel leakage. The fuel selector was in the "off" position but before being moved it was in the "left" position. He also examined the left wing fuel tank and there was no evidence of fuel inside the tank. The right wing fuel tank was drained and found to contain about 15.4 gallons of fuel. Power was applied directly to the auxiliary fuel pump terminals and the pump was found to operate. The engine-driven fuel pump was removed from the airplane for bench testing and found to operate normally. According to the owner of the airplane, the airplane had been operated according to the Hobbs meter for 5.1 hours since the fuel tanks were filled.