What was found
DURING THE TAKEOFF ROLL, SMELLED SMOKE. FIRST OFFICER SAW SMOKE COMING FROM THE CAPTAIN SIDE OF COCKPIT. CAPTAIN REJECTED THE TAKEOFF ROLL & RETURNED TO THE GATE. AFTER INSTALL OF NEW START VALVE ON NR 1 ENG, APU BLEED WAS APPLIED TO THE AIRCRAFT AND #1 ENGINE AUTO ROTATED. START SWITCH WAS IN OFF POSITION & ENGINE BLEED WAS OFF, BUT ENG AUTO ROTATED ON 2ND ATTEMPT. CYCLED NR 1 ENG START SWITCH AND ENGINE DID NOT AUTO ROTATE. POSSIBLY THE CAUSE OF FUMES BACK BLEEDING INTO THE PNEUMATIC SYSTEM. R & R NR 1 ENG STARTER SWITCH IAW AMM 80-11-00. INSTALLATION TEST IS GOOD IAW AMM 80-11-00-730-801-F00. PERFORMED ENG RUN OF ENG 1 IAW AMM 71-00-00-800-808-F00 FOR 5 MINS. ENG RUN WAS SATISFACTORY.