What was found
AFTER LIFTOFF, THE COCKPIT FILLED WITH A NOXIOUS, VAPOR, THAT BURNED THE EYES. THE PRESSURIZATION SOURCE KNOB WAS SELECTED TO OFF AND THE CONDITION DID NOT WORSEN. IT WAS THEN SELECTED TO RIGHT AND THE CONDITION IMPROVED. INSPECTED PLUMBING ON LT SIDE. NO DEFECTS. NOTICED THAT THE LT ENGINE WAS JUST REPLACED AND SUSPECT ODOR IS COMING FROM NEWLY PAINTED ENGINE, RAN ACFT AND ODOR EVENTUALLY DISSIPATED. OPS CHECKED GOOD IAW MM 36-11-00 AND 21-51-00.