Help, my car won't start!

My Passat 35i, manufactured in 1995, with engine code 1Z, won't start. The starter motor turns the engine over, but it doesn't fire up. About one out of every three attempts to start it, it briefly fires for about 2-3 seconds and then dies or doesn't really start at all. When this happens, white smoke comes out of the exhaust pipe, which smells strongly of fuel. Please help me with this problem! Thank you!!

I suspect the crankshaft pulley gear (loose or damaged). Set the engine to Top Dead Center (remove the rubber plug in the transmission). Remove the upper timing belt cover. Now, check if the alignment pin aligns precisely with the hole behind it (you may need to rotate the engine by about 180 degrees). Use a suitable pin or simply look with a mirror. If the holes are offset by approximately half the width of a hole, then the crankshaft pulley gear is definitely the culprit.