Failed internal oil seal
blow by through the turbo ,my truck did the same thing had to get the turbo rebuilt
There could be many problems related to smelling gas and seeing white smoke from your tailpipe. Some suggestions would be the head gasket. If the smoke has a blue tint to it, it may be oil related. If your car has a turbo, it may be the turbo needing to be replaced. To be sure, you can have a mechanic do a diagnostic on it.
check the hose from the turbo to the air mass meter on the bottom of it may be burst very common repair or replace.
You have a blown head gasket. STOP running this engine or you will destroy it. The head gasket needs replacing.There might be another problem if you have a turbo. If so the smoke you see (if not pure white but a little gray with a burnt oil smell) might be oil leaking into the turbo unit and expelling through the exhaust. You would need to replace the turbo. Used ones for about $500 parts and $ 300 labor.
If you are loosing coolant, you have a leaking head gasket. If you are loosing oil and have a turbo, the seal on the turbo is bad. either intake manifold gasket or head gasket is leaking
it can be unburned fuel damaged turbo charger etc. light amount of smoke can be normal large amounts = problem.
I know the white smoke would be caused by coolant, which would be leaking into the combustion chamber.
White smoke out of exhaust is usually indicitive of water or coolant in the combustion chanber/ chambers of the exhaust. Usually caused by a blown head gasket. A costly repair. clean pipes to and from intercooler and clean intercooler .and clean crankcase breather.
Black smoke can be caused when there is an improper air to fuel ratio . This can be anything from a plugged air cleaner,injector,turbo....
White smoke is a symptom of a blown head gasket.
If the turbo is intercooled it may have a blown seal allowing coolant to pass into the intake flow. White smoke is usually an indication of a blown head gasket. Stop driving the car immediately until this is looked into. Serious engine damage will occur if th head gasket is blown. if is not the head gasket you are in for a cracked block or cylinder head $$$$$$ A blown seal in the turbo is a possibility. you could just be running to lean i blew white smoke when i used racing octane gas. also when i used octane booster of fuel injector cleaners. if it is consistent, probably head gasket.
White smoke is eaither a blown head gasket or you have water in the fuel system. This is not to be confused with flooding an engine and seeing white vapor coming out of the exaust in which that would NOT be smoke, it would be gas vapor's. If your burning oil, the smoke will be blue and smells of burnt oil.