Please help. 545i bmw

I hope the white smoke does not have a sweet smell to it, that would indicate a intake manifold leak or bad head gasket or cracked head. Are you loosing coolant? Here is info on the codes...P0491 BMW - Mass Air Flow Sensor Low Flow Limit Detected Bank 1...Possible causes; Lean air/fuel ratio-Low fuel pressure, Failed HO2S11, Vacuum leak on engine.......P0492 BMW - Mass Air Flow Sensor Low Flow Limit Detected- Bank 2...Possible causes; Intake leak, Damaged AIR system components, Faulty AIR Solenoid Valve, Faulty AIR system relay.

I was told by the seller that seafoam was used. I checked my oil cap n Oil dipstick and had no signs of milky oil and my coolant color was normal..could a bad catalytic converter be part of this issue!

On the seafoam, how long ago was that used? If he sucked it up into the engine via vacuum line just before you got the car, it would produce a lot of white smoke, and not have a sweet smell to it. Just driving it a bit would clear it out... A catalytic converter would be hissing, and holding back the engine, plus glowing orange when it gets hot. You can have a coolant leak into the cylinders without it getting into the oil. So what does the exhaust smell like? Is it a sweet anti freeze smell?

There is not a sweet smell to the smoke...and also only the left side of the exaust blows out..the right side does not. When we test drove the car it didn't have the white smoke... I added oil the day after and the next day the smoke began

Is it a blue smoke? Does it smell like oil? I hope you didn't get a oil burner.

No..its not blue...its white smoke

Ok then, the vehicle just may need to be run. So at this point all you have to do is take care of that Mass Air Flow Sensor problem. You may want to take it to a shop for repair. The white smoke should clear itself out from driving the car.

The wight smoke most likely are exhaust valve seals the code are for left and right bank air injection for your cats on warm up usually it's an easy fix most likely a vacuum line problem does it smoke after idle or all the time?

It smoke when ever you press the gas!!!

Just changed the oil today... the smoke comes out with the car is idling ! Not so much when you accelerate!!! Any ideas now?

Does the white smoke still come out after taking it for a ride, getting the engine warmed up, then at an idle is it still coming out? Have you taken the care down the road and clean the engine out by fast acceleration? It is important to know what the white smoke is, coolant, oil, or just condensation.

Only when it idles it gives the white smoke..when I drive it there is no white smoke

Common problem your exhaust valve stem seals are leaking oil throw the valve stem you could use 10w 20 and lucas additive oil that should stop it smoking or have the exhaust seals replace

answer to your code p0491 and p0492 is the air ports in the cylinder head are block with carborn,the only way is to look for a shop that has the tools to clean the ports,or remove the engine much much simple that way but cost around $6000.00.Please gentle man have any bmw 545i inspected for that code before you buy it is a very common problem after 180000km

I have a bbw 531i give out white smoke with the smell of coolant on it

Gangan did you ever find the problem?i have the exact same car with same problem