[Ultracowman]

I want some advice on a potential issue I might have. A few months ago, I ripped out the emissions system to my 2011 335D. (EGR, DPF, SCR, Swirl Flap). Ever since then, when I cold start my car, a big plume of white Smoke will come from the exhaust. This isn't your typical startup fumes either, it's thick, white, and smells like burnt chemicals. It only happens when the engine is cold and been sitting for a while, and it appears to be less thick when it's warmer outside (I live in Wisconsin, so it's been consistently below freezing the past few months). And a few seconds after startup it's completely gone, and the exhaust smells like normal diesel stink. My engine doesn't appear to be eating oil, (level look good) and the engine never overheats, if anything, it is always running cool. The highest temp I have ever seen it get was 155 degrees fahrenheit. Before the delete, temps were substantially higher. Any advice on what might be causing it? I thought it could be condensation from the cold, but it smells absolutely horrendous and is thicker than water vapor so I'm at a bit of a loss.

[Master_Chase]

Originally Posted by Ultracowman

I want some advice on a potential issue I might have. A few months ago, I ripped out the emissions system to my 2011 335D. (EGR, DPF, SCR, Swirl Flap). Ever since then, when I cold start my car, a big plume of white Smoke will come from the exhaust. This isn't your typical startup fumes either, it's thick, white, and smells like burnt chemicals. It only happens when the engine is cold and been sitting for a while, and it appears to be less thick when it's warmer outside (I live in Wisconsin, so it's been consistently below freezing the past few months). And a few seconds after startup it's completely gone, and the exhaust smells like normal diesel stink. My engine doesn't appear to be eating oil, (level look good) and the engine never overheats, if anything, it is always running cool. The highest temp I have ever seen it get was 155 degrees fahrenheit. Before the delete, temps were substantially higher. Any advice on what might be causing it? I thought it could be condensation from the cold, but it smells absolutely horrendous and is thicker than water vapor so I'm at a bit of a loss.

As for the white smoke diesels don't have a complete combustion when they're cold. Look up diesel cold start videos on youtube.

You need a thermostat operating temp is around 90C or 194F (or it's just too cold there and you should block some airflow through the radiator). It's cooler after the delete because you removed the EGR.

[Ultracowman]

Thanks for the info! So in this case would you recommend blocking part of the rad to help the car to stay closer to operating temp? Do you know of a good way to do this?

[Master_Chase]

Originally Posted by Ultracowman

Thanks for the info! So in this case would you recommend blocking part of the rad to help the car to stay closer to operating temp? Do you know of a good way to do this?

The cheap way is cardboard and a nicer way is a grill cover. Make sure you don't block too much air or your the car will run warm and too little means it'll continue to run cold.

[nonford]

Dont even worry about it! Mine makes a plume when temps are lower than 50 on a first start of the day! Kind of like a badge of honor if you ask me!

[lnxguy]

So you ripped off all the emissions and are wondering why you're getting smoke during a cold start?

[Tomnavigator]

Ultracowman,
Where you live, a properly operating thermostat is essential. Many people report their temperatures never getting above 155 when their thermostats fail. The thermostats typically fail in the open position which causes the lower operating temperature. Your fuel mileage will also get better with a properly operating thermostat.
I recommend you replace your thermostat and water pump both. The reason why I recommend the water pump also is that the water pump is cheap and replacing both only adds about 5 minutes to the job. The thermostat housing bolts to the water pump. Water pump seals typically start failing around 100k to 150k miles and I am assuming you have never replaced your water pump.

[barf]

The smoke is normal when it's cold, uncomplete combustion as someone previously stated, gets better after cylinder has heated up a bit. You probably deleted catalytic converter along with DPF section which is not actually necessary for a DPF delete and even for remap unless you go into very high numbers.
Keeping the catalytic converter section keeps the amount of smoke lower. Also worn injectors contribute to the amount of smoke.
During summer you probably will not have any smoke.
Doing the glow plugs might also help.

Cat and dpf are two sections in same housing.