Dodge Cummins Diesel Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hey Guys,

New to the forum here. I just wanted to post this question, I'm sure it's quite easy to answer given all the experience of the collective here.

So I own an '07.5 2500 mega cab manual 6.7L truck. The dealer who had it before me had to do some work to it, most notably the guy who traded it in took his tuner with him so the truck wouldn't run. They ended up getting the truck tuned and stacked with 5 tunes, selectable by mounted dial. They also replaced the entire exhaust from turbo back, so it's pretty much a straight pipe with a muffler, nothing else. Airbox is stock, EGR is all deleted.

The highest tune is +180HP, and I run it on that tune all the time because it gets the best gas mileage, plus I drive pretty conservatively. Not that easy to hot-rod a manual truck lol, and I take extra precautions when towing for obvious reasons.

Anyway, the real reason for this post: reading smoke. I noticed two things about the truck in regards to smoke out the exhaust:

1. In the winter, the colder it is, the more white smoke I get just on start up. Is this something I should be worried about? Pretty much never see it when it's warm, I'm assuming it's leftover unburnt gas in the exhaust?

2. If I get AT ALL liberal with the throttle, maybe 40%+ I get black smoke out the exhaust for a moment. The more throttle, the more black smoke. At most it lasts maybe 1-2 seconds before clearing up. My best guess as to why this is happening is the stock air box can't provide the air to keep up with the amount of fuel being dumped in by the tune initially?

What do you guys think?

Thanks for the input!

- Mike
 

·
08 Cummins
Joined
·
2,119 Posts
Is it a puff of white smoke on start or is it steady white smoke until it warms up? If it's just a puffy, that is most likely just a product of the tuning. If it is a steady white smoke, I would say that's a sign something else is going on.

Black smoke on a box 180 hp tune, is nothing unusual. The tune is most likely calling for more fuel during the transition than you have air for until the turbo spools. Does the truck have a clean air filter? A dirty air filter could cause that but I would say that on a 180 hp tune a little black smoke is perfectly normal.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
It's definitely just a puff at the beginning. The colder it is, the bigger the puff.

The air filter should be relatively clean, though may be coming to the end of it's life. Last I checked that little push reset indicator it was maybe down to a quarter of life left. But the truck has smoked liked that since I replaced it after purchase. I figured if I really want to reduce the smoke and have more of that fuel used, I'd probably have to get a less restrictive intake?


Is it a puff of white smoke on start or is it steady white smoke until it warms up? If it's just a puffy, that is most likely just a product of the tuning. If it is a steady white smoke, I would say that's a sign something else is going on.

Black smoke on a box 180 hp tune, is nothing unusual. The tune is most likely calling for more fuel during the transition than you have air for until the turbo spools. Does the truck have a clean air filter? A dirty air filter could cause that but I would say that on a 180 hp tune a little black smoke is perfectly normal.
 

·
Registered
Joined
·
3,575 Posts
Cold air, white smoke = normal. Move along, nothing to see here! :)
 

·
Registered
Joined
·
3,575 Posts
But, the bigger issue is the smell; if you exhaust stops smelling like Diesel and takes on a sweeter flavor, likely you're burning coolant. You'll see this as a much whiter smoke. Then, if you smell something more funky, likely you're burning oil. I tend to go more by the smell of the exhaust than the color. I've BTDT and am now at 214k miles and $30k in after market hard parts.
 

·
Registered
Joined
·
7,102 Posts

·
Registered
Joined
·
3,575 Posts
Ohhhh, but it’s been fun hasn’t it.:blues:
Lets just say its been an ever learning experience! But, the truck is a beast now.. :grin2:
 
1 - 7 of 7 Posts
Top