Hey guys. I own a 2003 5.9 Cummins with 377000kms. I just replaced my injectors and now when it starts a good size of black smoke comes out my exhaust and continues with a hazy smoke while idling. Seems to start, run and idle fine. The only aftermarket part is a 4" mbrp exhaust, no catalytic converter which I got installed only a couple months ago. I've only owned the truck for 6 months. It's my first diesel. Not too sure where to start.

Thanks for reading!

 

What size injectors? New or Reman? Does it smoke while driving?

 

They're 305 HP injectors. They came out of a truck with about 50000km. They were tested and are all 100% it doesn't appear to smoke while I'm driving.

 

I should add that my coolant and oil level have not changed at all

 

You are good- my truck starts with a puff with 100hp injectors and has a haze if your looking for it at idle. I wouldn't worry about it- seems normal for larger injectors. If you had excessive smoke driving or motor was running poorly it'd be a different story!

 

Cool! Thanks for the input! These diesels are unfamiliar territory for me! Haha.

 

If those are stock injectors and you have stock tuning, the injectors are bad. You should have NO smoke of any kind at startup if the injectors are quality. Used injectors are a bad idea no matter what some shop's testing determines, the testing on a bench is too subjective to rely on.

Even large performance nozzle injector should not haze or smoke at an idle, that is an indication of poor assembly or poor orifice formation.