Operators say the machine is “down on power.” That can be a protection limit, a fuel problem, or an engine that is genuinely breathing poorly. The smoke colour and the rpm under load separate them.
Work through this list
- Active derate codes and high engine temperature
- A packed air filter or a split intake hose
- Fuel filters, water, and low fuel pressure
- Boost that is below what that engine usually makes
- One cylinder that is cold, pointing at an injector
Black smoke with low boost is often air. White or pale smoke on start can be fuel or compression. Write down which one you see before you order parts.
A short video of the exhaust under load, plus the engine serial, is enough to start a useful parts conversation.