that means your running rich correct?
Yes and no. The engine may still be running quite lean if you were to measure the air/fuel mixture by weight. There really is no rich/lean in diesel combustion, it is variable depending on the engines output at any given time and is generally very lean. Diesels have rather poor air utilization rates compared to homogeneous charge engines (gassers). In a diesel the fuel/air mixture must form as the fuel is injected. This all must happen in a tiny fraction of a second. All of the air is often not able to combine with all of the fuel before the exhaust valve opens. The result of this is black smoke, even with a considerable amount of excess air.
Black smoke does mean the fuel is only being partially burned, which can be a symptom insufficient excess air, worn injector nozzles, low compression or low boost on turbocharged diesels.
If you got the all the smoke by adjusting the pump, then chances are its just excess fuel. Diesels tend to make their best power just as the exhaust begins to darken. I've tested this theory on numerous diesel standby generators using load testing equipment. Additional fuel beyond the point of smoking adds little to the power and can actually reduce the power if you get really carried away. It can be harmfull to the engine as well. If excess fuel is injected it may still be burning as it exits the cylinder, where it can potentially damage exhaust valves and turbocharger turbine blades. The excess soot will also contaminate the engine oil more quickly.
Topic: If you have black smoke.... (Read 2585 times)
