(b) determining whether it’s one or all cylinders, the next step is to determine why. White smoke means one or more fueled, but misfiring cylinders, and usually accompanies cold starts (in a warm engine it may indicate low compression). Black smoke is the sooty residue of partially burned (high HC’s) fuel, normally present during hard acceleration. Blue, blue-white, or white results from lube-oil combustion. (ON #170) BLACK or DARK GRAY SMOKE Symptom Probable cause Remedial action Smokes under load, especially at high and Injector pump timing Set timing. medium speed. Engine retarded. quieter than normal. Smokes load, especially at low and Injector pump timing Set timing. medium speed. Engine advanced. noisier than normal. Smokes load at all speeds, but most apparent at low and Weak cylinder Repair engine. medium speeds. Engine compression. may be difficult to start. Smokes under load, Clean / replace Restricted air especially at high air filter cleaner. speed. element. Smokes under load, Turbocharger Check boost noticeable loss of malfunction. pressure. power. Smokes under load, especially at high and Dirty injector, Clean/replace medium speeds. nozzle (s). injectors. Power may be down. Smokes load, especially at low and Clogged / restricted Clean/replace fuel medium speeds. Power fuel lines. lines. may be down. Puffs of black smoke, Repair/replace Sticking injectors. sometimes with blue or injectors.
(b) determining whether it’s one or all cylinders, the next step is to determine why. White smoke means one or more fueled, but misfiring cylinders, and usually accompanies cold starts (in a warm engine it may indicate low compression). Black smoke is the sooty residue of partially burned (high HC’s) fuel, normally present during hard acceleration. Blue, blue-white, or results from lube-oil combustion. (ON #170) BLACK or DARK GRAY SMOKE Symptom Probable cause Remedial action Smokes under load, especially at high and medium speed. Engine quieter than normal. Injector pump timing retarded. Set timing. Smokes load, especially at low and medium speed. Engine noisier than normal. Injector pump timing advanced. Set timing. Smokes load at all speeds, but most apparent at low and medium speeds. Engine may be difficult to start. Weak cylinder compression. Repair engine. Smokes under load, especially at high speed. Restricted air cleaner. Clean / replace air filter element. Smokes under load, noticeable loss of power. Turbocharger malfunction. Check boost pressure. Smokes under load, especially at high and medium speeds. Power may be down. Dirty injector, nozzle (s). Clean/replace injectors. Smokes load, especially at low and medium speeds. Power may be down. Clogged / restricted fuel lines. Clean/replace fuel lines. Puffs of black smoke, sometimes with blue or white Sticking injectors. Repair/replace injectors.
Completed%20ENGINES%20DO.docx