Different types of smoke for diesel cars. - PeachParts Mercedes-Benz Forum

ericnguyen · #1 04-01-2003, 07:34 PM

Dear friends:

Could someone tell me how many types of smoke (while, black, blue etc...) there are for a troublesome DIESEL engine?

Please also give a brief description of what may be wrong depending on the smoke type.

Thank you very much.

Eric

joe p · #2 04-02-2003, 07:39 AM

Blue = pump timing or just wore out. (even a bad turbo will cause a little bit of blue)

Black = overfuel, either normal under boost or volume/rack setting wrong.

Grey= pump timing, chain stretch, bad nozzles or several other little things.

All this is dependant on engine temp, overall running (skips, fuel knock and so on), mileage and so on.

Just as a example, my cummins smokes blue cold, black as sin under boost and on long idle will blow white on accel. None of this is a problem, just the nature of the beast in its current state of tune (250hp750torque)

Joe

PaulH · #3 04-03-2003, 10:40 PM

Black smoke can also be from bad nozzles which aren't spraying (atomizing) the fuel enough, so all the fuel doesn't get burned. If the engine smokes a lot of black smoke at start up after an overnight sitting, then the injectors are probably "leaking down", i.e., leaking raw fuel into the cylinder(s) during the hours of shut down. Usually white smoke indicates water vapor in the exhaust (Poss. head gasket leak or cracked head). Joe brings up a good point, though. If the smoke is just a short time event, you are probably OK. And, finally, bad fuel can cause a lot of smoke. The next time you get fuel, try a different station or brand of fuel.