How smokey or otherwise is your diesel? - Page 2 - PeachParts Mercedes-Benz Forum

ROLLGUY · #16 01-22-2013, 04:34 PM

Quote:

Originally Posted by ah-kay

Hi Rich, I do not think Veggie or D#2 make a difference. I think the engine are all tired with many many K miles.

I have noticed a slight color blue smoke when running veg, but no smoke when running D2. That just may be my vehicles because of the blend I run.

Orv · #17 01-23-2013, 07:02 PM

Mine smokes until the turbo spools up, leaving a slightly embarrassing black cloud for the car behind me to drive through at stoplights. The problem is I had problems with the ALDA and had to remove it, so there's no off-boost fuel limiting. (I have a replacement but it needs to be shimmed, and I've been too busy fixing other stuff.) The over-fueling on light acceleration also tends to cause carbon to accumulate in the engine, so if I drive it slowly for a while and then floor it to get on the freeway, it smokes like a Peterbilt for a bit. "Rolling coal" as the rednecks like to say.

Practically no smoke at idle, though, even cold. When I accelerate from a stop with the engine cold, though, I do get a bit of misfiring and some blue smoke, which goes away when it starts to warm up. Haven't quite figured out why...I'm thinking maybe it's related to not having an ALDA, since that seems to affect the idle.

I don't like smoke...to me it represents fuel I paid for going to waste.

jay_bob · #18 01-23-2013, 07:32 PM

You think our cars smoke? You haven't seen smoke until you witness a 0 to 100 percent step load on a 2.5 MW genset. It has a 16 cyl engine, not sure of the displacement but the cylinders are like 5 gallon buckets.

We do the test with a resistive load bank, basically a giant fan cooled toaster on a trailer. The resistor is tapped not unlike the blower control on a 123. There are controls that let you apply the load in steps or all at once.

When the gen goes from idle to maximum power instantly it is a sight to behold.

The engine goes from chugga chugga to VRrrrrooooooom and you hear the turbos (yes turbos, there are usually 4) screaming as the engine tries to recover speed. And a beautiful plume of black smoke blasted skyward out the muffler.

The test is designed to prove the response of the genset controls in response to sudden load changes. It must maintain voltage (the alternator regulator) and the frequency (engine governor) within acceptable limits. We put a recording scope on the output to document the test. The voltage and frequency want to drop and as the controls react by adding more fuel and excitation, they have to be careful not to overshoot the mark.

100 to zero not as dramatic but that is the tough one for the controls, it is real easy to overshoot especially on voltage - too much is a Real Bad Thing.

Unfortunately I cannot make a movie the next time I am on site due to customer security rules.

Just another fun day at work...

Codifex Maximus · #19 01-24-2013, 01:06 AM

My 83 300D Turbo smokes like a freight train when I first start it then cleans up considerably.

My 84 300TD Wagon doesn't smoke at all even when I romp on it.

My 240D hasn't smoked in quite some time.