Black Smoke Question...

[BrianW]

Gents,

I do really enjoy reading the great info here, but have not read it all, so please be gentle.

Anyhow, the other day I was pulling my boat home (on a trailer of course) and the wifey was right behind me. It's been snowing a bit up here in Alaska, so the roads are slick. The road up to our house has a short, but very steep incline, and sure enough, part way up the rear wheels started to slip on my '93 F250 with the factory turbo.

I already had the front hubs (obviously the front) locked in, and was prepared for this scenario. As soon as the rear wheels started slipping (and yes the rear limited slip diff still works) I quickly backed of the throttle, shifted into 4wd high, and then got right back into the throttle.

No problem, the truck went right on up the hill, and at the top, due to a sharp right turn, I did the opposite, I lifted off the throttle, shifted back to 2wd, to avoid binding the drivetrain as the traction was much better up there, and took the boat to the house.

The wife assembly told me there was a big 'puff' of black smoke while going up, which I tracked down to the time I shifted into 4wd. She said it was a BIG puff, but she gets excited easily (good for me.)

So I'm guessing the smoke was due to excessive fuel from getting off, then right back on the throttle so quickly. Does that make sense?

Could it be a matter of old worn injectors, squirting out too much raw fuel, or is there a more serious problem I should be looking into?

Thanks!

Quick pic of the boat...

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and a pic of the truck...

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[Diesel JD]

I think that would be normal. Ever seen what happens if you downshift climbing a hill in one of these trucks? Even with B100 biodiesel, it's still a lot of gray smoke, adn when I was burning #2 I could turn day into night under that scenario. A big puff is no big worry!

 

[LUCKY_LARUE60]

That is normal, remember when you step back into the pump you delever more fule and the engine dose not have a chance to burn all of it untill the rpm's come up. Even turbo'ed you have a lag and will get black smoke untill everything matches. You ought to see my dump truck smoke between shifts and hear the fuel rattle untill the turbo chatches up and then the smoke goes away on my L10 Cummins.

Jim

 

[BrianW]

Thanks for the words of wisdom!

I sort of like the noise and occasional smoke. It reminds me that there's a serious powerplant under there.

Not sure what the neighbors think.

 

[Agnem]

Welcome to the site. Beautiful country your in up there. Another consideration is that what she witnessed may have been a carbon detachment. That's my word for the phenomena that occurs when a big chuck of soot breaks loose in the exhaust pipe, crashes into a curve and then becomes atomized soot which appears as though somebody exploded a toner cartridge in a laser printer. I see this on occasion when going up a good hill at speed, constant engine RPM, and EGT's rising. All of a sudden a big chunk will blow out and it will look like I shifted gears when in fact there was no change in engine feel, sound, or RPM. I've been able to visually verify this by looking in one of my stacks, I can see where the soot which lines the interior walls has occasionally broken off leaving various shapes and sizes of soot lining depressions. I've also found chunks of same on the walls and floor of the garage when I first start up.

 

[Freight_Train]

Just wait till your doing the same thing at night and you see a spark or two go flying out the tail pipe.Now that will get your attention.Also,that is normal.Before mentioned Carbon Chip that got hot enough to ignite.