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  #31  
Old 02-15-2008, 01:51 PM
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Quote:
Originally Posted by doxland View Post
PE Haiges

These last comments about leaning are Gasoline engine thinking.
Diesels (if in an acceptable running condition) always run in overleaned or beyond full air. There is no excess fuel.

Leaning is Gasoline engine thinking and has no place in Diesel operations except that when they come to the excess fuel condition or poor atomized condition they may have combustion continuing on through the exhaust process and burn fuel while passing the exhaust valve.

Gasoline engines always used to run in an excess fuel condition so as to make combustion commencement reliable and to help control the exhaust temperatures.
There is a difference though, between simple black smoke and overfueling. Overfueling is done to produce as much power as possible by providing more fuel than there is air to burn with. What this does is ensures every bit of that air is used. Allthough in this case i wouldnt think this is that.. Sluggish performance would indicate so.
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  #32  
Old 02-15-2008, 03:13 PM
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Diesel engines work in a Diesel Cycle, which consists in heating air by adiabatic compression and later adding fuel that will be ignited by the heat inside the chamber. Considering this is a constant pressure cycle, in order to achieve that pressure in a cylinder that displaces an specific volume per cycle, you need to have all the air possible. This means diesel engine always intake all the air possible. What determines the power output of the combustion will always be the amount of fuel injected.

Gasoline engines work in a Otto Cycle, which is a constant volume cycle. This means that the power output will be determined by the volume of air/fuel mixture compressed by the piston.

Proof of this is that in Diesel engines, you control fuel delivery with the accelerator. There's no paddle in the intake, which means all the air volume possible enter the engine on every cycle. In gasoline engines, you have a paddle in the intake, which allows you to control the volume of air entering the engine through the accelerator.

Just a piece of knowledge, as simple as I can remember it...
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  #33  
Old 02-18-2008, 02:23 AM
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Paddle on the intake

MY 82 Datsun Diesel has the Bosch/Kiki IP. the intake has a carburator looking little thing that has a paddle inside, controled by the foot feed. this controls the amount of air injested. there are 2 vacuum lines from this to the back of the IP, which contain the governor. there is a leather diaphram that seperates the 2 sides of the gov. one vac. line on either side which pushes or pulls against the diaphram to control the fuel.
I know there are levers etc.. inside and more to it than just that.

There is also a bolt with a lock nut to add or increase fuel on the back of the IP.

This engine is naturally exasperated, no turbo.

I guess the boost line from the intake manifold to the ALDA does the same sort of thing on the MB. except with boost instead of vacuum.

Charlie
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  #34  
Old 02-18-2008, 05:29 AM
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charmalu,

U have a vacuum controlled Injection Pump (IP). I had a Perkins Diesel in a Fordson Major Diesel (built in England) Tractor engine that had that type of IP. There was no mechanical linkage to the IP.

Seems like my old 59 180D MD pushrod Diesel had that type of system too. It also had another flapper valve in the intake manifold that would close if the engine ran backward.

P E H
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  #35  
Old 02-18-2008, 10:48 AM
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The Alda does nothing directly to the boost, it modulates fuel flow relative to boost.

I know, more fuel will likely increase the boost indirectly, and then the ALDA will allow more fuel.
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  #36  
Old 02-18-2008, 02:41 PM
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Quote:
Originally Posted by babymog View Post
The Alda does nothing directly to the boost, it modulates fuel flow relative to boost.

I know, more fuel will likely increase the boost indirectly, and then the ALDA will allow more fuel.
it simply cuts the fuel going to the engine before boost comes up.
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Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.
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  #37  
Old 02-18-2008, 06:28 PM
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u need more air just turn up your turbo all the way and be sure to mash the pedal all the way as much as possible..
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  #38  
Old 02-19-2008, 01:32 AM
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Good discussion. Learning a lot.
I'm not a Diesel expert (yet) but I think one reason Diesels smoke when under load is there is a lag for the exhaust to spin the turbo faster and get the extra air into the cylinders. Just a thought.
So, I concur, there's unburnt fuel coming out the tailpipe. It could be as simple as the lighter fuel components have evaporated and left behind a lot of gunk and gum. I'd say change the oil and oil filter (it's a must do if it's been siting that long--transmission fluid and filter also a good idea) change the air filter, dump in a dose of fuel treatment/injector cleaner and go for a nice long ride.
Fill up with a fresh tank of Diesel fuel and a double dose of fuel treatment. Run it for a while then change the fuel filters.
If that takes care of it, great! If not, dig a little deeper.
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  #39  
Old 02-19-2008, 11:18 AM
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jamesNB,

Some of your post may have merit but changing the fuel filters when there is no power loss is ridiciulous.

The reason diesels smoke is because the mixture is too rich. Gasoline engines will also give off black smoke if the mixture is too rich. Ever have a stuck choke or bad carburator?

Ever see a tractor pull where the Diesel tractors pour out volumeinous amounts of black smoke? That's because the IPs are adjusted for a very rich mixture and maximum power.

P E H

P E H
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  #40  
Old 02-19-2008, 11:40 AM
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I must have the only MB in the world that does not bellow, belch, or blow huge clouds of black smoke. I never get black smoke, even at WOT...no smoke. Therefore, all YOUR MB's must be out of adjustment.

Black smoke = unburnt fuel....heck it even still smells like diesel. And every time I see it, I think....what a waste! Frankly, I don't understand the sense of pride some have in being able to produce these "big black clouds of smoke" when merging on the freeway. Why does wasteing fuel and spewing black smudge over other motorists seem fun or cool?? My rant for the day is now ended.
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  #41  
Old 02-19-2008, 11:44 AM
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You've got a turbo in good tune Mark. I sold M-B new when the turbos came out, they didn't smoke at WOT, big difference from the NA engines. They can be "tuned" to smoke, more power from more heat, some people choose that but tuned to original specs they will not.
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  #42  
Old 02-19-2008, 08:28 PM
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Quote:
Originally Posted by P.E.Haiges View Post
jamesNB,

Some of your post may have merit but changing the fuel filters when there is no power loss is ridiciulous.

P E H
Re-read my post. Maybe it's not clear but I'm not saying changing the filters will fix the problem. I'm saying change the filters because they will need it.
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