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  #31  
Old 06-29-2006, 11:08 PM
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Quote:
Originally Posted by Brian Carlton
..........somebody did..........sharp eye Jimmy.

Shows how much I have going on in my life.......
This thread is giving me tired-head, as I've never seen these adjustments done. I have to see something, I just can't picture it from described words......
Fascinating read, though.

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'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
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  #32  
Old 06-30-2006, 03:53 AM
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Well, this is going back and forth.....
I had just copied " The injection timing, determined by the wellling up method " to ask where you got that from.... then yall seem to be going to the drip method...now you are back to " noone seems to be praising the drip method"...

I only know of two methods shown in my set of Factory Shop Manuals concerning setting the IP for my 1980 240d... low pressure ( drip ) and high pressure ( requiring equipment I don't have )....

This ' welling up ' deal is a mystery to me. Where did you read about it ?
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  #33  
Old 06-30-2006, 07:50 AM
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Greg,
It is just looking at the drip from a different angle. I prefer the drip method myself.
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  #34  
Old 06-30-2006, 08:45 AM
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Since the FSM specifies that one is looking for one drop per second... the formation of drips by drops per unit of time is fairly specific and reproducible physics wise.. I do not understand how the well up method even hopes to get that specific with regards to flow rate.
The makers of the cars told how to use the little drip tube .... which I made myself from an old fuel line... Why do people not think they had good reasons for what they were suggesting ?
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  #35  
Old 06-30-2006, 09:00 AM
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My understanding is the well up test is not as good as the drip test. Since when you advance your pump from an indicated 6-7 degrees things get much worse it becomes interesting. Also that very rough idle had caught my attention much earlier. I wonder if it might be productive to read and post the various milli volt readings from the cylinders. I am starting to wonder if someone might have played with the element adjustments either accidently or on purpose not knowing what they were doing. There are recorded instances of past owners getting the number one element off by trying to do the timing improperly.. They removed and reinstalled the part with two nuts. Or perhaps all it takes is too much force applied when hooking up the injector line again. If there is a vast difference in milli volt readings between cylinder 1 and the others, say 3 milli volts,with a few other minumin tests to verify the accuracy of the reading you have it. Also you will probably be able to correct it unless they removed the shims underneath. Not too likely in my opinion. I really would stop at this point and read the heat in each cylinder with the milli volt method. Costs nothing and may reveal a lot. Something odd is going on here it seems. Logic would seem to indicate since the chain was not installed properly perhaps someone fooled around trying to get the engine to run better. I hope not but it is detectable with the reading of the glow plugs and a few simple tests if the glow plug voltages are off value. If the glow plug voltages are pretty uniform in comparison to each other you have cleared the pump itself pretty well. I suspect your pump is not going to make the test but hope I am wrong. As for a drip test tool. Just get an injector line and fitting from a junker and make your own. I am not sure if the well up test can be way off but there has been some information posted that it can be negatively affected by the delivery valve. To what extent I am not aware. Common sense would almost say certainly not to the extent you are seeing but I may be wrong about even that. In the old days a thread like this could go on and on without being resolved. It is no longer required as we now know how to eliminate things lets say in a more scientific manner. The underlying question is will the milli volt system become a generally used tool? I personally know of no other system other than substitution and guessing for these old indirect non computor diesels. As for timing by ear? Not a particularily good ideal if what I suspect is wrong. You will never have good fuel milage for starters plus really good cold starts will be affected to some extent next winter. Or just could be better. My best guess is cylinders 2,3, and four are advanced with number one displaying a retarded effect..That why the car runs fast for a 240d with a poor idle. Your millivolt readings would reflect that by a lower voltage on #1 cylinder than the others. Sorry about the long rambling post...

Last edited by barry123400; 06-30-2006 at 09:52 AM.
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  #36  
Old 06-30-2006, 09:29 AM
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The welling up method is documented on this site in a few threads and there is actualy a writeup on it on another site.

http://users.vnet.net/w123d/w123d/injectiontiming.htm

I dont know if Im reading that method correctly since the empirical evidence is that the pump is 1 tooth off but the welling up method says it isnt. So, I guess a milivolt method and some drip tube action are in the works.

For the drip can I just use a bent piece of regular rubber fuel line or do i need the hard injection line thats been cut and bent?

For the milivolt method I will try that tonight. The only thought I had with regards to element movement was that I would have expected the timing to work correctly but still have the shake if the elements were moved. However, with the timing set to what look slike correct, its blows black smoke and acts like its VERY advanced.

Its a mystery!!!
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  #37  
Old 06-30-2006, 09:40 AM
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http://users.vnet.net/w123d/w123d/injectiontiming.htm

Who ARE those people ?
Did they manufacture millions of Mercedes Benz ?
Did they have million dollar R and D departments which decided the million dollar Mercedes designers got it wrong ?

How can one expect EYEBALLING the WELLING UP can come close to matching seeing one drop at a time....and timing those drops ?

I also think you need to put a fuel can a few feet above the pump in order to have the steady pressure for the time it takes to move the pump. Using the hand pump only provides a decreasing pressure as you open up and try to adjust the position of the pump body....

What would you attach the rubber line to to use it instead of the metal bent tube ? and in curving it one would have to be sure not to crimp it doing such a sharp bend....
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  #38  
Old 06-30-2006, 09:49 AM
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So I guess its safe to assume that your not a fan of the welling up method leather! Lots of people on this board have used it so it cant be total snake oil. But I will agree that its not working well for me.

My question about the rubber hose is simply can I fit a piece of rubber hose over the #1 element and use that to check the drip. Is the calibration of 1 drop per second related to the diamter of the drip tube. If it is than the rubber hose wont work. What Im looking for here is a method to get me close for now. For perfect dial in timing yes, drip tube is the factory way. At this point I just need to narrow down the field to pump is 1 tooth off or pump is fine and look somewher else.
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  #39  
Old 06-30-2006, 10:13 AM
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No, the drip method is not dependant on the size of the tube... it is dependant on the PRESSURE and the size of the opening of the valve.

If you have ever taken a chemistry course in which you had a lab... making droplets is one of the main methods of measuring stuff... you put a bunch of stuff into the tube ( pipette ?) above the flask you are dealing with... and drip stuff into it... either counting the drips.. or measureing the height in the dripper unit before and after whatever reaction you are looking for... often using litmus papers for the determination..
If you are using basically the same fluid... at reasonably the same temperatures... the size of the drops... which is another way of saying the increment size ... is very stable... so once you have the parameters in the instructions as to drops per second... if you get that you will be very close to what you need ( keep in mind the pressure part of the variable ..thus the suggestion about the fuel can to provide steady pressure ).
I do not see that EYEBALLING the WELLING up can come anywhere close to that sort of specificity.
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  #40  
Old 06-30-2006, 10:14 AM
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I will try to clarify my position. It does not matter if you time #1 to perfection if 2,3,and 4 pump elements are greatly advanced in comparison to it. The milli volt reading will verify or condem this. He is running with good power and black smoke. All the signs are there. I still hope there is a good chance it is only number one pump element that is off. The other simple tests are to eliminate things like the glow plug calabrations by swapping it with a neighbour to verify results. Should hopefully be easy to correct. On the otherhand if nothing else it will pretty well clear the actual pump. The milli volt system is easily sensitive enough for that. Just remember to ground your meter lead to the head or your readings will float around so much you will not get usable results. If by any chance my guess proves accurate please contact me on this site before any adjustment takes place as people have showed a tendency not to do all the preliminary steps to make sure the results are really accurate. We also still need all kinds of feedback.

Last edited by barry123400; 06-30-2006 at 10:30 AM.
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  #41  
Old 06-30-2006, 10:17 AM
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" Lots of people on this board have used it so it cant be total snake oil."

Lots of variables there ..... people can get lucky, these engines are fairly forgiving ( although I can understand you not feeling that way right now ) ...and you have no empirical tests on the running condition of those engines people who say they used that with success....
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  #42  
Old 06-30-2006, 10:28 AM
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Leather, the method of measuring drips you are talking about is called titration and with the number of years in the science field I have I know it all too well. As you said, the determining factor is pressure. The pressue is directly proportional to the diameter. So, what Im concerned about is a rubber hose that has a larger internal diameter than the standard drip tube will have a lower pressue. Therefore, will the timing of the drips need to be modified based on an unknown pressure variable from the tube.
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  #43  
Old 06-30-2006, 10:36 AM
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I was not sure how to spell it without looking it up... so I did not use it...

You are thinking about more volumn than this is going to give you.. thus it is the size of the valve opening and the pressure which will determine your flow...
the tube is just the apparatus for making Drips which you can see...

It is the pressure behind the Bottleneck ( the valve ) which is important.. you have no measureable friction after the valve to affect the flow rate.

Last edited by leathermang; 06-30-2006 at 10:42 AM.
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  #44  
Old 06-30-2006, 10:43 AM
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The pressure takes place inside the pump. Once out it is subject to atmospheric pressure as a constant. The only varience I can see would be the larger the tube the more input required to cause the drip because of surface tension on the larger tube diameter at the full level. This is subject to discussion as well. But talk of splitting hairs. I believe as well not to be argumentative that the drip method has some things going for it that are perhaps important over the well up method. On the otherhand the well up method gives one an opportunity to dip their wick. Perhaps it boils down to some guys want to dip their wick while others do not. I wish I knew what I was talking about.

Last edited by barry123400; 06-30-2006 at 10:50 AM.
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  #45  
Old 06-30-2006, 11:02 AM
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"I wish I knew what I was talking about."
I wish you did too

"The pressure takes place inside the pump. Once out it is subject to atmospheric pressure as a constant. The only varience I can see would be the larger the tube the more input required to cause the drip because of surface tension on the larger tube diameter at the full level."

True but completely unmeasurable ...and once the flow across the top of the obstruction ( the top of the bent tube ) is breached the wetted path will completely negate that... and anyway how much of a difference in interior size of these tubes are we talking about... and since we are dealing with fuel maybe we should throw in vapor pressure causing restriction also !

"This is subject to discussion as well. But talk of splitting hairs."
I am trying to talk him into accepting the metal tube and going on with this..

"I believe as well not to be argumentative that the drip method has some things going for it that are perhaps important over the well up method."

AW come on, throw caution to the wind and say it... it provides ACCURACY the other method does not !

On the otherhand the well up method gives one an opportunity to dip their wick. Perhaps it boils down to that some guys want to dip their wick while others do not. I wish I knew what I was talking about."

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