Another good tip and enlightenment came from Coldwar via pm this morning.

Has Mercedes been holding out on us? Apparently he is under the impression that they have a special truss tool to hold and adjust the pump hopefully dynamically on 123s and he thinks he can duplicate it at home.

There goes the tap and wood block routine or pried pump.
Never really liked it anyways.
What if someone got overly agressive?

Why can I not visualize these things in advance?
Describing what I would do was a nightmare in comparison.
I will have a look under my hood as it has got to be a pretty simple tool or if he has a picture or drawing of it that may make it even easier.
It will not be rocket science either way.

Thanks Coldwar and when the price of vegetable oil starts it's upward spiral I have told the wife to blame you.

.

Yeah I told him about it. Its mentioned in the FSM and even gives its part number.

http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/Engine/617/07_1-114.pdf

I have a thread at my site about fabricatining one for yourself in its early stages.

lot of flexibility in design...I don't like the original as it uses two head bolts to attach to the block. Id rather pick a different anchor point and make something simular in function.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

There's an even better picture of it right here at Mercedesshop under Special Tools- Index #617-0721
Dave

I've been closely following this thread but I'm even more new to the Forum than you and I was not able to find what you referred to as having index "617-0721". What tha hay!
Can you give us novices a html link?
Sam

'Fraid not - the catalog loads inside a single html page so you can't post a direct link very readily. BUT if you look at the menu at the top of the page, you'll see a tab for "Special Tools." Click on that, then click on the CONTENTS link and go to page 28. Its the last entry on the page.

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Tjohn

82 300 SD
77 450 SL (gone)

Design ideals are welcome for the adjustment jig.

The Mercedes service part is for adjusting injector pump timing with a running engine.

So far people like bonehead, dave and myself I believe are not really happy about having to remove two head bolts and use them for the mount like the factory one does.

Bonehead has been looking at home fabrication of one but his ideals are not set in stone either I believe.
I had a quick look but the first substitute I visualized almost seemed like a rube Golberg ideal unless a plate is made to sit over the head bolts and a method is designed to clamp or secure it there.
Should work if carefully though out.

Perhaps someone will have a better ideal.
Have a look at the factory part.
Then take a look at your engine bay.
Consider it a contest.
The winner gets a hard time.
Plus the questionable distinction of being caught up in the mess.
Also am I ever going to get it if all this does not a work out.

That thread will be far more interesting than anything so far.
In fact it should set record posts as all the current record holder did was install his pump 180 degrees out.
I guess I could leave the country.
Since I live in Canada perhaps that is already accomplished.
Anyways lets hear your ideals.
No I do not need a new therapist.
The present one is enough although getting no results apparently. .

.

For a contest, we'll all have to go Secret Squirrel, right? When device is successfully completed, post a pic and may the best man win!
(Me, I have no machining tools or skills whatsoever- it's all gonna have to fasten together from the junk bin. Should be interesting.)

and that's a sure sign that we have stalled out our brains... so let this "nubie" ask a question or two and maybe get us back on a more productive track:

Q1 - Barry, was there a thread prior to the present [" Setting pump primary timing..." ]... another thread on this same subject?

Q2 - Barry, do I understand you correctly that to "average" the milivoltage of the engine's glow plugs you merely wire all of them together [parallel]?

Q3 - Barry, have you played around with the values for the capacitor and resister you used to stabilize your meter's readings?

Regarding Q2, I have found that I can use " banana plugs " to easily connect to all three of my M-B car's parallel glow plug system via the "female" plug on the line that plugs into the GP relays. The full-size " banana plug " used on my digital VOM connects very effectively into these multi-conductor inline harness plugs.

Sorry Barry, I'll read your threads no matter how stung out your writing might strike me ! Are you really seeing a "shrink" ?

Thanks Dave [ColdWar], I finally found the M-B "Tool" thingy you referenced. I'm still exploring the "Ns-&-Outs" of the MercedesShop.Com WebSite!
Regards,

Sam... a serious kind of guy

Alright I finally did it!

I didnt have time during the week (work) to really put time into adjusting my fuel elements, but after a good 3 hours today I finally got it pretty well done. Unfortunatley I did not get the two electrical parts you had mentioned to do this job but feel the two elements are within + or - .3 mV compared to the 3 reference glowplugs.

The way i did it was to disconnect all 5 glowplug wires and then I attached loose alligator clips to each glow plug and then clipped the ground to the front strut mount nut on the right side of the engine bay. That way I could quickly measure readings from one glow plug to the next. i made sure to write down the readings after each adjustment just to keep track of patterns.

Took me a while because every adjustment created diffferences in the other readings of the other glowplugs. For instance with every adjustment of the #1 to raise the mV, this would make the mV readings on my #2 go down, but not vice-versa. Yet, raising the mV on the #2 glow plug would make the #3,#4, & #5 (references) go down. Very frustrating! Plus initially I had the nuts holding the fuel element too loose and thus my adjustments were not small enough. As I got closer to my target I tightened the nuts slightly. On top of which I noticed that with every adjustment you had to let the injection settle for a good 15-20 seconds to get a moderatley acurate reading.

I ended up with close to about 10.8-10.9 on each glow plug. After I get the car warmed up tomorrow, im gonna measure it again to make sure they are still relativeley even across the board. If so Ill go ahead and do the IP timing to the engine as well as adjust my valves and insert my new rack dampener pin. Then i will go back and measure the glow plugs again in hopes of seeing raised mV's, so I can guage my efforts.

As of right now, a deffinite improvement in the idling...much less shaking and noise. Havent really put it on the highway yet but I will tomorrow. Just got a new full tank of fuel, so I will report on efficiency as soon as I can.

Thanks so much Barry!

P.S. get some 8mm nuts, I lost a few continously (this was my third effort) removing and replacing them from the GP's.

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1983 300SD White with Grey interior

Jman300sd.
My hat is off to you to even get that close without the use of the resistor and capacitor.
Without them it is very hard to average voltage.
In fact twice as hard as doing the primary pump timing.

It was quite hard without the stabilization as well so can only imagine what you went through.
I would not like to do it without the modification.
I think when you incorporate them into your circuit you will still be able to improve results.
0.3 miilivolts strikes me as still quite a lot if you read that high a difference but as you are aware with the meter hunting it is hard perhaps to do better.

I cannot relate it to degrees but still feel it significant.
Plus since you have done it the hard way the next time with the modification will be like a walk in the park.
Plus more accurate by far I believe.
I myself would not touch the primary pump timing until a few small tests are completed.
That we can discuss later.

What is disturbing me is with the exception of a few we are not getting enough proper feedback yet.
Until we do it will be hard to move this forward.
At present that is understandable.

I also want to be cautious before making some assumptions as well.
Your driveability and fuel mileage might give some indication of how close you are.
Anyways thanks a lot for reporting back.
Plus it is of benefit to other members to report until it is perfect.

Somehow you approached this on faith so to speak.
Remember to only work in your case #1 element to numbers 3,4,& 5 until they are identical.
Only then go to number 2 and work it till identical to 3,4,&5.
Then they all should be identical voltage across the engine.

My thought still is for you to get the capacitor and resistor.
Good going so far as you are the first test horse and are going to completely pull this off I suspect.
Not quite there yet.
But getting close.
Your technique tips are valuable as well.

The finish mv is irrelevant in my opinion it just indicates the heat generated and will vary with idle speed.
Perhaps you mean it will indicate if your tune up is beneficial.
That area is perhaps in the future.
I personally thank you for taking the effort so far though.

.

Barry, you mention i should not touch the primary pump timing. Why exactly is this? You think i should get my readings closer before i attempt this.

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1983 300SD White with Grey interior

Sam, there was an earlier thread where I basically speculated on potential as a valid service tool.
Plus helped or tried to on two people with trouble.
The first gentleman had an obvious well advanced element.
I did not like the ideal of doing it by ear at my suggestion but it worked.
That started me thinking.

The second gentleman did it by ear and voltage comparison but discounted it as he said he thought the result was no better than by ear but that was wrong as he went back and forth till he got identical voltage.
His engine than ran very well.

Although I also fully agree with a hunting meter it would be very hard and hardly seem worth the effort to verify.
He also did not report the hunting meter as well and I was unaware of that effect until I saw it myself and the recent gentleman mentioned it.
Yes all the glow plugs linked or in parallel will provide an engine average.
I personally would like to read them all individually to ascertain that a problem did not exist that would tilt the average excessively prior to linking them all up though.

Say a glow plug was found in the group that was substantially lower or higher than the other four.
That should be investigated as why that cylinder is generating less or more heat.
If it was found say you had one cylinder of low compression and could not rectify it then I would use the other four plugs alone to establish an average.
Could be as easy as a tight valve for example though.
As for the components used with the voltmeter.
No they are not critical at all I believe other than I would want to see the condenser above 2500 microfarad and the resistor at probably 1k or better.

No harm to experiment but I got rock solid last digit readings with my values.
The addition of this is really important.
If you find the peak voltage has a plateau with a little width I would stay at the leading edge of it when you enter it.
That is primarily as we have no indication of how many degrees one tenth of a Milli volt represents yet.
If it turns out to be one or less it will replace all other systems.

As refinements are made we may have to move to a meter that reads 100ths of a Milli volt at some point in the future but at present 10ths of a Milli volt are OK.
I do not have at present and in past a therapist but who can tell the future?
I was speculating about the future perhaps as there is far more to be investigated with this procedure than meets the eye.

We have not even scratched the surface yet and to be hung up a little with so far to go is frustrating of course.
There will have to be a complete guidance manual written at some point as I visualize the uses as possibly extensive.
The last gentleman for instance may have had a really hard time as there is no general guide in existence yet.
Of course to try to expand the applications at this point would only result in bad feedback if not applied properly by a user.
It will have to move pretty slowly so this does not occur.

I do not have the time right now to really do this thing justice or disprove it.
It deserves better.

.

Jman300sd, you have already performed a very difficult task probably well with that hunting meter.

As soon as you get the components to build a voltage stabilizing device it will change everything.
The best pump timing is going to depend on that stability as well.

Your first statement about making sure they are all pretty well exactly the same still carries a lot of weight.
Of course any slight variance on 3,4,and five as individuals will have to be left alone if it exists.

There will have to be a set of protocols worked out at some point.
When you get your meter stabilized I would like to know the reading of voltage on each one of them individually.

At present it is starting to look like you advance your pump to the leading edge of the highest value obtained when reading the voltage.
As I have stated there is no risk if you pin punch mark the pump prior to adjusting as you can always then go back to your mark.

Also am waiting to see who can make or design a pump holder/ adjuster jig to simplify adjustment of the pump with engine running.
Am also starting to concentrate on how much advance is too much.
The last thing I want is pumps over advanced.
This is going to take some thought.

A gentleman set his by piezo electric pulse sensor a full eight degrees over factory setting the other day.
My suspicion is he may be too far advanced.
I am looking for a positive system to indicate that simply.
The old standards of less pre detonation may be flawed.
I now suspect top possible mpg for the type might be the test standard.

If you are too advanced mileage will be less than optimum.
There is a lot of work to do here.
It will take time.

.

I think for now what I have done will suffice in the operation of my car for a while. At some point though I would like to put new injector nozzles and at that point these mV adjustments might be even more relevant. But, I got a long list of things to do before then. I will provide fuel efficiency info as soon as I can.

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1983 300SD White with Grey interior

Jman300d, good ideal as it also provides a chance to reflect on things.
You are right as a term of driving plus indicated mileage etc will give you some indication if all is well.

A little time will add refinements to procedures and that may help as well. Just keep following this thread.
Pretty soon I am going to start doing Mercedes diesel pump to engine timing.
System worked out well so far on Volkswagens.

.