Hi,
do you say that the unplugged glow plugs will give a mV signal depending on "energy" of each cylinder?
Can a physical difference in condition of the cylinders (slightly different compresssion) be compensated by the adjustment of the individual fuel valve?
On the bench the deliveries are set all the same.
Interesting.

Tom

I was the other individual that messed with the element holders because they were leaking. Except I did it on my #1 and #2 elements on a 5 cylinder. Do you think this same operation (reading the mv on the glow plugs and adjusting accordingly) might help me with my situation. If you recall my problem is that my engine kicks and sputters smoke like hell upon start up for a good two minutes until it smooths out to a nice idle at 700 rpm. Once fully warmed up there seems to be no "knocking" but then idles at about 900-1000 rpms. Id really like to at least attempt to resolve this problem without having to remove the injection pump.

__________________
1983 300SD White with Grey interior

I don't think that Barry implied that low compression can be compensated for by adjusting fuel delivery timing. I think that he is implying that the fuel delivery elements may wear differently with respect to one another and therefore need adjustment. They are set at specific intervals on the bench, and that is how they should remain.
Using glow plug output voltage is certainly a good way to test the timing. It has been suggested for use in setting the initial timing, though not used extensively. I think that it would come in particularly handy for those using wvo and using higher pop pressures. Theoretically, this would set an optimal timing for those specific circumstances.

__________________
For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel

The simple answer is no I believe unfortunatly. Although being a dynamic procceedure things will be though out that can perhaps be implemented that were never perhaps done before. But even that at this point is a somewhat shakey statement. It's too early unless someone has published a book perhaps.There never was intent in original pump design to adjust pump in any fashion to correct for block difficulties such as wear and tear resulting in general uneven compression. Potentially it might be possible to smooth the idle a little but at an overall power loss . Unless the pump is reallly off of course. At this moment cannot think of anyone interested in doing that with the present limited knowledge. Thanks for posting as people are going to come up with many questions it is expected and unfortunatly it will take some time to examine this properly but applications just might come into general use yet. I suspect it is going to be the preffered method for me eventually but a lot of things have to be sorted out first. Wade I will try to duck out for awhile as it is your thread and hope you get all the answers you are looking for or at least food for thought and discussion. Also there are tests to determine if indeed this posters rough idle is caused by the compression itself or injection pump or injector wear over the years as well I believe. This was not available to home mechanics like myself before. Is still not quite yet until some things are worked out but think it's going to fly after awhile. This is going to sound stupid but you have checked your valve clearances in the last 20 k or so the car has gone as this will also cause a rough idle. Or make an existing condition worse. Perhaps a poor rack bolt? Injector condition? Also you did not post the differences in cylinder compression your engine now has so that limits things a little. Beyond a certain differential of cylinder compression it is never going to idle correctly but checking out other things and correcting them might lessen the effect or indeed cure the problem. It is still a good and harmless thing to check the glow plug output voltage even right now to aid in diagnostics to some extent of some problems . What you are basically duplicating is the same as reading the exhaust stack temperature on a large diesels individual exhaust headers with a thermal scanner But I think the glow plug reading is much more sophisticated on smaller indirect diesels. Anyways do not touch the nuts on the pump fittings until you absolutly understand what you are doing. Plus the need is really there and proved. Also most importantly it is proved that this approach is adaquate to the need as that has in no way been proven yet to my existing knowledge but again I lead a sheltered life to some extent. Too many unknowns. As information is posted this may change but for now consider those pump adjustments off limits. I personally want to not see anyone land up worse than when they started. That is an absolute and cannot be stressed enough. To be fairer at this point I do visulise a major improvement can be made once all other possibilities are eliminated and we really develop this approach to restoring injector pump sequential timing that has gone off to some extent with aging and wear that is the real underlying problem. Hopefully we will be able to fine tune the pumps back to new status in this function. I would take a guess it will take less than a year to work out all the possibilities and pitfalls or even if it is practical. Plus following a proceedure that takes all other possibilities and probabilities out of the picture when resetting the calibration. Again so much is going to depend on the mathamatical degree of movement versus voltage relationship knowledge and for this I may have to dig in myself with a little more complicated equipment unless somebody else wants to nail it down by whatever method they choose and prove it of course. Wades experience has already partially indicated the path to be checked out. It is just too early to attempt to sequentially retime the pump until it is proven practical by this method. Again too much information and restressing but what to leave out? Thanks Wade.

FWIK, the elements adjustment give the quantity of fuel for each cylinder.
How can the timing be adjusted by the fuel delivery valves?
To fine adjust my car I read the mV's of each glow plug and bring them to the same value by playing with the elements.
My IP should be perfect (almost new).
So adjusting the elements according the mV will result in perfect balanced fuel flows?
or
will result in different fuel flows depening on the cylinder conditions to achieve balanced out put of the cylinders?

Barry,
Your posts would be a lot easier to read if you would use some punctuation once in a while. Like starting new paragraphs for instance.

Danny

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1984 300SD Turbo Diesel 150,000 miles

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My hat's off to both Wade and Barry for this excellent thread. I think that we should still avoid messing around with the fuel elements, but the troubleshooting value of this thread is great.

I'm going to check the mv output of my glow plugs first chance. If for no other reason, to give me a base line for future reference.

Cheers,
Wes

morning guys,....I think that something has to be stated here
DO NOT,EVER EVER, LOOSEN THESE NUTS OR PLAY WITH THE POSITION OF THE HOLDERS.
Like Barry said,we will need to gather a lot more info on what exactly you are changing and by how much. Up until now,most people have said that if you even look at these nuts, you might as well burn your car and call the insurance company. Like i said before,i either got very lucky.or this procedure proved that you can attempt to adjust these elements. but once again let it be known loud and clear "I had virtually nothing to lose" My car was pinging so bad,that i was not even going to drive it anymore until i fixed it.
I also had the benefit of knowing that "I" was the one that created the problem,car ran just fine before i touched the valve holder. I also knew that all of following were set properly and working well: glow plugs and GP system-
IP/engine timing was right on-all injectors tested and working well-valves properly adjusted, good compression and valve timing adjusted to compensate for chain stretch.
I think that if your car doesn't start well,but lets say runs fine once warmed up,until you are sure that all of the above items are checked,you would be opening up a nasty can of worms by starting with trying to fine tune the delivery valve holders. For example,my car actually started fine,even when very cold, just a slight miss on #4 until it was warm,although i had to adjust my idle way up to keep it running,even when it was warmed up. But my major issue was a big power loss and an excessive amount of pinging/injector knock at almost all rpms with engine under load.
In theory its alot like the basic IP timing itself,once its set you should really never need to touch it again.But sometimes as pumps/injectors and engines wear,factory or bench settings that were intended for new engines do not work as well on more tired engines. IE...i have had other diesels that ran much better overall at a pump timing of lets say 28BTDC versus a factory spec of 24BTDC. Of course keeping in mind that basic ip timing is a lot easier
to fix or change back,then the miss tuning of the elements.
Also one last point that helped me, I only had one cyl that was out of whack, I cant imagine trying to ear or hand tune all 4 or 5 cylinders without removing the pump and having it calibrated.
I guess in closing the overall point is that it is possible to tune the delivery valves if these nuts have been loosened and the holder twisted either left or right,without destroying your car.

__________________
1980 mercedes euro 300D 232000 miles(died,now parts car)
2004 2500 ram cummins diesel
1980 harley shovelhead
1988 anniversery corvette zr1(engine)
1978 240D 4spd 240000 miles (new benz toy)
1946 Cessna 140, Continental 0-200

using the glowplugs as pyrometers to measure cylinder output is certainly an interesting idea.but you maybe chasing your tail if your using this method to calibrate your injection pump.consider all the variables that can affect the heat output of a particular cylinder,sleeve wear,piston rings,valve wear and timing,injection quality and quantity.my local injection shop has quoted $120 for a pump and injector calibration check.the test bench there can measure very accurately the timing and output of each pump element thru a wide range of rpm.a possible DIY workaround.attach a valve timing guide to the front of the crank pulley and using the drip method measure the start of injection in degrees btdc for each or selected cylinders.make sure "1 is set with the basic pump timing then adjust any deviant cylinders by rotating the pump element

Great wade the warning is loud and clear for now. As for the gentleman that moved his two elements. If it caused the problem then he should restore the pump to what it was prior to the disturbing. But cannot remember why he moved his elements timing in the first place. The smoking may be caused by late injection and marginal burn as injection may be taking place at lower compression point of cylinder than design intent. Incomplete burn is what I am thinking. if he again did not have the smoking prior to moving the assemblies. Anyways unfortunatley he appears to be in a position he has to do something. Another case of nothing to loose. May not eliminate his previous problem whatever it was though but just might get him back to where he was. Wish I had that mechanical degree per mv calculation worked out as we could start to talk about how close he can get to design intent. If he is pretty sure he has messed up the sequential timing it is prefferable to match one and twos voltage output to three and fours output to get the sequential timing as close as he can. If he adjusts voltage to higher than the three and four he is timing for the engine rather than the pump that I believe is his present priority. The old problem will still be there waiting for him . I have really given this some though in last several months and like yourself he has nothing but upside as what else can he presently do other than change the pump or off to the pump shop. Even his adjustments will not stop pump shop from putting it back on if it eventually has to go there. With the present level of knowledge we have to agree this is for anybody that has nothing to loose basically by doing it. At present am almost fixated on that by the way. Again just my opinions . He becomes number four where I believe a major improvement is possible with nothing to loose. Any comments?

Michael, I agree. would be much better to remove pump and get it bench tested. obviously would be more accurate.and there are too many variables associated with each cylinder to use the milli-volt system if you are comparing cylinder to cylinder.
The purpose of the thread was not to invite people to go ahead and fine tune the elements just because. But rather,given a last ditch effort,with a known poorly adjusted element,you can use this method to crank out the highest mv reading to increase the heat (energy) and ultimately the efficiency
of that particular cylinder.
Also, in my case you would not have needed the volt meter,there was such a dramatic increase in running efficiency that you could have easily done it with just eyes and ears. Not the best way to go agreed,but it sure fixed the problem with my motor,i am sure that a professional given the proper tools and know how, would get it much better still.
By the way, that is a very encouraging price quote for a pump re cal,had i known it was that cheap its probably the way i would have gone,then at least you know its set right. BUT HEY!!! what fun would that be?

__________________
1980 mercedes euro 300D 232000 miles(died,now parts car)
2004 2500 ram cummins diesel
1980 harley shovelhead
1988 anniversery corvette zr1(engine)
1978 240D 4spd 240000 miles (new benz toy)
1946 Cessna 140, Continental 0-200

I think this is the most valuable thread I've read so far this year, almost missed it. I'm going to try to monitor the output of my plugs and see what I can learn. I'd also like to see how linear the mV response of the glowplugs is WRT temperature. Nice work, guys!

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Michael, That was an approach I was going to add to wades initial list but on reflection was not really happy with a few things. At this point what is being done is experimental to say the least but does not compound the problem if otherwise the pump is on the way to a shop otherwise. We desperatly need a mechanical degree ratio per .2 mv to estimate what is really possible. On an engine in lousy mechanical shape you would just have to time every element to the highest possible reading no matter what it was and afterwards go back and retime the pump to the engine. This ideal bears examination as well and certainly cannot be considered until Mechanical degrees per mv are really known. It does not really matter then if cylinder pressure is off or rings worn or whatever since we are still timing for the hottest combustion point in that cylinder. It should occur at 180 deegrees after the last one fired. I suspect if it is firing at all it would still be useful. That alone should give an accurate 90 degree point to each element in the pump. I have to assume the 180 degree actual firing point of the injector is determined by sprocket ratio of course. But it is useless to speculate until we have some indication of the voltage/degree relationship. Or if indeed what I am concered about also that the engine variences are really important or not. The injector condition as to pop pressure is for sure in my opinion. Again without proof accuracy of degrees being probably at 1 degree at .1mv or less it will not fly except as an approach to clean up real errors mostly introducted to pump by us to some exrent. On the otherhand I really visulise other applications to run down other problems with this methology. It is perhaps the only dynamic service tool we will ever have to service these engines at home. I hear all your justifieable concerns by the way loud and clear as have been there and for that matter still am. Actually there is a plan. When we get to a certain intensity or progress the engineers will step in. I suspect they are having some thoughts at present. Things are revolutionized by simple things once in awhile. They are well aware that simple ideals quite often upset complex applecarts. We could use their suggestions on the ratio problem although I have thought of quite a few ways to get it that are not too complex at all. But do involve some time building the test gear as at least that much has to be very accurate.

Tomnic, I might have spelled it wrong. Since I really do not know much about pumps it seems to me that changing the internal cylinder volume does change the point in time the pop pressure is reached. Either more or less as the piston stroke is not changing or the bore in the pump but the equivelent of the head is being raised or lowered on that cylinder. Anyways the cravat again is unless in an extrene condition what you mention might become so depending on the results and knowledge gained by certain tests not yet done. Until more is known it is bad to even contemplate touching them. Reading the glow plug voltages might give a person something to ponder and speculate about with absolutly no harm done. What you speculate about may eventually become true, there is always a slight chance and it would be good. Also may not be as simple as thought at present.

i wish my 603 allowed this kind of tinkering.bosch changed the pump from the 617.ive got 1 cylinder thats off as well.hard to tell but if you seen and heard a sweet running 603 or 617 it kinda makes you envious