hello again....still trying to track down my constant injector nailing. I am going to do a purge but cant seem to find the product in Canada. in the mean time,How much of a difference will it make in taking injectors from a 300
and putting them in a 240? My dead 300 has injectors that are only about 1 year old with less then 2000 miles on them.the part numbers are the same but i think the pop pressure is different. My 300 injectors are showing a bar pressure of 135 and i think my 240s are around 115 or 120. Is this a huge difference? what is the proper pressure supposed to be for a 1978 240D?

the #4cyl miss has gone away now,but there is a constant pinging at around 50mph,was never there before putting in the diesel clean.
very extreme when cold but is still there even at operating temps. goes away at high rpms,more pronounced when accelerating and once again at around 50mph.......Have tried driving the **##%% out of it ,no change.

__________________
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

Wade. If you are one of the two guys that moved their element settings in the last week then the problem is early injector timing on one of them. If the engine knock is eliminated by backing off the injector line on a cylinder of course substitute another injector. If problem is still there then it is a timing problem. Best first test is to study rpm drop on # 1 when line is backed off and compare drop of rpm when the troubled one is checked. If their is no noticable drop in rpm you most likely have a timing problem. The above only applies if you were one of the gentlemen that moved the two nuts on the elements if you are someone else just ignore this post.

thanks for the reply Barry,and yes i am one of the guys that moved the element.I thought mabe i got lucky and suffered no ill effects by removing the element hold down nuts,but the more i think about it, the more i think you are correct. The main reason for messing with the #4 element to begin with was because i WAS NOT getting any drop from the number 4 when i cracked the lines. after much playing and adjusting and cleaning of the elements about 10 times, i managed to get it idling nicely on all 4 cyl's.
so now it starts nice,just like it used to, and idles nice (once its warm) but the thing is pinging like crazy at just about every rpm..very high seems to be the only smooth setting. And until it warms up there is a very definate knock on at least one of the cyl's.
I already know that when the car is idling nicely and i crack the #4 line,there is a definate drop in rpm. but something is still very wrong with either the injector timing or the injector itself. do you know of a way,if there is one,to adjust the element or in my case reset it back to the way it was,without removing the pump from the car and getting it bench tested.
I think you are on to something here.........once the nuts are loose,there is really only about 1/4 inch that they can be adjusted either way. is it possible to adjust them a little at a time (trial and error) or is it way to fine of an adjustment to even try that?

__________________
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

one more question.who was it that is supposed to be the guru on these fuel elements and adjusting them? is it Larry?

__________________
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

Okay wade I just happened to get back from checking that you were one of the two. Since you had the number three element out as well it is a little more complex now but still possibly managable with trial and error. Find out what injector is causing the principal knock just by backing off line four and three injector nut one at a time with engine running. If so I believe I remember you checked initial pump timing reciently. Like in the last few months? As I see it by trial and error move the element a little at a time until the knock or pinging is gone. This will take some time as you are going to have to shut down engine between adjustments of the elements position. We are talking about very small incremental movements of the element position now. Since it is the four cylinder and you have no tach refference you will have to listen very carefully for the same rpm drop from #4 to say #1. If you get rid of the problem and car runs well and fuel milage is ok you can leave it at that. The next proceedure is subjective. You take the wire off the affected cylinders glow plug. Fasten a voltmeter on the millivolt scale from the glow plug to ground. You then move the element by incremental small steps to locate the highest output voltage from the glow plug. This would tend to maximise the proper timing of the element to that particular cylinder. Now if the injection pumps basic relationship to the engine is good (drip test #1 to crank pulley location)you might pull this off. If you cannot do the above steps with patience or satisfactory results are not obtainable then a used pump may have to be installed. Far cheaper than sending your pump to a service depot. Also you may learn a lot from the experience. I have not done the meter test but after spending twenty five years in electronics it does make sense plus is the proceedure to ensure proper highly accurate pump timing by quite a few manufactures so cannot see why it will not work. My last thought is there are tachs out there that read rpm from vibrations for service of diesel engines. If you could beg the loan of one it might expedite the matter in the simplest application of rpm drop comparisons. The concepts are not tough if you think about them. Now the most important issue. In your mind you never had the ping until you moved the elements? Because thats about the only way you can be certain of the cause of the pinging you describe. The ping or what I would describe as knock is caused by the injector discharging a little earlier than it should causing preignition that is hard on the engine. Also since you had those two elements out you have basically nothing to loose as it is mathamaticaly pretty well impossible to put them back in the right position by just dropping them back in. Anyways if you want clarification of any of my thoughts or any questions that pop up perhaps you would preffer to private message me or to continue this thread is okay by me as well. I was also trying to forment the easiest way to visulise what you are trying to attempt. Well this is the best I can do with my limited intelligence. Draw two circles. One about say eight inches. Draw another circle inside the large one about five inches in diameter.. Place four injectors symbolically at 90 degrees on the inner circle. Then draw four cylinders one above each injector on the large circle. What you are trying to do basically is slide the number three and four injector elements along the inner ring until they release pressure at exactly 90 degree intervals in relationship to the number 1 & 2 elements that you have not disturbed. This is just for basic concept as in reality the release point is 180 degrees as it is a four cycle engine. The better concept you have of what you are doing improves the chances of success. I am not suggesting that anyone ever move the elements in the pump but these are known to have been moved by wade reciently. The last time I went through this there was ample evidence that the injector was releasing earlier as it had been substituted with a known good one yet the pre ignition was still there. His was so severe that when he released the line nut the engine even gained rpm. That enabled me to target the problem to a bad pump or bad output calibration. It turned out satisfactory I believe. The previous owner or a garage had removed the #1 element to do the initial pump timing I believe instead of just injector line fitting. **** happens as wade has found out. Guess actually there was another example. A leak was detected at a mercedes garage after a fairly minor procedure. The mechanic way overtorqued the line nut to stop the leak. I believe in the process he moved the element position. As that cylinder had pre ignition problems afterwards. What I never found out was if the dealership fixed the problem or stuck the customer. The last communication was the dealership was still fooling around just changing the injector etc. It never fails to amaze me how long pumps in general last as they are precission assemblies and many problems could develop internally but on the average do not.

great info,thanks alot Barry...one thing i should point out. I never did mess with the element adjusting nuts on the #3 cyl, just the #4 cyl. learned my lesson after that one. i simply removed the element from the #3 and placed it in the #4 spot to trouble shoot my problem after i took the entire element out of #4. so once again, the only element adjusting nuts that were ever played with were the #4 ones.
So i am hoping that since it is just one miss aligned injector,the process to (trial and error it) back to the right spot wont be as hard as trying this with 2 or more elements out of whack.
I dont know if i quite follow the technique you describe using a volt meter to test the timing of the injector though,can you mabe run it by me again?

__________________
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

Wade that was quite a relief to find out only number four element was really disturbed. The meter thing goes this way. The glow plug acts as a thermocouple. Being made of different metals (alloy)when it is heated it generates a voltage output. It will generate the maximum voltage output when the cylinder is operating at it's hottest or most efficient point. That is the timing the manufacturer strives to obtain. It is the most certain way to put that element back but like most things there are complications like the voltage would have to be read at exactly the same time interval after you restarted the engine each time after each adjustment. Or the pumps timing is not optimum with the engine and therefore you have great timing to that one cylinder but timing is off a little in comparison to your other elements.Still no knock though. This I suspect would pass unknown and is tollerable if pump is timed by drip method say in the last year period. Plus I am just skimming over this so there may be something you will think about to make the approach easier. You are searching for the highest reading voltage wise you can obtain. I expect it to be under 300 mili volts by the way. If the theory is correct it should do it. Things are really being simplified here as so many possible variations of the actual condition of parts etc. are not factored in. An accurate comparison count of the rpm drop is also very dependent on the condition of the individual cylinders etc for example. Plus generally speaking the injectors should be pretty even but are probably a little out of condition. It is going to take up some time as well as those incremental movements are going to be very small once you locate the general area. Very light taps might be the best to move it when you loosen up the nuts. A clue is if you are still loosing rpm now about the same as other cylinders when you loosen the injector nut you may not be a long way from the finish position now. I suspect the rpm drop does not have to be checked when searching for the highest voltage. It will automatically already be in maximum drop position when voltage is the maximum you can get.The other factor if you consider it is you are starting from an unknown position and going to an unknown position. I really think you will solve it enough to satisfy yourself and post the results both good and bad as a few people will be interested. Remember the simple part. Wire removed from the glow plug and meter reading between glow plug and ground. Hook it up so the meter stays connected for the duration of the test. Engine should start ok with only three plugs hooked up if not too cold out. Or start it with all four connected to warm it up and disconnect that glow plug just before test initiation. The engine certainly will start warm with three working glow plugs. You do have the small non series plugs in your engine? The large plugs would possibly require a little more ingenuity but test still possible. Too much information possibly but the more That is left out the greater the possibility of it not working.

OK,makes sense to me now!!!! I do have the small pencil type plugs,so hopefully the event will be successful!! i wonder if it is possible to do this adjustment with the engine running? or would there be a massive leak at the IP housing when you loosen the adjusting nuts?...........what is it about these cars that you just cant leave alone? I have a brand new truck in my garage that i never drive because i am totally addicted to my old MB.Any other car i wouldn't care about,and just look at it when i made the time,not the case with the old 240D!!!!!!

__________________
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

sorry one more thing. with all this other talk i forgot about my initial question.
with the bar difference been what it is,from the 300 to the 240,will the new 300 injectors function properly in the 240? the pressure stamped on the 300's are 135 bar and i think the 240's are around the 120 mark.

__________________
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

On the injector question I do not know. If further responses are not forthcoming you might call a pump and injector shop for information. Also suspect it was mentioned on previous posts so you might want to check the archives. I agree having two 240ds with almost perfect engines that it is a joy to have them running well. Perhaps posting the injector question in the tech section may bring a response. I also considered doing the element adjustment with the engine running but without positive reinforcement from someone knowing more would not consider it. Hydralic fuel can cut like a knife under pressure so I have always respected it.

On another topic I purchased a good 1984 300d not running last june or so in puke green. The car was deserted at a service facility and I would only pick it up if the ownership became available. Good news as the guy phoned an hour ago and the ownership is in his hands. But it has been awhile. Price was 500 american and needs starter and quit on the highway in really cold temperatures using a single tank system with limited heating. Suspect he was using mix of diesel oil and vegatable oil but do not know the proportions. There is a booster pump back by the tank I noticed as well. Think it just jelled up really as failure occured in january and it must have been pretty cold. Only wonder if the vegatable oil sitting in the injection pump for this long has done any harm. Probably not unless moisture was present in it. But is beyond my scope of knowlege really. We will find out soon enough I guess. Superficially the car is above average with perfect interior and I found new total exhaust system, both front tie arm assemblies replaced, new Idler arm kit, four new rotors and two new calipers. Almost looks like it was repaired just before the long trip he had embarked upon. Odometer is 159k miles but as usual I have to take it with a grain of salt. The previous owner said it had been running perfectly till it quit on the highway. Or thats what the owner of the service place told me he said. As in a lot of these cases I just hope for the best and see what the real story is if other than described. That green colour is something else but again something that I will get used to probably. It is the original paint and perhaps looked better when the car was new. Also noticed no clearcoat lifting anywhere or sun fade plus the dash has no cracks. Even around here uncracked dashes are not too common.

ITS FIXED thanks Barry. I am not sure if it was just lucky or if adjusting the elements is supposed to be as easy as it was. From what everyone was saying,these are the one item not to be messed with on these cars. I am sure that there is a much finer adjustment that can and possibly should be made, but what i did totally got rid of the injector knock and restored a lot of lost power.....here is what i did.

-started and warmed up car,then pulled wires of glow plugs.
-as per what Barry said measured milli-volts of of the suspect cyl #4
-came up with a constant reading at idle of 5.4 milli-volts
I realize that comparing other readings off of the other cyl's is not a good comparison to make to establish a base number,because each cyl will be running at slightly different temps, but i got curious and thats just what i did.
Well guess what? cyl's 1 thru 3 were all exactly at 9.2mv's.
-so i shut off the engine loosened off the adjusting nuts on #4,and
tried to move the element holder.To do this with any success with the
engine turned off, is almost impossible.you need the running motor
to gauge your process. so i made the decision to try it with the engine
running. I loosened the nuts just enough to move the element with a
breaking bar,started the engine and it ran with no leaks whatsoever.
-moving the element counter clockwise actually made it run worse
and lowered the mv reading further. clockwise however WOW!!!
only about 1/2mm from where i was at originally, it sounded as if
you added a whole extra clyinder. I played with different settings
and eventually got it to a reading of 9.4mv's as well,and by virtue of
this,ended up turning down my idle by about 300 rpm!!
after resetting the idle to around 700 rpm, i took one last milli-volt
reading of each glow plug, and ended up with around 8.0mv's each,
a little lower because of the decreased idle.
Took the car out for a ride,and there was NO pinging ,zero, not even a little....its never done that!!!! also a very noticeable power increase.
So like i said, i don't know if there are more hidden risks that can bite you if you play with these elements, but from what i just experienced, I would not hesitate to adjust these settings on the IP if they were suspected of been out of whack and causing your car to not run properly!!!!
Thanks again Barry

__________________
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

Hi guys,thought i would post this to generate more comments and to mabe get an answer on swapping injectors....

__________________
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

What is this " element " you are adjusting?

__________________

When the power of love overcomes the love of power the world will know peace.
Jimi Hendrix

the fuel element itself that screws into the IP. on either side of the fuel element(delivery valve) there are two nuts that hold the entire assembly in the injector pump (IP)you are in theory,never supposed to move or remove these holders,because they are a very fine tune for the individual cylinders.
I made an error while trying to just remove the delivery valve, which can be done by simply turning out the valve, and not removing the holder itself,which is held in place by these two nuts. so these posts are in reference to somehow getting the proper setting on the fuel elements, if(like I did) you messed with the holder settings (ie, the two nuts) and did not just unscrew the delivery valve itself,which can be done with no ill effects.
Usually, if these two nuts are removed and the element holder is twisted at all, you need to remove the entire pump and have it bench tested.

__________________
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

Good going wade and good expansion on the proccedure. I hope this opens up a good discussion with both negatives and positives. Now that you are a convert it has also occured to pass along a few other things this is applicable to. If your finish voltage had been higher on number four than the other three cylinders your overall injector pump timing may have been lagging a little. In your original post I think you mentioned you had checked the principal timming on your pump some time ago probably by drip method and if you did or did not it is pretty close if not dead on. Also I think if you did a compression check of your engine all cylinders would be pretty close as well. Plus your injector flow rate and atomazation seem pretty even This I figure you have already thought about. Remeasuring the voltage out put at say three quarter throttle will also reveal or dicredit certain problems that are inherent and since it is a dynamic test is very useful for certain things I believe.For cylinder drop testing as kind of a dynamic test or perhaps to localise problems the drop in mv could be used as a substitution for a tachometer for service applications. A lot of 240s if not all do not have one. You obviously have thought it through by now and will Hopefully expand on the ideal. It is not a new one and really do not know why it should not be applied in a more general way. I originally intended to generate all the applicable numbers and proccedures myself but have not had the time to do so. The main thing is your car is running well now.Also luck had nothing to do with your results in my opinion. Reading the mv replaced that. Plus you found adjustments can be made with a running engine and I was not sure of that. You also proved the general refference with the other cylinders was possible and workable. Plus you were able to refference the overall pump to the engine quite well. Now if someone is able to find out how much normal adjustment range is possible from the pump people within the total movement range of the delivery valve we will be able to establish how few degrees can be worked in. Example if total range of adjustment is say 10 degrees to allow for manufactures tollerance and wear the pump experiences over time. You would have been down to working in a single degree incremental range and possibly less and as accurate as a factory test jig. Your effort indicated on first examination that if number three was off as well you might have restored it as easily as the other. Basically with properly though out safegards and quite a bit of testing and calculation we maybe will be able to do primary calibration of certain functions of our own pumps as they do drift a little with time and wear over the years. The concept again is not too involved. We can restore the pumps output timing to optimum perhaps. But first a lot of numbers and thought will have to go into it. For the time being the old cravat of leave it alone if not certain of a problem will continue to apply to the pump. In the past pump issues have been treated too much like black magic. Hopefully as a group we can start to move past that. As soon as we are aware of the degree relationship to say .2 mv we can start the ball rolling I suspect. I realised it was inevatable in some form or another awhile ago to be able to at least properly check the injector pump out on the car ourselves as how can you chase marginal milage complaints down without being able to establish the principal components are up to speed to start with. Plus all these semi bad idle situations that exist. Just a few thoughts.