I posted this and similar threads on a couple related websites hoping to get an answer to my problems. The named engine is marinized and installed in my sailboat since 1997. Up to this point the engine has 1,272 hrs (x 50 miles=63,600 miles converted). Mind you, a boat engine is far less exposed to ups and downs compared to land cruising. Ever since it performed flawless. To get a picture of my rig—here a bit of history. This engine I had in mind buying in 1974, I couldn't because the mechanic was still engaged in a complete overhaul. Instead I bought from him an OM 621 ready to go. 22 years later and half a million miles on it (the mileage already on at purchase plus engine hrs x 50 miles) I proceeded to give the engine a complete overhaul. Thinking that old Peppi (the mechanic) may have some needed parts I called him and found out he had died shortly after he had finished the overhaul on the OM 615. His son was not interested in any shop work, so the engine sat dormant for 23 years. I bought it! With my mechanic-friend we checked it out, and the specs were close to a new engine. I thought this explanation necessary to fathom what I'm talking about.


Last Summer, the engine became increasingly harder to start to no start. Installed new glow plugs, adjusted the valves, new injectors, new chain and tensioner, timed it correctly—still wouldn't start. Found that the diaphragm was leaking. After replacement, still wouldn't start. Found that the first cylinder didn't get any fuel. Got Bosch Service in Richmond to repair the pump. $788 later still wouldn't start. The compression on a very cold engine (January in Virginia) panned out +300 all across. Since it won't run I had no chance getting it hot. This may be low, and only God knows what it would be hot. But with everything else correct shouldn't the engine start? Any help as to what I must do is much appreciated. Hein

Sounds like your engine should run well. You have tried new fuel? If not feed the injector pump from a can.
Try to get the engine to fire by spraying some wd 40 into the intake. The only variable that occurs to me is the chance your pump was not timed well when you re installed it. Make sure you are getting fuel at all lines by loosening off the injector lines at the injectors one at a time.
You may have put new glow plugs in but are they heating? If not this would do it totally.

thanks barry, glow plugs are heating--bars are very hot. Fuel is good. Timing is right on. I may blow a lot of hot air by mentioning what I did: a simple form of leak-down; connecting a gauge to the GP adapter and tried to blow compressed air into the cylinder. I made sure both valves were closed. The air escaped as quickly as blowing in. I sealed the exhaust and dip stick loosely with plastic to detect any crankcase leak. Nothing visible there. The only other possibility that the air escaped into the head which i was unable to determine. Now, by taking off the head I should be able to find the valve seats ok or not? With the head off is there any way to determine whether there is any leakage past the rings--how would I do that--squirt some liquid into? Any suggestions are appreciated. Hein

PS. all lines are getting fuel. Also tried WD 40. Once I get it started we may visit you in Nova Scotia--our dream.

seems near impossible to have a leak in a cylinder and have 300psi + on the compression test.
question,what are you meaning when you say that the fuel is good?
larry perkins

Crack the injector lines and see if you are getting fuel to the injectors when turning it over.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Pay attention and answer any questions very thoughtfully as they are posted. There are some real experts starting to post on your thread. I am not one of them. There is already a bit of conflict here in your descriptions.
If you had 300 lbs cold compression you could not be loosing air really fast when injecting into the cylinders unless you had some kind of baby compressor in my opinion. Even then it should not be so I think but a really tiny compressor might do it.
Second point is you would hear where the air is escaping to from either the oil filler cap or intake air breather area or out the exhaust. There is just nowhere else it could go. Also with 300 lbs cold compression across the board and hot glow plugs the engine should have run a little on the wd 40. Something is wrong with this overall picture. You do have the same starter on the engine as it last ran with? I just thought mercedes might have made a reverse turning engine for marine applications and of course would have to have a reverse turning starter for it. If the wrong rotational starter was on it would be kind of hard to run that way. Just having a look at the direction your prop is turning will answer the question if any doubt perhaps. Again the real experts on site are starting to appear on your thread. They will get you running or help you find the reason it is not. I really hope you have not started to pull that head. If you have stop or do not even start to.
One last thought is you were not trying to get this diesel running at really cold temperatures with no block heater? Your problem will either be resolved fairly quickly or it will become an interesting thread. We are very fortunate to have a good group of practising mechanics on board.
I also still sail a little but only have an albacore and inland scow for fun now. We have the warmest waters north of your location out at the beach.

by FUEL GOOD I mean I took aboard 100 gal. late Summer 06 and treated it with stabilizer as described--I do over the past 30 odd years. The prop is matched to the engine. Checked GP and compression again today--compression 280/315/320/280. Why the variance to last time I don't know. As of GP: to test them I prepared an alu bar some time ago. Drilled holes and threaded them to the exact spaces apart. Hooked them up exactly as if on the engine, hooked up the power and ground lead. This way I'm able to test the entire system. The GP's show red after 25 sec..I also cleaned the holes on the block. To rest any doubts about the condition of the fuel, I hooked up a tank with fresh fuel directly to the prime pump. I drained the Filter and pumped until I was sure the system (filter and IP) is totally purged of old fuel. Using WD40 freely, it wouldn't start. There were signs it was about to start but didn't. What confuses the whole issue are the multitudes of recommendations on how to install an IP. MB Manual and MB Workshop Manual, here a direct quote: Before inserting the IP , check again whether the piston of cylinder 1 is in the compression stroke and the crankshaft has such a position that the adjusting hand on the crankcase point to 45 degrees BTDC on the gradation of the counterweight. The adjustment of the crankshaft to 45 deg BTDC is required because of the jumping back of the follower by 2 teeth. End of quote. This is also what the specialist at Bosch repair suggested. I simply matched the marks on the IP, the mark on 24 deg. on the gradation and inserted. Another dispute is over where to put the start/stop lever on the injection pump while timing. From Haynes I gathered it should be in Start position. From others in Run position. Tomorrow I will time the pump again--in Run position. I also will recheck the valve gaps. It may appear I'm a total nincompoop--I'm not! I fooled around with MB diesels for over 30 years. What is happening now is a total mystery to me. And be assured I'm grateful for any suggestion you may have, and I must be stupid not to follow good advise. After all, it is the reason I'm with you. I will report. hein

Questions first (and I'm sure you did most before fiddling):
1. What RPM do you normally run the engine at? You are probably aware that these MB engines like to run fast as compared to a Perkins, and coking or carbon buildup is the result of lugging an engine. Pre-chamber or valve seats is first place to look. I wouldn't pull the head just yet. The engine should start at your compression if everything else is OK. Sounds like you know how to properly install glow plugs and injectors (new seals every time).
2. Are you sure about your fuel? Dewatered? Do you use a water separator?
3. Electrical contacts clean bright and tight? Including the grounds?
4. Battery OK? Starter getting tired?
5. Did something (other maintenance) mess up the linkages - get the tickler installed correctly?
5. Hand pump OK?
6. Then the obvious - air intake and exhaust not plugged? What are you using for an air filter?
7. You said the starting got progressively worse. To me this says any of the above (except bad fuel and linkages).

After the above, if it was me then I'd pull the valve cover and verify the crankshaft timing marks with the valve springs. You may have to loosen up the valves a bit to get a good "feel" and use either your finger or a gage on the pre-chamber to verify the piston. Check all the cylinders and look for "extra" marks - the injection pump may have been timed by ear after a rebuild and before you started fiddling - hopefully you marked the location before fiddling. This may take some time - not fun in a boat - I'm sure you know timing chain stretch will "mess up" the marks, too. I'd take the injectors to a good shop and have them cleaned and balanced while you're doing this - they'll be done before you.

Then pull and install the injection pump in accordance with MB and Bosch instructions. Then time by drip tube to where you know it's supposed to be - you found that by verifying the timing marks. Then adjust valves and button it up. Prime and give it a try. It should start and you may have to adjust timing a bit - by ear. And I'd take it easy on the WD-40 - much better to have known-good-fuel.

After all that (and a sore back) you may still have to clean the head, especially if the engine's led too easy a life.

__________________
daBenz - 1970 220D

Thanks for the suggestions. What you say about RPMs is certainly true. Normal cruising is 2300. I can't say whether the tach compensates for the 2:1 reduction--alternator pulley to the crankshaft pulley. What I know from other MB boat operators they cruise at the same RPMs. At that I get 6-1/2 to 7 knots out of the boat. That is max what one could expect. What certainly is a detriment that the engine is also used for charging, anchored for a long time when the RPMs are kept at 1200. On the other hand I removed heads half a dozen times from the two engines I had in my boat over a 30 odd years of operation. None of them showed excessive carbon build up. In addition to the 2 filters on the engine is a Racor Filter/Water Separator. The starter I taken apart and smoothened the armature/collector, brushes all look with plenty of life left. Starter is only 2 years old. Primer Pump is new (the new type.) The pump itself was reconditioned with the IP by Bosch. New Battery. Cables are in perfect order. Now to something I haven't done: First, what is a TICKLER? Also VERIFY THE CRANKSHAFT TIMING MARKS WITH THE VALVE SPRINGS? Also HOW TO GET A GOOD FEEL AND USE EITHER YOUR FINGER OR A GAUGE ON THE PRE-CHAMBER TO VERIFY THE PISTON. Always something new I haven't heard of. As the saying goes, a picture is a thousand words. I enclosed two. Many thanks, hein

no one thinks you arent experienced,believe me i have made plenty mistakes.
the thing i cant get past is that the compression is good but yet wont hold the air pressure when you applied it to the gp hole. i once got tdc set but was on the exhaust stroke,so got ip in and 180deg off, that sucker started,but after an rebuild i knew it should run better and cooler,lol.
so the only logic i can apply is that there is a timming issue?? valves are open when you applied air pressure??
i do know that it can appear that the fuel system is working correct,but the relief valve on the ip can stick open and the pump cant get enough internal pressure to operate.correct me if i am wrong,but i didnt see where you cracked the lines to the injectors to see if fuel was getting there?? i just take a clamp(vice grips) and clamp the return line to the fuel tank and crank to see if the relief valve is the problem.
larry perkins

i forgot to mention that some of the ip's are marked wrong in reference to the timing mark,i didnt go read again right now but my memory says to make sure the timing mark is lined up with the 10 oclock screw if not then use the center of the screw as the mark on the ip.
also imho,the issue with the throttle position of the ip is just when you are completing the drip tube final calibration,the pump throttle should be full open which on a standard 220d engine is the start position,all you are looking for is to make sure fuel will run freely thru the drip tube while the ip plunger on #1 is comming to 24 deg btdc then at 24 deg the plungers top gets to the bore and shuts the fuel flow off(or as we like to set at 1 drop per second)start of delivery.
hope this helps
larry perkins

Windjammer, the tickler is the shaft/rod assembly that runs from the throttle body over the valve cover (in a car setup) and down to the engine side of the injection pump. Senses minute changes in air pressure (from minute changes in air speed in the throttle body) and "tickles" the rack in the injection pump - at idle speed. This is not the governor circuit, which I'm sure you know does the same thing when the engine is under load. The engine would "lope" or hunt around at idle if the tickler wasn't operating correctly. Normally shouldn't be an issue when starting, but if installed "way off" then it may interfere with the rack at the wrong time (starting). Been there.

You said you replaced the timing chain and rails as an attempt to cure the no-start. I tried (badly) to explain how to ensure that the cam and crank are properly timed to each other and the crank timing marks - without taking more than the valve cover off. You may have your own way of doing this or maybe somebody can explain it better than me. Bottom line: you need to know that you installed the timing chain properly and you need to know whether the timing numbers reflect reality.

I wire-up the rack at full/start position - I don't have enough eyes and hands to turn the crank and watch the marks and the tube and the rack all at the same time. To me, the drip tube gets it close (and running) and final timing is by ear - there's too many variables to completely trust the timing marks.

I'm not sure when the injection pump "relief" changed from an orifice plate (a washer) to a ball-and-spring. My understanding - I may be wrong - it happened when the secondary filter changed to top-outflow. If your secondary filter is a cannister type with bottom outflow (to injection pump) and and a drain bolt at the bottom corner then it's basically a gravity fed system with an orifice plate. You're off-road so it should be perfectly legal to work some type A auto-transmission fluid into the injection pump and let it sit while you're doing other stuff - works as a very mild solvent.

Hang in there - you did a lot of stuff when the engine didn't start. It'll pay off to recheck things - including air intake and exhaust. Do we get a free ride when it's all over?

__________________
daBenz - 1970 220D

love the northern neck.

here are 2 pics that may give a closer look into my rig. hein

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as a neck affisianido(sp), was hoping for a 'real' picture. realestate. somb. please........