Please don't take this the wrong way........and a fellow with your experience proably had has it covered.

But, I don't see anything in the thread where you checked the valves for proper lash or the injection timing for proper spec.

I realize the head was redone but the valves have a habit of seating themselves in a new head and usually require an adjustment at 1000 miles or so.

You could be chasing an IP issue........when it's more basic..........

that is working to pull parts off of.
amazing list of problems here, I bet all the "metalic sludge" that killed the IP is bogging down the injectors. DG has a nice site with pictorials on changing out the injectors, I would order a set from him and get them in!
then I would fill the car's tank with Nitroglycerin and remote start the puppy!

Ok, let me see if I read this correctly. You're current status is back to the starts fine when cold, runs for 2-3 minutes then dies and goes to non-start.

And this is grasping at straws, but that is where you are anyway. So here goes:

Crankcase ventilation- this symptom is very similar to this being blocked. You did say this was a siezed engine at one time.

Exhaust- this sounds an awful lot like what someone else experienced recently with a blocked exhaust. Albeit, it sounds crazy and was on another model, but simple to verify by unhooking the downpipe.

Maybe we are looking at the wrong side of things intake vs. exhaust.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

I've just re-read this thread and have a couple of dumb questions. It sounds like the last time it started and ran reliably was when you purged it, but it failed to restart when you re-connected the fuel line. Will it still start from a bottle of fuel (or purge) at the pre-filter? You said it smokes a lot until warm, but runs well, you also said it started nailing badly while being purged. Are you still sure of the IP timing, would it make sense to recheck it now that you have good fuel flow to the injector lines? The smoke and nailing sound like the IP timing may be way off, is it possible that it moved after it was adjusted, or that it somehow got off by one gear tooth? Is it possible that your original drip timing measurement was inaccurate due to air in the IP? I'm just guessing here, but I find it hard to believe that injectors would do what you're describing, and the odds of a IP just going bad are pretty slim.

One last comment, my 300D completely died and would not restart a few years ago. It turned out to be a very small crack in the plastic lift pump body letting air into the fuel lines. It sounds like you have been through the whole air leak drill already, but I figured I would mention it anyway.

First off, it DOESN'T start fine when cold. It MIGHT start and run for 2-3 seconds after I've tried starting it 10- 12 times. Yes, I rechecked the drip timing AFTER pulling the pump with it lined up at 28 deg. BTDC to be sure that the notches on the pump lined up. Yes, I rechecked the valve adjustment. Two exhaust valves were slightly loose. The crankcase vent system is OK. When the car DOES occasionally run, the pulses are even and strong out the TP, so it isn't an exhaust issue. it was a bear to start, but once it was started, it would run great. Then, I did the diesel purge to try to get it to start easier, and to attempt to get any remnants of the fungus slime out of the system. That was when my REAL problems began. If you re- read my original post, you'll get the sequence of events. This car has not started or run reliably in quite some time.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

You have years of intense experience unlike me. Your gut feeling will probably turn out right. There is one question you posted that nobody has answered yet. Had to do with the amount of movement you were getting with your finger inside the pump. I do not know the answer. I guess one could check the injectors. I would not recondition them at this stage though unless it was really indicated they needed it. If it did not run so well when it started I would suspect a twisted crank in the pump. A little twist would make it very hard to start but it might run okay. That is partially defeated as it does run for 2-3 seconds when it catches and quits again but perhaps not. Got any friends in the buisiness that might do a quick check or really minimal charge check of the pump in a jig? Lots of cheap used pumps around but of unknown quality usually. Someone on site may have a spare known good pump they might dispose of cheap. Or borrow one for a substitutuion test. I think you now heavily suspect that pump now if the injectors are not partially plugged up and you are probably right. You have to be close after all you have already done and as you like the car it will run again. From a troubleshooting perspective if the injectors pop off ok with a reasonable flow what else could it possibly be but the pump itself? Although I have seen cams twisted a little on european farm tractors with no valve interference and they could never get them started. Always attributed it to soft metal in the cams and other than mercedes chewing off the first lobes on gas cams have never seen other defects relating to really soft metal cams in mercedes. But that alone does not totally eliminate them in mercedes either. If the pump checks out and injectors are really not bad then indeed it will pretty well have to be the unusual. Try to remember that I am not a working mechanic when you examine anything I propose. Just posted this because you know you are close now and mentioned you are looking for ideals. I am just about on the verge of taking a pump apart so I can really understand the possibilities of what exactly can go wrong in them.

Please provide the exact sequence of steps that you performed for doing the IP timing.

Brian, I believe he is a working mercedes mechanic with twenty eight years experience. You may have missed that. Or I might be wrong.

I think you're correct........but........when he mentioned the timing at 28°BTDC, it sort of had me thinking.........something simple is being missed here.........

We've all done it.......searched fruitlessly for a complicated problem when a very simple mistake on a basic parameter has caused us significant pain.

For everybody, I'm afraid that I'm the culprit with this "lift pump" terminology. A lift pump is from the small boat marine industry, where the lift pump moves fuel from a storage tank to a small service tank located above the engine - usually a day's worth of fuel and mostly for the gravity-fed (gas or diesel) fuel systems. A while ago, I used the marine lift pump to explain the difference between a pressurized and non-pressurized or gravity injection pump. We really should be using "fuel pump" to describe the fuel pump in our MB auto engines as our fuel pumps operate continuously.

Tram, it's time to move on, now that you have a handle on those pesky bubbles. I'm assuming you have all the leaks fixed. You mentioned that it ran 2-3 seconds then gave up and dry-cranked with an occasional firing attempt. So you're looking at injection pump plungers (maybe), injectors (probable), pre-chambers (maybe), or vacuum systems and linkages (probable).

Pull the injectors and clean and adjust - then you know the entire fuel system is clean. Look at pre-chambers the best you can: crank engine and they should puff. Should be able to see the cross bar with the ball on it. Should be able to glow and feel the heat. Shouldn't be too much carbon - if so then teach the driver to not lug the engine. Too bad you can't put a light in the cylinder to make sure the holes aren't plugged. Remember to use new shields (seals).

I don't have a spec for the rack movement - a decent injector shop should still have their books - but it isn't much and it shouldn't be a hard pull or push. Remember that the tickler overrides the governor with very little force. Previously you mentioned that the injector line clamp nuts were loose - I'm you sure you got the pieces put together right when you changed injection pumps.

Plunger test is pretty easy, if you have the equipment. Neatest set-up I've seen is a length of injector line with a tee: a known good (clean and adjusted) injector on one side and a high pressure gauge on the other. Hook up at one injection pump outlet port and crank or hand turn the engine after priming with the hand pump. Gauge should rapidly increase, then injector should spray, then the pressure gauge should very slowly decrease.

Now you're going to have to really describe the injection pump controls. You mentioned a vacuum shut-off - I get that. You mentioned that you pulled a vacuum box off the end of the injection pump. A single vacuum line going back to the throttle body (the box just upstream of the intake manifold that has the foot throttle and tickler linkages) and no where else? What about altitude adjustment? Manual (with shims at the vacuum governor) or "automatic" ALDA? Hand throttle (fast idle)?

I'm sure you know that you need a plan B in case the linkages aren't put together properly and the engine runs away. This engine will run like a sewing machine when you do get it running.

I've killed exactly two batteries in my life - both internal failures. Every other "dead" battery came back with a day of trickle charging then a night of sitting with nothing connected. One stubborn battery (a 6V that sat outside for two years) came back with only a week of the trickle and sit drill. I don't use sealed batteries - checking the water and specific gravity is easy. Two of my batteries are 15yr old - ancient for my climate.

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daBenz - 1970 220D

I wouldn't take all the responsibility for the term lift pump. AFAIK, people have been using this term for a LONG time to describe this type of pump, and it's not limited to boats. I have no problem calling the lift pump in my MB a lift pump, I think everyone here knows what we mean. We could always call it a "Primer pump assembly" like Fastlane does .

Dabenz, you cannot take credit for calling it a lift pump. It has been described as such for as long as I have been on site by everybody. I wondered about the terminology myself. It will still be described as that well into the future. If anything it is a feed pump or intermediate pump for a higher pressure pump or series of them depending on your viewpoint. Or perhaps having a return valve modifies the terminology. I think I am more the specialist on putting ones foot in their mouth. Nobody can surpass me at that. I usually insert it up to the knee joint. My pant legs are in shreds. Anyways I enjoy your posts very much as a real learning experience. Even if you do not know that what you are saying is the same as everone else is saying

Sorry, I did re-read your post. I must have lost track of the sequence of events. I was thinking along the lines, that Brian mentioned, of "it's the simple things that bite us sometimes".

Original pump: run fine at first and developed a hot-start issue. Fungus issues with running 2-3 minutes. Filters and screen.

Diesel Purge

Problems: Harder start and if it does, 2-3 seconds then dies. Noticed low fuel output from lines. Purged air from pump. Better fuel output now.

As you mentioned, the real problems started with the Diesel Purge and fungus combination. Also, you stated that there were issues, possibly, with air, etc. in the pump. But now you have pretty good fuel flow from the lines.

What is next? Did the fungus move into the injectors from using the Purge?
Possibly a dose of Biobar, try to start it in order to get it into the system, let it sit overnite?

Just a recap to help in understanding.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Turn engine over by hand with 27mm socket and breaker three rotations in regular direction of rotation. Line crankshaft pulley up with pointer at 28 btdc, camshaft #1 lobes pointing up. Remove pump. Rotate pump once in regular direction of rotation with 19mm wrench, lining up "missing" spline on drive gear with notch on pump body (on ring). Install pump. Rem. ball and spring on #1 nozzle and adjust drip timing to spec by "swinging" pump on the three engine block studs. Lock down the pump and install ball and spring, linkage, adjust linkage per manual. Re- bend and install pump to injector pipettes to fit with no strain on pump. Install vacuum line.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

That's perfect for the procedure, however, is the spec for the 240 24°BTDC or 28°BTDC? I didn't realize the 616 is 4° advanced from the 617???