Sounds like a delivery valve problem to me. They can get seized and not allow fuel to flow. Take it out and see what it looks like.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

Are you talking about the new ones that I just put into the pump? They are new and 100% clean and as perfect as they can be. Again, the pump is new (within a 1000 miles).

Hang in there brother. I'm taking delivery of my first diesel next week and as annoying as a problem can be your misery does help others. Good luck I know you will fix it.

Okay you are probably pretty frustrated about now. At least you may have identified a problem.

Frustration stops the logical process of the brain functioning well. We have to chill out when this occurs. I always left the job and did another one myself to cool down.

Anyways get the number one hard line off the injection pump. Have someone pump the primer pump constantly when you are rolling the engine over. Fuel should squirt up into the air from the number one element. . If it does do the same test without the primer pumping. This should prove one way or another the lift pump function is present or not.

Fuel not present with either test may indicate the shutoff on the injection pump is remaining on. You stated the shaft O ring was missing in the lift pump.

Check your oil level for being really high. For example without the O ring excess fuel could have been pumped into the base oil. Certain conditions can cause the engine to keep the injection pump shut off device on.

High engine base pressure to be exact. If you want to narrow it down to being the injection pump or whatever some of us may be able to suggest a few easily done tests.

Personally I would want to do whatever it takes to get decent fuel coming out of the number one element first or find the reason it is not. My tests are usually pretty simple to do and cheap as well. If you will do this test and come back on the site with the results many members may be able to help.

Now at the end of the rainbow if something like the injection pump is proved bad used parts can get you going cheap enough. Also try to look at the upside as there is one. You are not dealing with a random intermittent situation.

Thanks. I should have updated the last post and said that I didn't realize at first that the O-ring was in there. It is a little hard to see after you pull the rod out. Anyway I got it out with a pick tool and it was in perfect condition. I replaced it with the new on in the Bosch kit regardless.

I sort of did what you said but loosened the injection pipe on the injector side and not the pump side. I don't think this would matter at all unless somehow the pipe itself were plugged up but all of them would have to be clogged to cause this issue so that is doubtful to say the least... which brings me back to that cam/lobe that is moving the lift pump, or the IP. I never had one apart so I can't guess if that can screw up in a way that would cause this whole incident.

Has anyone seen the fuel stream that comes out of a good lift pump while the engine is cranking/running? Using the hand pump, the return hose was giving me what I'd call a healthy urine type stream of fuel into the bottle. When the engine was cranked over, it was more like the urine stream of a 100 year old man's or worse... if that makes sense.

I think you've pretty well isolated the problem to either the lift pump, the injection pump, or the injection pump timing (IP timer and/or timing chain).

Have you checked the injection pump timing yet?

I'd recommend you check the injection pump timing as your next step. If that is good, then you need to start looking for a replacement injection pump. If that is bad, you need to dig in to check the timing chain wear/stretch (easily enough done by pulling the valve cover and rough check vs. the marks on the camshaft bearing caps) and then the IP timer device.

Lots of folks on this forum in CA, maybe someone has a spare they can loan you for test purposes?

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Hopefully someone will chime in on this, I've no experience here. Is the lift pump driving cam (inside the injection pump) visible when the lift pump is removed? Can you measure the up/down movement of the cam somehow, and someone can tell us what normal range should be?

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

While cranking or idling, the lift pump should be able to produce a healthy stream, it needs to produce and maintain13 psi internal IP fuel pressure. You said you "rebuilt" the lift pump with a kit? Maybe something went amiss in the process. I'd get a good used lift pump or bypass it all together with an Airtex solenoid pump temporarily (very easy to set up) and if it starts and runs well, you've found the problem.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I would now move to absolutes. A piece of clear hose in the return line or it submerged in a container of fluid to make sure there is not a lot of air in the fuel being supplied to the injection pump. The ten dollar liquid dampened 0-30 pound pressure gauge from harbor freight or another source gives another needed absolute.

Observe the position of the injection pumps shut off lever with someone cranking the engine. I too suspect issues with the injection pump but would have to be absolutely sure the fuel supply system to the injection pump is as it should be first. The vaccum shutoff is acting correctly and the alda or boost fuel circuit has not developed a rare defect either.

Far too many injection pumps have been changed simply because the supply system was not checked out properly. On the other hand if the injection pump has issues prove it has first. They can fail. Even I think and suspect it may have but still am not absolutely certain enough at this point.

This is getting almost humorously bad. I was able to get it started today but it has to crank many times before it finally fires. I prime it first until it "squeaks". I hold the throttle open and it climbs in RPM and sounds very normal. It will sit at a higher RPM smoothly like this but after about 5 seconds of this it starts to slow back down then just dies. It will start again sometimes but run for a few seconds and die again. It wont idle much at all. I am still bypassing the fuel tank with a bottle full of Purge. I used that up during testing and it now has diesel in the bottle.

I repeated the fuel pump test by putting its outlet hose into a bottle. I had someone crank the motor and the fuel that comes out is MUCH less than if I hand prime it. Like I said, the pump is in new condition and has NEW valves in it since a few days ago. It is SPOTLESS inside. This again makes me think it is the IP not giving enough movement to the pump's roller. Although why does it run well for that short period?

I am at the point where I'm pricing tow trucks to get it to a Mercedes shop that was recommended. I went there to check it out and talked to the old German guy that owns it. They had 5 other 617/300D cars getting worked on. He charges $80 an hour which could be worse. I will have to go this route now I think, although I have to save up the money to pay him and the $100 tow fee! SUCKS.

Have you put a clear line at the cigar hose yet? I repeat: It is not normal from your description of the lift pump output. If you want to insist it is fine because it is spotless and you just rebuilt it, not sure what else to tell you. You need to do the easy things first before blaming the IP. Another test you can do is measure the internal IP pressure, that will tell you if the lift pump and over flow valve (the one you stretched the spring to 27 mm) is doing its job.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Well it would be completely illogical for the pump not to be perfect after the full breakdown and inspection/rebuild, and the fact that it has so little mileage on it to begin with.

No I haven't done the clear hose because, for now, I have the cigar hose stuck in the bottle with the fuel and the intake hose. Regardless, even if there was a little air in it, I wouldn't think that supports the symptom currently described... a complete shut-down after a short run. Also, if it did have air, where would this come from? All my lines are new, tight and drip-free. And how do you check the internal IP pressure?

I think you should tow it to the mechanic.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Whatever. The symptom has to fit the "try". If my headlights were dim, I wouldn't spend my time inspecting my rear view mirror. A clear hose isn't going to tell me anymore than if the hose is in the fuel bottle. I get the feeling you are making some assumptions here but I''m ahead of the basics here by far and spent far too much time going through all the obvious. I assume few if any here have dealt with the cam that moves the pump which is why we are all trying to look other places.

Logic points to the simplest answer which is that cam or whatever might make that an issue. After I see it all out in a shop, which is better equipped than I, I will post the answer. My first guess now is the IP, second is the timing device/cam.

I had my fuel supply completely disconnected and could start and run it several times, much to my frustration. So, to my logic, fuel issue, most likely not enough.

So since you checked chain stretch and timing, how is it? We have yet to get that report.

For the same or less, you can get a year of A.A.A. and three tows! I don't like A.A.A. in Comufornia as can't tow to a residence, but out here got away with it. Please, consider your options. Any friend with a tow hitch? I [B]hate[B] Uhaul, but if you do all the safety checks you should get away. And for $30 way less!

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Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.