Blocked or frozen return valve maybe.
loosen the banjo bolt on the engine side of the IP and see if you can prime.

You may have a frozen check valve in your lift pump, which would completely eliminate any pumping action. If your lift pump isn't getting any fuel to your IP then that could be your issue. If this was my engine, I'd be rebuilding the lift pump before messing with the IP any more. If I had a spare electric fuel pump laying around, I'd plumb that in as a lift pump and see what happens.

Good luck.

I agree with above that I need to focus on lift pump first. I was able to order a rebuild kit for the lift pump from the local Mercedes dealer, they said it was the last one in the country.

I can't seem to find the gasket for where the lift pump mounts to the IP anywhere, what would be the best material to make one out of, or does anyone know where to get one or a part number? Thanks

Google search Mercedes 300sd fuel pump gasket,one Co. has 90 some.

Monark Primer Pump
 

I bought an all metal pump on Ebay from this seller:diesel-parts9000. He is in Germany and is not responsive to questions about whether the pump will fit a particular model car.However the pump is inexpensive ($6) even with 1 week delivery ($11). I think these small pumps are very common and are a pretty universal fit.They do move alot of fuel compared to Bosch,black pump.He also sells Monark fuel injector nozzles. Hope this helps.

Update of where I am now, I finally got a rebuild kit for the fuel pump. It helped a lot, but still not running, closer than I have gotten the car before though, it starts but then quits, and once it quits it will not try catch again unless I get out prime the pump and do the glow plugs again.
Here is a playlist of a couple attempts. Is it running out of fuel?
Also I think the starter is going bad you can hear it in the video labeled "Bad Starter?" sometimes while cranking it whines and stops. Is there any danger of harming the flywheel? Just want to know if I should replace the starter before making anymore attempts? Thanks!
https://www.youtube.com/playlist?list=PLvgmjy_Xf0abGLVKvFW_SkF9jYdsJCbf6

Got it running. Sounds rough but running.
Next up I am going to do a diesel purge, readjust valves, oil change, and clean tank. Probably change fuel filters again after the diesel purge. This thing sat since 2003 so.

https://youtu.be/lV-OB4f03GI

Starting Woes
 

#1 : the starter sounds O.K. in the five videos, the battery isn't fully charged and you failed to keep the throttle fully depressed each time it tried to start, a common newbie mistake ~ once it's running you MUST keep the throttle pinned until it's running on all cylinders .

Yes, it sounds too loud and too fast but there's a governor inside the I.P. that prevents excessive RPM's , it needs to run a while at a goodly clip to self bleed all the air out .

Looking at the last video where it's running O.K., the clear plastic line returning fuel to the filter, shows no bubbles .

Looks like a very nice car there, if you're careful and deliberate that original paint will buff out and shine up nicely, remember to WAX IT to keep it looking sharp .

Remember : the clear plastic fuel intake screen needs to be CLEAR not translucent, this is so you can spot fuel problems (air intake leaks, fungus etc.) before they bring the car to a halt .

The devil is always in the details .

Thanks Nate! Yeah I never had a diesel before so thanks for the input!

The Basics
 

Not many W114/115 owners / enthusiasts her but an amazing amount of collective knowledge so ALWAYS ASK ! .

I don't know if there's a factory service manual in CD - ROM or not, they do show up used here and there regularly, the good thing is : most will be dirty / dog eared / greasy so the "serious collectors" who lever read anything anyway, won't touch them, allowing you to get a good deal if you bide your time and as after the E-Bat sale is finished with no bids....

Also there are Glenn's, Autobooks, Chilton's and never forget H.B.O.L. :rolleyes:, they're a cheapo crummy shop manual but are very helpful to get up to speed .

In case this is your first German vehicle you should know that German cars require much more touching than do any others .

This doesn't mean repairs per se, it means they like to be looked over and checked on a regular basis, 90 + % of the time a simple thing may need a quick adjustment or whatever, basic tools are the norm so don't be scared .

Read up and check on how to get that injection element piston moving again. Or delivery valve working. A light spray of quick start with the glow plugs disabled. Do not neglect to do this.


Should get it running. Todays quick start has a lot less either in it and it has been used to start old diesels forever. Just no glow plugs activating. The block heater on does no harm for the attempt as well. You mist some of the quick start over the intake system. Not going crazy with it.


Personally I would want tp find out if the injection pump can be made to work properly first. If not then what is faced. Remember that this engine is capable of running. It is just not usable with the injection pump as it is.

Diesel Purge. Not as much smoke as I expected.

https://youtu.be/HhoCj5BgnOA

Diesel Purging
 

You need to constantly change the engine RPM's to properly do a Diesel purge ~ best way is to drive it around the neighborhood , under load .

You should also place a clear plastic fuel filter in the return hose so you can see what's being cleaned out.

NAPA/WIX # 33001 or equal .

You're getting there, pretty soon you'll have a nice driver on your hands .

Thanks Nate, I did rev the engine some (not on video) but I will run another can of purge through it once I am able to drive it, but I need to work on the brakes, tires, and tank, plus get a plate before I can drive it on the road.
Since the car sat since 2003, do you recommend cleaning the tank? If so how? Thanks again.

Fuel Tank Cleaning
 

It depends on what comes out when you remove the in tank strainer ~ .

I'm *think* the tank is underneath the trunk floor so I'd prolly remove it and clean / de rust it @ home, not terribly hard to do, you'll need to jack up and safely block the car first .

If you live in an apartment or condo you may have restrictions on your options .

I often place two inline fuel filters before the transfer pump, the first will be a clear plastic screen and the second will be a larger clear plastic paper element one like the WIX/NAPA/ 33001, this after you've removed and gently cleaned the in tank screen .

See what you've got and I'll detail the cleaning, it's a bit messy and will kill the grass so choose your work site carefully .

I recently cleaned and de rusted a 1950's VW fuel tank that had sat since the 1980's, it was rusty and really bad looking inside, no one wanted to touch it after looking in, I cleaned it at home in a few days and it looks _new_ inside, not a speck of rust of crud left .