:cI have rebuilt a 5 cylinder diesel engine in my 1981 300D mercedes. The old injection pump, quit. It had over 300.000 miles, so i rebuilt the engine. Now i can not get much fuel to the injectors. I bought a used pump from a car that was alredy running, but slung a rod. Scatched car, sold off parts. I pulled the vaccum shutoff from top of pump, it was not holding vaccum; and puched the stem down manually. It took awhile for rge fuel to finally come through thge injector lins; even now it is weak. Pulled line from injector, held finger over line, and could hold back the fuel. I bled all lies and pump,and filter. Is the pump real weak,or bad, or am i doing something wrong. I shot alittle,i mean alittle either in brather, engine fired for couple seconds. It seems that i not enough pressure to open up the injecdtors. How can i check this. Any help would gladly be appreciated.

[QUOTE=yagowrong. I shot a little,I mean a little ether in breather, engine fired ( Knocked. ) for couple seconds.......[/QUOTE]

R rekon ya kilt it rite there Bubba......!

There's very little fuel in total for each injection stroke.
Pressure is key.

Remove the #1 element and check valve/spring. Turn motor to #1 BFTDC. (Begin Fuel Top Dead Center. )
Pump manual primer...lot's of fuel should come through. When it stops foaming and solid clear fuel comes out, refit and try cranking it again.
With empty fuel lines to injectors, sometimes 20 seconds or more needed to get solid fuel to injectors.....While the element is out you could check the injection timimg.

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Please do a search here about injection timing and check it.

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'82 300SD - 361K mi - "Blue"

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listen, look, .........and duck.