240D Not getting fuel
 

I am working on a 240D 4 Speed that I bought at a towing auction.
It was a non-running impound which had a state inspection sticker that was two months old, meaning it was definitely running and driving two months ago.

The car had a new primary fuel filter but was missing the clear plastic in line filter when I got it.
I just put a plastic filter on and put the fuel feed line into a gallon container of diesel in the engine bay (the fuel tank has a Mercedes locking gas cap for which I have no key).

Next, I tried operating the primer pump, it was the old plastic kind and leaked everywhere.
I then put a black Bosch new style primer on the lift pump and found that the lift pump leaked fuel badly from the bottom, I could not get diesel to fill the in line filter fully.

I replaced the entire lift pump and gasket with one off a running OM617.
I began to prime the system using the hand primer pump and was able to fill the clear in line filter up, I kept pumping the primer even after the filter was full since I figured the fuel system was bone dry.

I then turned the engine over (it did not start as I have no power to the glow plugs).
Then I tried pumping the hand primer some more as I noticed the in line fuel filter was empty, I could no longer get any fuel sucked into the in line fuel filter despite pumping the primer.

I cranked the engine some more and could not get fuel sucked into the filter. What gives?
Did the primer pump and lift pump fail again?
Is there some stuck valve in the fuel system or something?

I do not understand why the primer is not sucking fuel, and why the motor isn't sucking any fuel from cranking.

Fuel connections appear tight and leak free but maybe I am missing something.

Thanks in advance for any help to this situation.
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I didn't see any mention of the year. I am familiar with the 82 and 83 240D's for I've had similar problems. In the fuel system there are three filters. One at the tank (strainer type) which screws into the tank bottom. Second is the replaceable white filter which connects to the lift pump, and the third is the spin on filter just prior to the IP. Fuel flow on this car is by gravity. On mine there is no fuel pumps either inline or tank mounted.

Suspect either bad fuel in tank or blocked strainer.
Suggestion, use a separate container type fuel tank as a test. Connect a fuel line from this container to the lift pump filter. Then connect a separate return line to this same container. Try running the engine using clean fuel. Also, there may be air in the line from the IP to the injectors. Brake open a fuel line at the injector to make sure that as you pump the primer, there is fuel being delivered to the injectors.

Lastly, you mentioned the the glow plugs aren't working. You'll probably need to fix this issue, for the engine won't start without the chambers heated.

Vehicle is a 1982 240D lift/fuel pump is on the side of the injector pump. Does not appear to be clogged tank strainer, I can get fuel from the tank but I'm running off a fuel can anyway, it's a weird issue no idea why it's not sucking fuel via manual primer or lift pump from cranking.

Thanks

You need to be sure about the tank strainer not being clogged.

if you are runnin from separate fuel can the tank is not issue (at least at the moment) but,..you did not prime properly

make sure secondary filter is full of fuel also (manualy fill)
you have to prime the injector lines also by cranking (trapped air)
lift pump can not be primed by cranking
while manually priming lift pump do you hear any noise on IP or in lines?


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Actually, it's by vacuum.

Crack the injector nut on each injector at the injector and continue using the manual priming pump. Retighten your injector nuts starting with #1 as it starts to seep fuel. Continue until you get done with them all.

Should start then

More likely the valves in the lift pump are not sealing at all. The primer pump uses the valves in the lift pump to get fuel on the upstroke and seal on the downstroke.

A good preliminary test is the primer pump should get harder and harder to use until the relief valve on the injection pump opens. This usually makes a kind of squeeling noise.

If this is not happening and the pressure of the strokes is remaining constant. I would rekit the lift pump.

If This car used waste vegetable oil for fuel the odds of a problem in the lift pump existing also increases .

I agree on most of this
 

If the bypass spring is broken, you can not build pressure, and it is difficult to bleed the system.

The valve kit most common to fail is MB# 0000900210
http://www.peachparts.com/shopforum/mercedes-parts-reference-library/327357-0000900210-om615-616-617-lift-pump-valve-kit.html

If these valves do not seal, the primer pump is useless.

If the primer pump is mis-installed = two copper seal rings, one ring not seated or no seal ring = it will suck/pump air, usually failing to prime.

Fuel injection pump starvation with a good lift pump
Fuel injection pump starvation with a good lift pump - PeachParts Mercedes ShopForum

Fuel pressure relief valve adjustment
Fuel pressure relief valve adjustment - PeachParts Mercedes ShopForum

lift pump test
1979 300td -- Can anybody walk me through a lift pump test? - PeachParts Mercedes ShopForum

fuel pressure
fuel pressure - PeachParts Mercedes ShopForum

http://www.peachparts.com/shopforum/diesel-discussion/249082-fuel-pressure.html

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The Piston inside of the Fuel Supply/Lift Pump could also be stuck. Although I don't know enough to say if that would stop the Hand Primer from working.

If you remove the Big Plug that is in the Center of the Fuel supply Lift Pump there should be a Spring behind it and they you should be able to slide out the Piston.

. He is having too much problem getting any fuel flow is why I did not think it was the relief valve. It is possible though but unlikely in his situation.

Anyways if this is his only basic problem it is not that bad. If the valves are remaining open in the lift pump there may be a visable back and forth type of surging in the clear prefilter.

Depending on just how bad those valves are I suppose. With a known good primer pump if you closed off the output hose and could not pretty much stall the primer pump it then has to be the lift pump I believe. Simple tests save money and time.

also very true...I would change probably need to MUST ;)


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