Hey,

I'm the new owner of a 300d my neighbor gave me after she saw me working on a veggie-oil-fueled bus. As a lover of classic, efficient, eco-friendly transportation (my daily driver's a '70s Schwinn) the new MB fits right into my family.

The lady wanted to be rid of the car because she can't get it to run and neither she nor her husband possess mechanical aptitude. It hasn't run for roughly half a year.

Symptoms were described to me as follows:
*Car was losing power, prefilter was changed. Car ran, losing power for a few weeks, then died.

Here's what I did, so far:
*Tested glow-plugs (they work)
*Bled fuel system at top of spin-on filter & primed per. Haynes manual (clear)
*Cranked engine for 25 sec. durations w/pedal depressed.

No start.

So I cracked the fuel lines @ the injectors and cranked the engine again.
*Fuel squirted out of the no. 3 cyl line.
*Fuel leaked out of the no. 5 cyl line at a pretty good rate.
Having bled these lines, I tightened them and left the other lines open.
*After cranking for 25 sec. durations until the battery was drained, still no fuel @ no. 1, no. 2 or no. 4 injectors.

The prefilter looks dirty, and I'm unsure of the condition of the spin-on filter, so I'm changing those both out next time I'm home from school.

However:

Since fuel is logically coming through the filters if it's making it out the no. 3 and no. 5 lines, I'm thinking there's something wrong with my no. 1, 2 and 4 delivery valves or their associated seals.

Opinions?

I have heard of the delivery valves getting stuck on cars that have been sitting a long time. It would not hurt to pull the delivery valves to make sure they are un stuck. Only remove the delivery valves and springs, DO NOT mess with the two nuts to the side of the delivery valves on the injection pump.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

The pump may not be getting enough fuel or is partially airlocked. Too early to suspect injection pump problems I believe. Since the last owner parked it some time ago for runability problems there is a problem lurking. Remember there is a screen in the tank that is removable and cleanable if the two front fuel filters being changed out do not help.

Air leaking in somewhere is another potential problem.

Another last hopefully logical thought. It is unlikely that if those pump elements actually failed three would do so. They are more or less isolated from each other just sharing a common fuel supply. Now I could visualise one failing easy enough.

It would help to know the year of 300D as there are four engines involved in that US model designation.

If it is a '90-'93 it should self-prime while cranking provided there is no leak where air can enter.

__________________

Gone to the dark side

- Jeff

My understanding is that I will need to purchase new o-rings and crush rings to do this; what is a good, inexpensive source?

I'll test the 'not enough fuel' thesis with a container of diesel and a hose straight to the injection pump. If the injector pump itself is airlocked, how do I bleed it?

I'll test that fuel flows freely from the tank, but I hope this procedure is easier/less stinky than it sounds. If not, I'm saving this procedure for last.

I have a few fuel lines that are suspect. What are the IDs of the different lines?

Thanks for the prompt and helpful replies!
-Joe

Model Year 1982, with hand pump
-Joe

No O-rings on a 617, just crush washers. They are only a few cents at the dealer.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Hey all,

I'm back in town and started work with some fresh ideas. Since #3 and #5 are towards the back of the pump, it seemed likely to me that the pump was drawing some fuel and some air into the pump and distributing fuel to the back cylinders and air to the front ones.

By operating the hand primer with all valves closed, I was able to pressurize the system and isolate a slight fuel leak in the fuel return line. I suspect the engine was drawing some air from this leak. I installed a length of new fuel hose and the system seems good. Battery's dead again so I have some time to think...

1) Is it unusual for fuel to flow out the return lines with such low resistance? I couldn't have generated more than 1 psi with the hand primer.

2) What stops the fuel pump from drawing fuel from the return lines?

3) After purging air from the return lines with the hand primer, what is the fastest way to eliminate air from the rest of the system?

4) Does anyone have a schematic that represents all the fuel hoses and valves?

Thanks in advance,
-Joe

Before the fuel supply exits the Fuel Injection pump by way of the Over Flow Valve. The Over Flow Valve has a spring and a check ball inside and determines the fuel pressure that feeds the Elements/Plungers and Barrels inside of your Fuel Injection Pump.
This means that when you pump on the Hand Primer it sould go up the pressure that the Over Flow Valve is set to and drop off again.
By the way if your Hand Primer has a Hard Plastic knob on it they can be a source of an air leak.
Get spare fuel can with clean Diesel fuel in it and run a longer fuel inlet hose to the can; prime again w/Hand Primer, loosen some of the Injector hard line nuts and bleed out the air again. Try to start and run on the spare fuel can.

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84 300D, 82 Volvo 244Gl Diesel

Thank you! This got all the air bubbles out (with fuel lines cracked). Car starts up and idles/runs great! Some driveability issues/surging, but so far it seems to be transmission-related.

Mine is quite leaky when being used. Is there a part I can upgrade to that isn't prone to air leaks, and can anyone provide me with the part number?

There is a new improved model of hand pump (about $20) I think.
Go to the "Buy Parts" link at the top of the page and call Phil.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386