AND you need to include a good starter motor and plenty of electricity to it... the speed of the compression is also critical.

Hundreds of strokes of the primer pump in another attempt to bleed the system did not work, nor did I hear any rattle of the check valve. It still wouldn't start. I took out the check valve (pic) and blew into it and it was not leaking and looked clean enough. I pushed on the ball with a wooden stick and there is spring pressure. Not much to go wrong with a ball and spring. This check valve seals pressure from within the IP (pressure from outside the IP opens it). More later.

Edit: I made a boo boo in the last sentence. After looking at the pic and remembering where I poked the check valve ball from (hole at the end of the bolt), I realize it is pressure from within the IP which opens the check valve.

http://i31.photobucket.com/albums/c3...032808_007.jpg

With check valve out, I hooked up a 15 psi pressure gauge in config of pic below and cranked the engine. Pressure slowly builds and went to about 2-3 psi. A little fuel came out from the check valve port on the IP and the engine fired very briefly. I then put the check valve back in and cranked more, pressure went up to about 8 to 10 psi and it fired up!!! More later.


http://i31.photobucket.com/albums/c3...032908_001.jpg

http://s31.photobucket.com/albums/c397/funola/?action=view&current=Photo_032908_001.jpg

Sounds like you are winning the argument. Keep us posted. Jim

she's running!
 

I went back to the car, disconnected the pressure gauge and put back the 3 way banjo and fired her up! It stalled a few times due to air but by feathering the pedal I got the air out and she's back to running normal.

So it was air and my inability to bleed the system. The factory bleed procedure didn't work. I still don't understand why it is so difficult to bleed.

Thanks everyone for the help, especially Brain for telling me it is NOT the IP, which I and the fuel inj shop I was calling for advise was pretty certain of based on everything I tried.

So the turning point was removing the check valve and crank, which got rid of enough air and brought enough fuel into the IP which allowed it to get an itzy-bitzy amount of fuel to the injectors and she fired. .

Hate to be a wet blanket, but you haven't discovered how the air got in there to begin with, as far as I can tell.

These cars have a tank vent that runs to the right rear corner of the car, under the bumper trim. If you pull the plastic liner away on that side of the trunk you can find the vacuum lines that run from the tank to a little "settling" tank and from their to the hole in the right rear corner of the car.

When this thing gets wet with fuel from over filling, typically, the rubber connectors get gooey and they can close off. When that happens you can be driving along and all of the sudden you stall. The engine stalls and won't restart. You can't "prime" the system because it can't pass fuel from the tank to the injection pump. You opened the system which should have made this possibility go away. But, typically when this event occurs it is really difficult to get the fuel filler cap off. And sometimes the fuel level gauge goes nuts.

My point is, I don't see what caused your original problem. So, I would be concerned you will be at the side of the road again, stalled and unable to get going. Jim

Jim, I ran out of fuel, that's how air got in. Come to think of it, when I vaccumed the tank out to replace the leaky hose, there was not much fuel that came out, certainly not more than what I put in. I have not overfilled the tank nor noticed vacuum when removing the fuel cap. I will however check out the tank vent anyway as PM.

Sorry funola, I missed the fact that you ran out of fuel. So, never mind! Jim

Thank you so much Funola for being so generous with your findings and the wonderful imagery to support your narrative.

Now for the tough one.

Can anyone explain a coherent and compelling inspection and procedure so that one can completely qualify a fully functional fuel delivery and the entire bleeding process which will get one there.

I know I am asking alot because even the MB designers have not come up with it.

As an early step perhaps one should ensure the low pressure circuit is air free by repeating Funola's step of breaking the circuit at the IP check valve.

There are hours of wasted time being spent out there because of the absence of what I am calling for.

If no one comes up with something I will take a stab at it myself but I need to do it when I have time to spare and now is not the time.

If you guys try I will edit the contributions and place them in a logical procedural document which will help us all.

Dionysius,
I suggest you start a new thread to ask this... you should get more hits that way ...so better info.... try to make the title catchy.... there IS an ART to this forum stuff.....LOL

To everybody: Edit and reword this to achieve a debugged procedure to start a diesel on those nasty winter mornings......

Would this procedure have achieved everything done above and if not why not?? (The check valve was not the problem and the pressure measurement was nice but perhaps not necessary)

1. Acquire a jar and place circa one inch of diesel fuel in it.

2. Disconnect the cigar hose from the fuel return line to the tank and seal with finger

3. Place the hose end into the fuel in the jar and release finger

4. Using hand primer and/or cranking continue until bubble-free flow sets up

5. Reconnect the cigar hose to the return line

You now should have an air free IP supply line circuit.
You can now confirm this by pumping the primer and listening for the check valve chatter.

The high pressure side priming can now be done by cracking the nuts at the injectors and witnessing air free flow as you crank.

Tighten the nuts as you witness a consistent flow and your engine should now start if the injectors are good, the air supply is valid, and the compression is achieved as a result of adequate crank speed, together with ring valve cylinder sealing, and operational GPs.

I hate to admit how many times I have run one of these out of fuel, but, I have never had the kinds of problems funola experienced. Even my kids have run them out of fuel, and none of them have had the problem. I think there might be something not working right with funola's hand pump. I also don't take the check valve noise as the end all and be all sign that the air is out of the system. I typically operate the pump vigorously after there is a perceptible resistance increase, usually coinciding with the valve chatter, for 50 or more strokes. Also, mine are all manual transmission cars (my W123s) as is funola's. I would have push started the beast after running the hand pump. Jim

I did wonder about the new black hand primer pump ($10 from ********az) whether it provided enough pressure to bleed the system. Do you know what the spec should be? The old white handled pump leaked fuel with every stroke, pretty ridiculous even when fuel was cheap. Does yours do that? I was afraid of running out of fuel if I continued to pumping on it :D that's why I replaced it with the black pump before doing anything else.

Can you describe exactly the procedure you use to bleed the system when you run out of fuel on the 240D? I've tried so many things and can't remember everthing I did, only what finally worked as described in my post above. I want to simulate a run out of fuel condition and try bleeding it again.

Any takers to help me print a procedure to hang in my garage when I have forgotten all of the above:

funola,

If you actually run dry, you have a "special" case. chances are you won't be on level ground and so you will need to put more than a few gallons in the tank to make sure you have covered the outlet port completely. I once had a problem starting parked on a hill and had to roll the car down to a more level spot to get the thing to start, and it was not even on reserve.

But, yes, my hand pump leaks when I operate it. Not profusely so I lose a quart or something significant when I pump it for 10 minutes, but enough to get it all over my hands. The handle is also a user unfriendly device and will rip the skin off your hand if you don't use a rag to protect yourself. It ends up serving double duty - it absorbs most of the leakage and keeps the knurled edge from killing your skin. Yeah, losing a cup or so of fuel is a drag but, really, do you care? Even at $5.00 a gallon, I would estimate you are losing less than a buck's worth. In the grand scheme of things, that buck doesn't stick in my craw as much as being dopey enough to run out of fuel.

I have never not heard the check valve chatter, but sometimes it takes a lot of pumping. If you don't hear it you are not done. That is about the size of that. Once I hear it I keep pumping another 50 or more strokes. And, given mine is a manual, once I get that done if it won't start I prime it some more, and then try push starting it. Get it rolling at a brisk walking pace and drop it in 3rd, with the glow plugs glowing, drop the clutch. Give it a bit of throttle and it should fire right up. I usually attribute problems firing after a venting exercise to the battery running down, so the push starting does the trick. It also usually gets the engine turning fast enough to finish purging air, if there is any left.

Good luck, Jim