Volvo D4-210 bleeding fuel problem help needed

[Teddy]

I have reported in the past that one of my D4s is sometimes reluctant to start (very intermittently).

We came to the conclusion that air was somehow getting into the fuel lines somewhere. I have checked, and as far as I can see, everything is as it should be.
Indeed, when I manually bled the system with the black rubber thing, air would be removed, followed by fuel with bubbles, and then fuel. After closing the bleed valve and pumping, the plunger would go solid as you might expect.

Now, the problem is that using this method, I cannot get any fuel, with or without air to come out. Air comes out on pumping, but no fuel!! However, the engine is starting ok at the moment.
I checked several times after stopping the engine, and I could get no fuel to come out. Surely fuel must be there otherwise the engine would not start.

As a matter of interest (comparison), the other engine, which has no problem (yet) has the same problem bleeding. No fuel comes out on pumping.

Can anybody give me a clue as to what might be going on? Can the manual pump fail? What happens next time I change the fuel filters? Will I be able to get the engine going without pre-bleeding?

 

[spannerman]

I have experienced this many times, a smart thump or two on the plunger button sometimes gets it working as one of the non return valves sticks open so when you say it pumps air it just blows out and in when you pump. There is a modified pump housing if I remember correctly so it could need replacing.

 

[Teddy]

I have experienced this many times, a smart thump or two on the plunger button sometimes gets it working as one of the non return valves sticks open so when you say it pumps air it just blows out and in when you pump. There is a modified pump housing if I remember correctly so it could need replacing.

Thanks for the advice. I will try it out in a few days time.

 

[volvopaul]

One of the valves is stuck , a tap with a hammer on the round part frees i up.

 

[Teddy]

Thanks guys.
As you thought, a couple of taps with my rubber hammer cured my bleeding problem on both engines.

On a different subject, does the dipstick touch the bottom of the sump? The reason I ask is that the red knob came off on one of my engines. I replaced it with superglue, but it stuck firm about 5mm from its correct position. Could that be a problem?