Diesel lines bleeding help

[Sandibar]

So yesterday while underway the engine stalled and wouldnt start again. We managed to sail and use the dinghy OB to get to a good anchorage.
The tank vent was blocked. That is cleared now. I can get airfree flow to the injector pump, but when cranking the engine the actual injector lines just deliver some drops of fuel. There should be a jet/real squirt, right?
Dont know how to bleed the actual injector pump. Does it even make sense to try if I have tried to bleed the actual injector lines (without success)?
So the questions:
Should there be a squirt of fuel from the loosened injector lines while cranking at full throttle?
Do I need to bleed the injector pump separately?
Can the injector pump be damaged from a blocked tank vent?
Attached a pic of the pump(i think), how the hell does one go on to bleed it?
Any ideas appreciated!

[Tkeeth]

Let me first say I am not an expert, I have only done this 3 times.

When I ran mine dry I first had to crack and fill the fuel filter, tighten then prime to the injector pump. My engine seems to take it from there, while others report having to bleed through the pump to the cylinder head. I also have never seen a "squirt", just started once I saw steady liquid. Hopefully a diesel mechanic can offer some help, but I wasn't sure if you were waiting. The three nuts on top of the engine are the next bleed points(right by the towel). just loosen enough to leak.

[socaldmax]

One way of getting fuel to the pump is to slightly pressurize the tank through the vent. 5-10 psi should do it, while having a helper crank the engine over. Both of my diesel vehicles have a primer pump in case of loss of prime, but on my truck I added a lift pump, due to the long distance from the tank to the injection pump. A lot of trucks come with a lift pump, adding a lift pump is a popular modification on the trucks that don't.

You can use a cheap $20 pump mounted low right next to the fuel tank, powered off the ignition switch through a relay. The reason I recommend a pump is that if you spring a leak on a vacuum fuel line, air enters and the engine dies. Obviously, this will only happen when you need the engine, which is the worst time to find out you need to fix it. A pressurized fuel line, even if it springs a leak, will still push fuel and you'll still have a running engine long after a vacuum fuel lined diesel has died.

The other advantage is it's nearly impossible to trace a vacuum leak, since air goes through a smaller crack than fuel will and there is no trace of it to see. If you visually inspect your fuel lines periodically, with a pressurized line you'll see the beginnings of a leak where it's wet at a hose clamp or something and you can fix it before it strands you. It's also very useful for filling a new fuel filter before cranking the engine and injection pump. It basically eliminates the #1 cause of engine stoppage: loss of prime.

[Sandibar]

Thanks tkeeth! The three (there are actually four) nuts on top of the towel are the injector line nuts. I was trying to bleed them, but get hardly any diesel from them when cranking with open throttle. The pump is on the left. Not sure if it makes sense to loosen the nuts on the pump to see if there is any pressure.
If I cant fix it myself, I think we'll limp home with sails and the outboard. A mechanic would need to be brought here drom the mainland I guess.

[DeepFrz]

Sometimes you need to bleed the system more than once to get all the air out. Most HP pumps have bleed points on them. There are many threads about bleeding on the forum.

[DougR]

Your high pressure injection pump is a Bosch VE model or some licensed clone of a VE pump. After you have bled the system up to the pump input you could loosen the return line banjo bolt on the top of the pump and continue pumping the lift pump until the pump housing is full of fuel. Then snug up the banjo bolt, loosen the high pressure injection line nuts at the injectors ( as you have done) and crank the engine with the throttle at full fuel until you see fuel flow at the injectors. Doesn't have to squirt much. Then tighten up the injector line nuts and start the engine.

Running the system with a plugged vent shouldn't hurt it.

DougR

[Tkeeth]

Originally Posted by Sandibar

Thanks tkeeth! The three (there are actually four) nuts on top of the towel are the injector line nuts. I was trying to bleed them, but get hardly any diesel from them when cranking with open throttle. The pump is on the left. Not sure if it makes sense to loosen the nuts on the pump to see if there is any pressure.
If I cant fix it myself, I think we'll limp home with sails and the outboard. A mechanic would need to be brought here drom the mainland I guess.

The first time took me a few hours, last time I ran it out I had it in less than 10 mins. because I knew just how to make it happen on my boat. I do have the electric pump as well, but had to use the bulb to get it to fill the filter. I never started on full throttle either, haven't heard that one.

[Sandero]

<<<< not an expert by a long shot.... I've opened the banjo fittings.... used the "finger pump" under the fuel filter untill bubbles come out and then a continuous flow of diesel and then tightened the banjo fitting.

This may take several attempts... but presumably these are air bubbles which you want to believe will rise to the highest location in the system.... where they can be bled out.

[Sandibar]

Originally Posted by DougR

Your high pressure injection pump is a Bosch VE model or some licensed clone of a VE pump. After you have bled the system up to the pump input you could loosen the return line banjo bolt on the top of the pump and continue pumping the lift pump until the pump housing is full of fuel. Then snug up the banjo bolt, loosen the high pressure injection line nuts at the injectors ( as you have done) and crank the engine with the throttle at full fuel until you see fuel flow at the injectors. Doesn't have to squirt much. Then tighten up the injector line nuts and start the engine.

Running the system with a plugged vent shouldn't hurt it.

DougR

Alright. Is this the banjo bolt? The big one on top of hp pump? Never heard that term.
Will try it out, thanks! Thanks for all advice so far, love the forum.

[Tkeeth]

Originally Posted by Sandibar

Alright. Is this the banjo bolt? The big one on top of hp pump? Never heard that term. Attachment 152791
Will try it out, thanks! Thanks for all advice so far, love the forum.

I can vouch, do whatever Doug says.

[GKJ Texoma]

I hope this helps. I learned something too!

A banjo fitting (also called an internally relieved bolt) comprises a perforated hollow bolt and spherical union for fluid transfer. They are commonly found in automotive fuel, oil and hydraulic systems (e.g.: brakes and clutch). The pipe connected may be either rigid or a flexible hose.

The main advantage of the fitting is in high pressure applications (i.e. more than 50 bar). The name stems from the shape of the fitting, having a large circular section connected to a thinner pipe, generally similar to the shape of a banjo.


Two banjo fittings atop automotive brake calipers. The copper crush washer in the gap between the fitting and body of the caliper completes the seal.
Compared to pipe fittings that are themselves threaded, banjo fittings have the advantage that they do not have to be rotated relative to the host fitting. This avoids risk of damage by twisting the hose when screwing the fitting into place. It also allows the pipe exit direction to be adjusted relative to the fitting, then the bolt tightened independently.

From: https://en.wikipedia.org/wiki/Banjo_fitting

[Captsteve53]

OK, think the fuel bleeding has been well covered!!

BUT no one has mentioned in these situations if your not careful and you have a raw water /heat exchanged engine on or under the water line you have a big risk of back filling your engine with sea water,

If this is your situation close off the raw water intake intake until you get the engine ticking over then immediately open.

What happens is every time you are trying to start the raw water pump is filling the exhaust system with sea water until it backs up into your engine enters through the open valves (now it will be a real issue!)

Cheers Steve.

[Diesel Bill]

Nothing for me to add. DeepFrz and DougR nailed it. Some times you can get it to fire on a couple of cylinders while you have the other 2 cylinder injector lines cracked to bleed out more air. If it catches and fires then snug up the 2 loose injector line nuts and your off to the races. Good luck.

[kentobin]

What make and model engine do you have?

The manual of my Volvo MD17C has a bleeding procedure. There is one screw that has to be loosened for bleeding and I always forget which one it is so I have it noted in case of emergencies.

Adding an electric fuel pump to help with the bleeding is highly recommended.

I added a Walbro. I bought it 8 or 9 years ago. It's a higher end electric fuel pump. I can't remember the price but even on sale it seemed really expensive. These days I see they're selling for well over $100 each. It also doesn't cause any fuel flow problems when turned off after bleeding the fuel system.

As I don't have any experience evaluating different fuel pumps for reliability I decided to get a recommended brand name. imho the thought of having a cheap pump go out when I really need it isn't high on my list of of things to do just to save a few bucks.

[boeing1]

I would not use the banjo fittings for bleeding, due to the fact they might not seal and leak. I would use bleed ports on the HP pump. and engine fuel filter.
just my experience
good point on caution of raw water backing into engine