Check my (newbie) thinking on fuel

[mlydon]

Bleed the filters, then the injector pump, then the actual injectors, by loosening the nuts that hold the injector tubes to them, and cranking till fuel comes out. Tighten half, and crank - it should run slow. Tighten the rest up, it should come up to full speed.

[Compass790]

Originally Posted by djousset

Hopefully I'm in the final stretch.... I installed a bulb primer between the racor and the lift pump and was able to bleed the system through the secondary filter. I cleaned everything and put absorbent cloths underneath so I could see if they were any leaks, all dry. I followed the lines up to the injectors and loosened the bleed screw on the return line to the tank, and started pumping again. I noticed no air or fuel coming out of the injector exit line. After a v e r y l o n g time I decided to give the engine a try and it did start but died within 5 to 10 seconds. I went back down and pumped more and the same thing happened. I feel like if I was able to keep squeezing the bulb while I was turning the engine over maybe it would catch and purge itself? Am I on the right track? One person pumping and one turning the engine over?

What mylodon says. Is there a bleed screw on the injector pump? Try loosening that when squeezing bulb.
Sounds to me like you have air in the injection pump now so you have to loosen the injector line nuts at the injector end one at a time whilst cranking the engine. Tighten them up again when they stop blowing bubbles. You only have to loosen the nuts say a 1/4 turn, dont loosen them right off.
Have you read the bleeding instructions in the operators manual if it has them?
Sounds like you are getting closer but did you check the lift pump was actually pumping? It probably is but always pays to check.
Good luck, it's gunna feel good when it roars into life

[Ramona]

Originally Posted by djousset

Hopefully I'm in the final stretch.... I installed a bulb primer between the racor and the lift pump and was able to bleed the system through the secondary filter. I cleaned everything and put absorbent cloths underneath so I could see if they were any leaks, all dry. I followed the lines up to the injectors and loosened the bleed screw on the return line to the tank, and started pumping again. I noticed no air or fuel coming out of the injector exit line. After a v e r y l o n g time I decided to give the engine a try and it did start but died within 5 to 10 seconds. I went back down and pumped more and the same thing happened. I feel like if I was able to keep squeezing the bulb while I was turning the engine over maybe it would catch and purge itself? Am I on the right track? One person pumping and one turning the engine over?

Symtoms of a classic airleak. You will not see diesel leaking out when you have an airleak. The airleak is on the supply side of the bulb. Go back to the Racor top O ring and start there. You may get the engine to start and run in your current configuration but when you shut down it wont restart. Tighten up all the hose clamps and double up if you have rubber hose over copper pipe. Replace any rubber that has gone hard and definitely do not have plastic hose anywhere. The fuel in the Racor needs to be clear too and definitely no bubbles. The racor needs to be in a position where you have good access, can sit alongside and carefully re assemble.

[Ramona]

I should add I had exactly the same problem with my last yacht with a Racor. I would bleed the engine and it would start and run fine. Would restart fine later in the day and be completely trouble free. Couple of days later I would have the no start problem and have to bleed. After the usual internet search I found this was a regular occurrence with the Racor top O ring. I solved it by tossing the Racor in the bin.

[crashley]

To bleed the injectors you need to crack open the high pressure pipes at the injectors the return line is just for injector leakage back to the tank
Bleed through to the injector pump with your hand pump and then crank the engine until you see fuel at the injectors
MAKE sure you don’t flood the engine with raw water whilst trying to start
You can’t push fuel to the injector with your hand pump
Be careful if your lift pump has failed you may fill your sump with fuel

[Stu Jackson]

Maybe not this, but keep it for future reference. Good luck, you're on the right, methodical approach. An electric fuel pump is a very good idea.


Fuel Starvation and The Obscure Check Ball Valve
https://c34.org/bbs/index.php/topic,10681.0.html
and
https://forums.sailboatowners.com/th...l%20Starvation

[Wotname]

Originally Posted by Compass790

What mylodon says. Is there a bleed screw on the injector pump? Try loosening that when squeezing bulb........

Yes there is. Painted red screw inside red circle. Disregard green box. Except the OP's bleed screw won't be painted red - the red paint was my modification (for obvious reasons).

[Compass790]

Originally Posted by Wotname

Yes there is. Painted red screw inside red circle. Disregard green box. Except the OP's bleed screw won't be painted red - the red paint was my modification (for obvious reasons).

Glad you chimed in with a pic Wottie, will help the OP much better than words.


If you spin the engine over decompressed with that red painted screw loose djousset & fuel spurts out of it you can be sure the lift pump is working.

[Wotname]

Originally Posted by Compass790

....
If you spin the engine over decompressed with that red painted screw loose djousset & fuel spurts out of it you can be sure the lift pump is working.

That's a good point!

I don't know if it has already being mentioned upthread but using the decompression levers is a handy way to bleed the fuel line compared to pumping the little lift pump lever by hand.

Assuming you have good start battery fully charged, you can bleed the following way.
Shut off raw water seacock.
Operate the engine stop cable.
Decompress the engine with both decompression levers.
Spin the engine over with the starter motor (thus operating the lift pump via the cam).
Bleed to the engine mounted fuel filter
Bleed to the injection pump (using screw identified above).
Reset the engine stop cable (i.e. to run)
Reset the decompression levers (to normal position).
Open raw water seacock.
Start engine.
Stop engine.
Clean up.
Open wine.

Spinning a decompressed engine with the stater motor doesn't draw too much current but it is good idea to keep the period to say 10 or 15 seconds and check the temperature of the starter motor occasionally. If you can rest your hand on it, it isn't too hot.

[djousset]

@Stujackson: I did check the obscure ball valve (completely by accident while I was trying EVERYTHING). Thanks for the explanation!

@Wotname: I will look for the injector pump, and that screw on my quite old and dirty engine. Sounds like the next logical step.

@Compass790: I tried turning the engine over decompressed but only had the injector bleed screws loosened. Fuel is fine past two filters and the lift pump. Seems to be stalled before or at injectors.

Sounds like the bulb might not be enough to deliver to the injectors? That's the job of the injector pump...which I will go look for and maybe even sail at some point.

Thanks all and stay tuned.

[Compass790]

It's probably stalled at the injection pumpas you have deduced.
You cannot bleed the injectors before you bleed the injector pump. The squeeze bulb in my hands can produce about 15 psi pressure & the lift pump about 5 psi.
The injector requires over 2300 psi to open, that pressure can only be produced by the injection pump if it has no air in it.
You need to get rid of the air starting from the tank end & proceeding all the way to the injector as Wotname described. Ok you have got air free as far as the injection pump. Now you need to bleed at that bleed bolt he picturedt & the injector pipes.
If, after following Wotnames instructions, ( You owe him a gin or 3 as I dragged him away from his 2qm20 project lol) it still doesnt start try loosening the injector pipe nuts 1/4 turn at the injector end whilst cranking the motor decompressed. Tighten them up again when they stop blowing bubbles.
This was mentioned up thread.

You can do this not decompressed but keep all your hair & body parts away from the belts or you risk getting scalped etc as the engine may start although this advice applies to cranking decompressed too.

Good luck

[Wotname]

Originally Posted by djousset

.......
@Compass790: I tried turning the engine over decompressed but only had the injector bleed screws loosened. Fuel is fine past two filters and the lift pump. Seems to be stalled before or at injectors.

..........

Whoa there, back up....

What / where are the injector bleed screws that you loosened. There are no injector bleed screws on a 2GM20F. Maybe it is just a terminology thing but if you have loosened any part of the steel piping between the injection pump and the injectors themselves then the engine won't start until everything is bleed correctly and in order (as mentioned upthread by others).

Look at the picture of a 2GM20, the injection setup is the same as a 2GM20F.

The engine filter and the injection pump bleed screws are shown in red paint. Note, your engine will not have this red paint, I painted mine to make them easy for others to find. But the screws will be there on your engine.

Ensure there is a steady stream of fuel (ie no air bubbles) coming out of the loosened injection pump screw and then retighten.

The high pressure side starts at the unions circled in blue. You never need to touch these but if you have, make sure they are now tight.

Now go to the steel pipe union at the injector (green arrow and star). Loosen this a quarter turn and spin the engine over until fuel start to flow here. It is best to spin the engine decompressed with either the starter motor or the hand crank if you have one. Tighten the union while the fuel is squirting out.

Then do the same with the other injection line union.

Then start the engine and open wine bottle.

[djousset]

Originally Posted by Wotname

Whoa there, back up....

What / where are the injector bleed screws that you loosened. There are no injector bleed screws on a 2GM20F. Maybe it is just a terminology thing but if you have loosened any part of the steel piping between the injection pump and the injectors themselves then the engine won't start until everything is bleed correctly and in order (as mentioned upthread by others).

Look at the picture of a 2GM20, the injection setup is the same as a 2GM20F.

The engine filter and the injection pump bleed screws are shown in red paint. Note, your engine will not have this red paint, I painted mine to make them easy for others to find. But the screws will be there on your engine.

Ensure there is a steady stream of fuel (ie no air bubbles) coming out of the loosened injection pump screw and then retighten.

The high pressure side starts at the unions circled in blue. You never need to touch these but if you have, make sure they are now tight.

Now go to the steel pipe union at the injector (green arrow and star). Loosen this a quarter turn and spin the engine over until fuel start to flow here. It is best to spin the engine decompressed with either the starter motor or the hand crank if you have one. Tighten the union while the fuel is squirting out.

Then do the same with the other injection line union.

Then start the engine and open wine bottle.

Sigh. Thanks for the diagram. I can see a resemblance to my engine, although mine is much older (and much dirtier/rusty). I did successfully bleed the "red" screw at the secondary pump. I have not found the bleed screw at the injection pump but that's on my hit list.

I may or may not have have fiddled with the screws at the high pressure side (blue circle)... I will make sure they are tight.

I definitely loosened the screws at the steel pipe union at the injector, with no air or fuel seen despite lots of bulb squeezing, but I was not turning the engine over.

It's like a game of Where's Waldo. And there will certainly be wine at the end.

Thanks for the guidance. Looking forward (not really) to trying next steps.

[Wotname]

Originally Posted by djousset

.......

I definitely loosened the screws at the steel pipe union at the injector, with no air or fuel seen despite lots of bulb squeezing, but I was not turning the engine over.
..........

Yep, that will be your current problem. Once the high pressure side (green arrow) has been loosened once, you will NEVER get the pressure back up without turning the engine over.

The bulb (and/or lift pump) can ONLY ever get fuel up to the low pressure side of the injection pump.

I think you are on the home turn now, just a short sprint to the finish line.

As soon as you get steady flow of fuel to the low pressure side on the injection pump (red screw), proceed to cracking high side union (green arrow) while turning the engine over.

I'm opening the wine bottle to let it breathe...it won't be long before you will doing the same!

[Wotname]

Another thought - if your 2GM20F is really old, it may not have a bleed screw at the injection pump (although every one I have seen has it). It doesn't matter, you still have to bleed the air out of the low side right to the injection pump. If you can't find the "red" screw, just loosen off the fuel line going into the injection pump until you get a steady flow of fuel there.

The screw is provided to make it easy but you can achieve the same result by loosening the fuel line banjo bolt.