Air in Diesel Fuel System

[David M]

Many diesels now come with an electric fuel pump that does the bleeding for you. You might consider installing one.

[witzgall]

What were the temperatures, and do you have fuel with anti-gelling additives?

Chris

[Sandero]

Question from an idiot.

Is it possible to have a self bleeding system... that is one where the air escapes... is forced out if it does get in?

[Charlie]

defjef:
I have a couple of common rail diesel vehicles. They are self bleeding. I don't know how that works but it does. On my boat I have a Yanmar 4JH4E. I installed an electric fuel pump in between the racor filters and the secondary fuel filter. If I have a problem and need to bleed my engine I simply turn it on and most of the time the boat will sputter then start. In the worst cases I have had to turn the pump on and then loosen the bleeding nut that is situated before the injectors. I don't know if it is different with other engines but I imagine it is.

[michaelmrc]

i have considered installing an electric fuel pump bypassing the manual yanmar lift pump but am not sure what type i need to buy.

[tallyhorob]

Originally Posted by michaelmrc

i have considered installing an electric fuel pump bypassing the manual yanmar lift pump but am not sure what type i need to buy.

you don't need to bypass the lift pump, most electoral fuel pumps are add in line to "prime, bleed" the system and can act as a back up if the lift pump fails.

[michaelmrc]

ok so what type should i look at? any brands or suggestions. thanks

[Seahunter]

Yes change the filters. Follow the procedures described in the manual to prime the filters. The lift pump is on the SB side of the engine about mid engine just above the pan level. There you'll find the hand primer. If it's not priming up you may have a faulty lift pump.
I've seen this during rough weather when there's not enough filter coverage (IE at least 2 Racor style filters). Shaking up of diesel will make it foam and will take a few days to level out again. Manual priming of the engine with the lift pump should fix this issue.
Good Luck.

[DRS]

Go to Lordco parts. Theres one at 338 east 2nd just east of Main street. Not far from False creek. Tell them you want an inline diesel fuel pump. I used part number P4389 on my gen set (although its probably not marinized). It came with a mounting bracket. You will need to run 12 volts to it.

[michaelmrc]

Originally Posted by DRS

Go to Lordco parts. Theres one at 338 east 2nd just east of Main street. Not far from False creek. Tell them you want an inline diesel fuel pump. I used part number P4389 on my gen set (although its probably not marinized). It came with a mounting bracket. You will need to run 12 volts to it.

thanks for the part number who's the manufacturer ?

[awpptdt]

First chance that you get install vacuum gages before and after filters and pumps. These will help you pinpoint the exact area to be fixed. Available from Graingers at less than 10 bucks. J.T.Duncan

[Seahunter]

Originally Posted by awpptdt

First chance that you get install vacuum gages before and after filters and pumps. These will help you pinpoint the exact area to be fixed. Available from Graingers at less than 10 bucks. J.T.Duncan

Yes, like JT stated. Sometimes one just assumes others have it all hooked up.

[DRS]

Sorry I just have the part number on the lordco invoice and not the manufatures name

[DeepFrz]

If you install the pump downstream of the filters and want to use it to feed the engine then you should bypass the mechanical pump, or at least install plumbing so that you can bypass the mechanical pump. If you install the electrical pump upstream of your filter, then use it only to fill and prime your system. Its a good idea to install a momentary switch if you install the pump upstream. Racor filters should always be on the low pressure side of the pump. They are not designed to be on the high pressure side.

[ovrmyhead]

Originally Posted by David M

Air in your fuel system is a sign of a vacuum leak between your fuel pump and your fuel tank. It could also be air in your your fuel system from it not being bled thoroughly when you last changed out a filter. Check all the work you have done in the recent past.

If you cannot find the leak then you will need to put a slight pressure on the system and look and listen for fuel or air leaking out.

I have heard this before but dont understand how the air remains. Wont the system push the air out once it is running? I just replaced all my fuel lines and installed an electric fuel pump after the racor and before the fuel pump. I ran the electric to fill the lines then hooked up to the mechanical pump. It cranked over for a minute but started. Will I still have air in my system? If so why doesnt it get pushed out through the return line.