7.3 return line

[tnmike55]

What is the purpose of the return line from the filter housing to the number 1 injector? A lot of people are plugging the filter housing and using a deadend cap at number 1.

I'm not understanding why it's there. It's another source of air intrusion with it in place.

 

[snicklas]

It's there so any air in the filter and before can purge from the filter head and into the return system and eventually back to the tank. If this line is removed, any and all air the is in the filter and before has to be pushed into and through the IP to be purged. Personally, if I were that worried about it, I would put a small check valve in that line and leave it in place.

Yes, it is a place that can allow air intrusion, but if you are having air get into the system from this line, you are more than likely getting air in from other places also.

 

[tnmike55]

Where can you get a check valve that will fit there?

 

[icanfixall]

As already posted.. This allows air to be removed from the fuel filter. Oregon Fuel Injection and Conestoga Diesel Injection both sell this check valve. But know this first before you purchase a valve. Our idi engine fuel systems can be the small or the large return lines so that decides which size valve you need. Look at the color of the return line clamps. the green is the small and the red is the large. This check valve has a spring inside it and allows flow only out of the filter. If air is getting in from this valve its shot and needs replacing.. As posted..you can run without it but you will end up forcing all the air thru the injection pump. My fuel system came this way when I purchased my rig back in 96. I knew nothing of how anything worked..I learned fast.

 

[typ4]

And again, I have 6 years of use on my truck with everything plumbed stock and I have no air intrusion issues.
Just saying a good sealed system will give little trouble.
Then there is the person that told me the seals in the steel lines arent replaceable. And he fought air till someone showed him how to change olives.lol

 

[tnmike55]

Thanks for the help. This is my first IDI. I love the way it runs.

 

[icanfixall]

Thanks for the help. This is my first IDI. I love the way it runs.

You will find someone is online here every minute of every day too wiling to help..