Where is the return fuel going when it sets up?

[NHBaler]

When my 85 with 6.9 sets up like overnite it will not start unless I bleed it. It does have the electric fuel pump and if you park it down hill it will start. It looks like the return fuel is returning back to the tank,the return lines on the injectors are dry and they was replaced not long ago. Is there a check valve in the system somewhere? Where else should I look for the problem? I don't understand what holds the fuel in the return lines to keep it from going back to the tank,but once it cranks it runs great. Thanks

 

[Exekiel69]

Some times the caps seem like they are tight but they are not seated right, make sure You use vaseline or something when You install them (Mel told Me that and it always works). You can check under the truck on the frame and see if there is any cracked fuel lines, also make sure the fuel filter is tight. Problem is some times You have air but the fuel lines wont leak.

 

[Agnem]

Put a soda straw in your soft drink. Now put your finger over the end of the straw and pull the straw out. It's full of soda eh? Now take your finger off. Oops. You'll need a napkin to clean that up. Your truck isn't holding it's finger over the end very well. Like EZ said, you've got an air leak.

 

[NHBaler]

What is a good trick to finding a air leak when a connection is not wet from fuel?

 

[Exekiel69]

I don't know any tricks for that matter, I start check the fuel lines until I see something wrong. Or You can disconnect the fuel line right before the pump and pump fuel from a bucket, move the pump as close as possible to the fuel filter and that will rule out the fuel lines from the pump, or just check the fuel lines meticulously for cracks or bad connections.

 

[Agnem]

You can temporarily install clear vinyl tubing to find where your leak is. Of course, changing hoses can change everything.