Recently replaced injectors on my 1983 6.9 IDI, fixed the lope and runs way better but still super hard to start. Needs a lot of ether and some throttle to start, sometimes will start then die immediately still. I've got a return line kit on the way but was checking fuel lines and noticed some replaced lines from the dual tank selector to the injection pump. Could these hose fittings cause air intrusion, and if so how should I go about fitting them to eliminate any chance of air intrusion?



Passenger side

Driver's side


cut lines near selector valve

 

Focus on the fuel lines that are under suction, not pressure.The source is likely to be the pickup screen inside the fuel tank, the tank switch valve, or a bad fitting or fuel line between the tank and the lift pump. First, switch tanks to rule out the fuel pickup. Then splice in a segment clear 3/8,fuel line as a window to detect bubbles. Start at the lift pump and work upstream.

 

simply put, everything i see there cold be causing your issues. zip ties on the line from return cap to filter head?
might as well just leave it open....
and all the hose clamps on suction line splices are not helping matters either.
solid lines without splices...and rubber suction lines are just asking for problems too. the rubber breaks down over time and starts letting air in......if not causes leaks.

 

I'll try this asap, have the clear line already.

This was my feeling as well, got the truck with all those fittings like that. So you'd recommend switching to steel fuel lines between the tank and lift pump w/ compression fittings?

 

yup. eliminate the possible leaks first.
and when you do the return line kit, use hose clamps on the line from #! to filter head. do not put the line from #1 to filter head back on.