What the heck is this? Extra fuel return?

[6 Nebraska IDIs]

I'm having the same exact problem! Kinda getting annoying when its -5 outside..... Hopefully we can get things figured out

Btw I'm new here and greetings from Northern Utah

Welcome to the club man!
Do you have to tone change problem too?

 

[Rot Box]

Welcome to the club man!
Do you have to tone change problem too?

Thanks and yes I have the tone change problem as well, but only after I capped the line return at the filter head and the front injector.... mabey that was a mistake???

Also I replaced my Schrader valve (that was sticking) with a lockable ball valve on the filter head. If I crack it open after even a few minutes of run time there will be a significant amount of air (while the engine is running) before fuel starts to come out. I just can't for the life of me figure out where the air is coming from

 

[6 Nebraska IDIs]

well a common place is the water separator. But mine's new. So I doubt thats my problem.

 

[Andylad13]

you can have the injectors pressure tested and then you can see if they are bad. and those return lines are probably junk. good luck bud!

 

[fellro86]

Definitely sounds like air intrusion somewhere, if it has a sudden burst of power, then back to normal, that is air. Capping the return line won't cause the tone problem, and if you have the original gray lines, they are 20 years old, surely not going to be in good shape. You need caps and return lines. When you change them, be certain the caps are all the way down, I ran into that, thought they were, but after pushing them down, no more air intrusion troubles. This was right after replacing them. Prior to that, had leaks, as wella s starting troubles. With what I found while replacing them, I was amazed it ran as good as it did.

 

[cleithau]

Do you need to replace both the plastic injector return line cap and the brass fitting on the filter or can you just cap both? My injector return line caps were leaking so I got the kit to replace all the fuel line, caps, and o-rings and once I got it done it leaked still. Could this be the lift pump is supplying to much pressure and it is building up and causing my return line caps to leak?

 

[fellro86]

I just capped the brass fitting and the plastic cap as well. If the caps are still leaking (have to ask) did you replace all the o-rings? Also, did you use any lube to assist in getting the caps on? You may have not gotten the caps all the way down. The lift pump will not overpressure, it is a case of not being sealed. You have to be sure the caps are all the way down, they will leak otherwise.

 

[cleithau]

Replaced all the o-rings, caps, clips and lines. Used oil on the o-rings? Was a cheap aftermarket kit, were there any bad ones? Replaced the o-rings on it again. It leaks less. Wondering now if I got a bad cap. It is just the front drivers side cap that leaks. Also I have an electric lift pump, it builds more pressure than stock, I thought it might be the cause of the leak. What is the return line pressure supposed to be?

 

[cleithau]

yeah its also a source of air entry from dribling return line pia o rings . I simply changed it to a 1/4mp x 3/8 ff 90o elbo also silver brazed sight glasses in oulet of ff line & i/p return. no more bubbles or surprises [a couple of return lines still weep but no more hard starts. hope it helps butch

My line is 5/16th to the IP, can I just eliminate the brass elbow with the hose barb with a 1/4 NPT/5/16 compression fitting? It seems just like the old fitting except the nut with compresses the o-ring around the fuel line won't bottom out.

Is everyone just plugging the barb on the brass fitting on the filter head and the injector return line cap barb with vacuum caps? All I can find all over town is the cheap ones in the variety pack that are thick and black and dry rot in a year or two. I have seen synthetic colored and black caps before but now can't seem to find them when I need them? Anyone have a source where to get them?


Also are the o-rings on the line from the fuel filter to the IP standard o-rings or do they have a formed shape? Mine are so bad they look like crumbled plastic. I'm amazed they weren't leaking.

 

[fellro86]

I just plug a chunk of hose to make a cap if I don't find anything else. If you still have a leak, then you either have a cap that is out of spec, not down on the injector all the way, or damaged o-ring. There should be about 1/16" gap between the plastic cap and the fuel line nut.
I would think the o-rings on the filter housing would be standard size,take the line in with you and fit it accordingly.