Air intrusian question????

[quickster]

if your getting air but no visible leak most likely it's up high. Check the filter head, olives ,and the fuel heater. That has o rings in it too. My '91 had that problem a few years ago.

 

[mobilemech]

check the check ball in the filter head, had this cause this condition before. when you air or vacum tested or just got something in it the check ball may be stuck. it is the highest point in the fuel system and will let fuel drain to tank and cause this condition

 

[franklin2]

check the check ball in the filter head, had this cause this condition before. when you air or vacum tested or just got something in it the check ball may be stuck. it is the highest point in the fuel system and will let fuel drain to tank and cause this condition

So there IS a factory check on the incoming fuel side. I thought there was but wasn't sure.

 

[franklin2]

A spring loaded check with a .33 or 1 psi pop pressure would work properly while running and stopped. It's what I use on my truck.

What brand/model number did you use? Sounds like you have to be careful and get the correct one for it to do the job properly. The fall in the return line to the tank would even develop some pressure that would try to overcome the spring pressure.

 

[79jasper]

So there IS a factory check on the incoming fuel side. I thought there was but wasn't sure.

The one I know of is the fitting where the return line connects to the filter.

Sent from my SM-T537R4 using Tapatalk

 

[mobilemech]

The one I know of is the fitting where the return line connects to the filter.

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yep that's the one, if it isn't working your system will drain to tank in a few hrs and cause air intrusion problems. usually it a piece from a olive or from a return cap after return line work.

 

[BDCarrillo]

So there IS a factory check on the incoming fuel side. I thought there was but wasn't sure.

The factory "check valve" is a spring loaded ball that feeds into the return side of things. It's my understanding that it's meant to help air get pushed out through the return side of things. It's on the pressurized/filtered side of the filter head.

What brand/model number did you use? Sounds like you have to be careful and get the correct one for it to do the job properly. The fall in the return line to the tank would even develop some pressure that would try to overcome the spring pressure.

I don't remember, sorry... the ones I got were hose barbed diaphragm (not ball) models... silver aluminum I think. I used mine on the supply side.