An issue with bubbles in the fuel line.

[RedShadow30]

I have a 1972 charger that sat for 4 years. I have put in all brand new aluminum lines all the way to the tank and put in a new fuel pump and filter as well as completely emptying the tank. I know im not vaporlocking because all the lines are heatsheilded and im sure i have no leaks in the line itself. Im thinking that the strainer in the tank may be clogged and im just getting enough fuel to start it. Originaly when i replaced the pump i got 5.5psi, now i get only 2-3 when first started and within 5-10 minutes it will go 0 and stop. I have replaced the fuel filter twice and i have a clear one so i can see the bubbles when the pressure drops. Am i correct to assume its the strainer in the tank? and can i just drop the tank and clean the strainer or will i have to get a whole new one? I am iching to get this on the road.

 

[lewtot184]

i would think bubbles would indicate sucking air someplace. a clogged sock/strainer wouldn't let anything pass. anyhow, i would drop the tank for an inspection and look closely at hose connections to make sure they're secure.

 

[roadrunnerman]

if you're getting air bubbles showing in you're fuel filter you more than likely have a small hole in your line.let it run for awhile and then shut it off and follow your lines.There should be a wet spot where the fuel is seeping out.

 

[RedShadow30]

I think ill try to get to that this weekend. Crazy weather here in florida so hopefully the weather will thankfully agree. Thank you both.

 

[70sbee]

fuel bubbles

where is your fuel filter located that you are seeing the bubbles in?? make sure your fuel filter is after your pump! because the suction side of the pump really has no pressure and fuel filters never completely fill with fuel (they always have some air in them) you increase the chances of vapor locking a ton! i had my filter between the tank and fuel pump and it would start to spark knock real bad after driving a long ways and whenever it was hot the engine would start very hard! i put the filter on the pressure side of pump and all problems solved! a lot of people say you want to filter the fuel before your pump but the strainer in the tank will filter it fine! good luck!!!!

 

[RedShadow30]

Its after the pump. I have one of those clear ones to see the fuel because I had just reinstalled a manual pump, the previous owner had an electric one on it. Im gonna double check the lines because i had also put brand new aluminum lines all the way back, so im going to make sure that everything is tight and secure. I have no idea why they put an electric one on it, a 6-10 Psi pump is only about 40$ and the carburator is a 750cfm so that shoul be more than enough, I have a 5.5psi min one. The pushrod was fine and the cam is showing no signs of being rounded off either. The fuel filter is about 4 inches after the pump and its vertical.

 

[RedShadow30]

I checked all the lines, it was loose back at the tank! I remember when i put the new lines in i didint finish tightening that one, just enough to hold it. I thank you all tons! After 4 years this thing can finally get back on the road. I would have never thought 3-5 psi could cause a vacuum leak that bad.

 

[Lowhound]

Its sucking air somewhere. Had this problem when I installed a electric Holley pump.Some how it showed good pressure on the pressure gauge. But 1 day as I had someone in the car flipping the switch on & off I noticed a loose fitting, but it only squirted gas as they turned the switch from on to off for just a split second. I would have thought it would have shown a leak with the pump running but it didnt. Snugged it up & problem was gone.

 

[MoparMikey]

Glad you found your problem.
Are aluminum fuel lines safe? I thought alum could crack

 

[RedShadow30]

Well It was driving great and then I vapor locked for real. Got it home, then discovered another vacuum leak in the line. I have a feeling it has something to do with the tank out being a 5/16th and the lines all being 3/8th. Im gonna go create a plan and check list this time.