Air bubbles in fuel filter.

[carguyinok]

Ok, I have been working on my 72 240Z fuel system today. As most of you know I just did a motor swap. With that the fuel line had been left unhooked for a few days. Well I got it all hooked back up today and notice that there are air bubbles along with fuel thats going into the fuel filter. Now its pulling fuel from the tank and keeps the filter full without any fuel leaking back. But it seems that no matter how long I turn the motor over I still get air bubbles from the tank. Is this a normal thing? If not where should I start looking?

No I have not run the motor yet nor have I even tried. I am just taking my time and looking to make sure everything is good before I run it.

Thank you in advance.

[biddljj]

My 240Z always has the fuel filter half full. I have a clear filter inline before the fuel pump.

I am curious as well....

Jay

Not just a Z - zdisease

[Walter Moore]

I had air bubbles in my clear fuel filter that were caused by a small crack in the filter.

I replaced the filter and the air bubbles eventually went away.

[carguyinok]

This is the stock style filter on the inner fender. I can watch the air come up from the main fuel line so it's not a crack in the filter. I did have a crack in the line from the filter to the fuel pump. But that would let the fuel drain back into the tank and empty the filter. I noticed this when I replaced that line and was watching too see if the filter would drain again.

I will take a closer look at the filter case tomorrow. But dont think thats the case.

[Zforce]

Maybe the pick up tube in the tank has a small hole in it,have you looked at it with a full tank of fuel?

[hls30.com]

Maybe the pick up tube in the tank has a small hole in it,have you looked at it with a full tank of fuel?

Could be the pick up tube, more likely the hose, or an issue with the aux pump if your car has one.

For air to get in there from suction, something is not sealed properly...

Will

[carguyinok]

Thank you, I wasnt sure how the tank was set-up inside. I have it at just over a 1/4 tank now. I didnt want a full tank with the odds being so good that I would need to drop it for a cleaning.

[carguyinok]

Just alittle bump seeking help before leaving for the shop today.