aeration of fuel. Symptoms?

[Ponyracer1]

I'm working on the car in my sig. I had half a tank in it and it was fine. Got to under 1/4 and now it is cutting out and the pump is changing tone. Cruising at part throttle and the car falls on its face, goes totally lean on the a/f then comes back approx a second later. Then does it again in 5-10 seconds. Doesnt seem to follow a set timetable.

Going to stick some more fuel in it to see if that cures it. If that cures it what's the best way to fix?

What is the symptoms of aeration? I'm thinking when the tank gets low the fuel pump is moving so much fuel that it aerates it?

 

[04cobrawhine]

Honestly, if that fixes it, your best bet is to just keep it above a 1/4 tank. Pretty simple and easy fix. Is there some sort of baffle in the tank not doing it's job properly? I'm not familiar with the BBRC fuel system. It an external pump with a sumped tank?

 

[oldmodman]

Filling the tank should cure it.
Aeration produces bubbles. Bubbles compress, fuel doesn't.
Plus, if you are running return having a small amount of fuel in the tank will allow it to be heated up much faster.
Never a good thing.

 

[Ponyracer1]

Ya I put 5 gallons in it and it fixed it. Not sure what's in the tank, ill have to call bbrc's to see what the setup is as far as baffles. The pump is a custom intank setup good to 1500hp. I think it is just a huge pump with a small tank. Ill just keep her full from now on.

 

[Bad Company]

It sounds like the return fitting doesn't have a down tube to the bottom of the tank. You always want to return the fuel to the bottom of the tank. If you have a fitting at the top of the tank dumping the return without a down tube. Then as the fuel level drops in the tank, the splashing fuel from the return causes aeration. Install a down tube inside the tank for the return line to dump at the bottom of the tank below the fuel level and walla no aeration. Just make sure the down tube is dumping the fuel as far away as possible from the pick up point of the pumps this will keep the fuel from short cycling back to the engine and gaining heat quickly.

 

[Ponyracer1]

Thanks for the tips guys. Ill pull it apart the next time I drop the tank.