Vintage Thunderbird Club International

i was on a straight run on the interstate, I was however running a datalog at the time but have not had a chance to delve into that yet,but this should tell me what happened.

upon looking at the data log,im starting to think the fuel is getting aerated from the fuel return line when it gets to 1/4 tank everything in the data log seemed normal.could be causing the pump to cavitate and or overheat.

What kind of improvement did you get in gas mileage? Just curious

im thinking its better for sure, running the a/c which has never really worked but now it does its the same as without running it,for the years that iv had her.

i ended up moving the return line to the bottom of the tank where the original drain plug was,so far it has not shut down again so im thinking aerated fuel was my issue.thought i would post an update.

Thats good to know. How close was your return line to your fuel pickup? Mine is a few inches away. You can see it in my post about the in tank pump. I am wondering if I should address it now before It becomes a hard to diagnose problem later..

i was told as long as the return line is submerged, if your return line is a part of an in tank set up it would be submerged correct?

I used the bulkhead that came with the sniper kit. It comes with a 90 degree fitting and a corrugated tube that runs to the bottom of the tank. I did it a few inches to the right of the sender opening.

is anyone else experiencing fuel tank pressure build up on hot days?iv got a vented cap and also bought another one just to try and i notice that im still getting pressure at the fuel tank,you can hear it hissing after a long run.

Does the Sniper system use a pressure regulator that returns the fuel back to the tank?

yes it does and i was seeing 70 psi on the inline gauge i ordered a new regulator to check this out.

The issue may be that the fuel is heating up when it goes to the engine and the returning hot fuel is causing it to evaporate in the tank. They make fuel coolers for return lines, you can also add a PWM controller for the fuel pump to reduce the amount of fuel returning to the tank. I've seen this get so bad that the fuel in the tank is literally boiling.

pardon my ignorance but what does a pwm stand for?

Pulse Width Modulation

It is basically a pump speed controller that speeds up the pump when you stomp on the throttle and runs the pump more slowly when you are idling. This causes less return flow back to the tank.

ill have to look at those more closely,thanks.