Fuel cell venting issues

civicmindedex79 · Mar 23, 2013

I recently did a little work to the top end of my motor. I am now running FAST fuel rails and a lil oversized injectors. Running a vette filter/regulator combo and Walbro pump. This setup I have been running for aprox 3 years no issues. I did replace the pump and filter when we rebuilt the top end of motor.

We took the buggy out to ride around at HPO the other day and all day it blew gas out of the vent. No matter what the fuel level was. At first of the day I was assuming I had overfilled the fuel tank. This is not the case because by the end of the day I had to refill the fuel tank and it was still doing it. Almost appears it is siphoning it off of the return line into the tank. If you crack open the lid on the cell it immediately drops and clears out the vent. Making me think it is not enough venting for the cell. Is it a bad idea to put an extended tube to the bottom of the tank and returning fuel to below fuel level. Or anymore ideas of why this started all of a sudden with almost no change in fuel set up.

OK long story short:
Same fuel setup except new pump and filter.
Gas being pushed out of the vent while idling or open throttle.
Lack of ventilation or being returned to close to vent hole?
Is it ok to return fuel below fuel level?

Here are some pics to give you an idea of what it looks like and if I can get it to load a short video.

Pics of the rollover valve

Pic of filter I run directly on top of rollover valve

pic of set up of the top of the tank Blue fitting is return and open fitting is vent.

Fuel cell vent

matth_85 · Mar 23, 2013

Did you change the micron count I the pre filter?

Sent from my iPhone while sitting on the crapper

civicmindedex79 · Mar 24, 2013

Not running a pre filter at all. Only running the vette filter after the pump.

fl-krawler · Mar 24, 2013

Unless your vent has a tube that extends down in the fuel cell, I don't see how its possible for it to push fuel out at different fuel levels.. Is there an outside possibility that you hooked the plumbing up backwards, and you have it plumbed with either the pickup or return as the vent? That would cause the problem you are having (or just having the vent extend to the bottom of the tank)

civicmindedex79 · Mar 24, 2013

fl-krawler said:
Unless your vent has a tube that extends down in the fuel cell, I don't see how its possible for it to push fuel out at different fuel levels.. Is there an outside possibility that you hooked the plumbing up backwards, and you have it plumbed with either the pickup or return as the vent? That would cause the problem you are having (or just having the vent extend to the bottom of the tank)

This has been driving me crazy. So I came home this morning and took the top off of the tank. Guess what? You was absolutely correct. The vent was hooked to the side with the tube. My phone alerted me of this reply as I was removing the last nut. I certainly appreciate the help. I had my driveshaft punch a nice hole in my fuel cell a lil while back and somehow it got swapped. Thanks again.