I just installed the new fuel pump in the cell. Very nice kit with well done instructions. After the install I ran a volume test and got 44 oz. of fuel and what seemed like a lot of air. The cell was full and I purged the system several times and still got what looked to me to be excessive air.

At the track after only 9 laps the fuel cell was pressurized by the air being pumped back into the fuel cell. When I released the check valve quite a bit of pressure had built up.

First is this pressure normal? Never has that happen with the old pump setup

Second, where does all that air come from and how do I or should I stop it?

Last, is there such a thing as too much fuel. No I don't currently have the pressure regulator installed

Thanks in advance for your help

Lee, I don't think that's normal as I haven't seen or heard of any other instances of this occurring. 44oz sounds pretty standard, but not so badly aerated.
I suspect Mike might chime in with some ideas when he reads this...
Denny

I have installed half dozen and when I do a flow test it is just a solid fuel flow. No air. I also run stabuli vent valves just for the reason of pressure build up in the cell. Hot in the south. Heat from engine. Not from pump. With the new pump submerged in fuel it should not get air.So if the line on the pump (clear pastic one in kit) is not cracked or damaged and sealed on both ends there should not be air. If I saw air in my fuel flow I would take it back apart and flow pump and clear hose out of cell to see the problem. I would think it can not be out side of cell you would have leak.

How convenient. I was just about to start a thread regarding the in tank fuel pump.
I'm trying to decide if it is worth doing over the winter. What are the advantages for the in tank pump? I have heard better pickup and safety as a couple. Can it be installed by pulling the seat and fuel cell cover and cell out (i.e. don't have to pull the engine)?

I replaced the fuel cell (1997 vintage) and did the new fuel pump/collector at the same time. All from under the car or inside the cockpit to remove/replace the cell. Engine didn't need to be removed. Instructions have you doing it that method...

I didn't do the flow test yet, but no air once the pump was primed.

No answers but some ideas. If you ever put an electric power steering system into pressure relief the fluid will get bubbles in it. The pressure seperates the air from the fluid. This is why they make noise in pressure relief and why some systems have pressurized caps. I wouldn't think this type of pump could do this but I would check for blockages that may be driving high pressures at the pump (not at the Schrader valve).. First test the output right at the fuel cell out if that doesn't work take the metal cover off the cell and check the pickup. If that doesn't work start looking in the pump. What you are describing shouldn't be happening. Again just ideas, not necessarly good ones, please post the solution when you figure it out.

Could there be a leak before the pump? How full is your cell?

Taking the cell out is definitely easier than taking the engine out...

Lee Spuhler wrote:
First is this pressure normal? Never has that happen with the old pump setup

What pressure are you getting?

Thanks to all for your thoughts.

The cell was full. So I doubt the air comes from there.

The pressure in the cell was about the same you can produce by blowing very hard on the check valve. Releasing it causes about a 5 second hiss.

What is odd to me is that the system is closed. Even if the air was being picked up in the cell, it would just circulate around. To built pressure it would be necessary to add air to the system someplace. As stated above if there was a opening somewhere with the fuel under pressure I would expect fuel to be pushed out, not air sucked in.

The plan is to start at the bulkhead and test my way through the system until I find where the air is getting in, then figure out why.

I'll post what I learn (or not) when I know more.

Thanks again for the info and thoughts

Update

Checked the fuel at the bulk head, the back of the filter and the input into the fuel rail. No air at any of those locations.

Connected to the fuel rail output and lots of air.

After reading the tech bulletin I found on the mid west site I suspect a worn or weak injector. Going to get them cleaned and tested and also check/replace the rings on the fittings to the fuel rail to be sure they are not cracked or worn.