[Formulajones]

Lots of other things to take into consideration sizing these pumps.

These pumps are rated free flow, which honestly skews things a bit. So those formulas used with fuel pump ratings are already going to come up with a number that's a bit happy.

Then take into account the frictional losses, fuel traveling through 20 feet of fuel line to get up there, along with all the bends and turns it has to make just diminishes that number even further. Put smaller lines on it and things can become even more complicated.

Not to mention any G-force you'll see at the track, or even spirited street driving that the fuel pump has to overcome.

So if this is a 600hp combo, and you want to run a 255 LPH pump, doing the math at 60 psi of fuel pressure, yes the math says it's border line doable. In actual use it's probably a bit on the light side with all other things considered.

Which is why I stated I generally opt for the next size up on pump for some cushion. The price difference is so small it's not even a consideration.

[gman005]

I removed the gas cap and there was pressure in the tank.

[gman005]

I just ordered the regulator from Amazon.

[Scott65]

Does your tank have 2 vent locations? Mine was equipped with a vent located close to the center of the tank, and another coming from around the fuel pump area. Those tee into a single hose going to a rollover vent valve. Also has a small, 1/4" tube vent for the fill neck.

[gman005]

I have 1 vent on sending unit and one in the tank both going to a t and then to the rollover vent.

[Scott65]

Have you tested the fuel pressure with the gas cap removed? That may offer a clue.

[gman005]

Yes the last time the cap was off.

[Scott65]

Well at least you know it's not primarily a venting issue.

[Formulajones]

Yeah unfortunately it's sounding like you'll need to eliminate that internal regulator and get a good external setup on there, and then see if you need to revisit the return line.

[gman005]

I got the new regulator. Do I need to remove the one in the throttle body or just block off the return?

[Scott65]

I would remove it, and flow through the TB, into the regulator, and return from there. Guarantees pressure at the injectors will be stable. I'm sure there are other ways people have done it.

[gman005]

I would think I should regulate the pressure before it enters the TB?

[JLMounce]

Originally Posted by gman005

I would think I should regulate the pressure before it enters the TB?

No, you want to regulate the pressure after the injectors so you don't induce a holes in a hose effect across the fuel rails.

[Formulajones]

You can do it both ways.

Some like to do it after some do it before.

Doing it after is like JLmounce says, it'll provide more even pressure throughout the fuel rail for the injectors.

Probably how I'd do the one you have since it's not a stealth setup.

I regulate mine before because it's a stealth. They don't come with a regulator to start with and require an external regulator. The idea of that system is to have one fuel line running to the unit.

[gman005]

Ok Ill do it after.

[gman005]

I got the fuel pressure down but still have the same problem.

[Scott65]

Remind us again what is the problem area. I can see you're not in learn mode, but at 103°F it's not supposed to be.

[Formulajones]

Like Scott said, that screen shot in that particular screen looks normal.

103 degrees so learn isn't on yet, AFR looks decent and I think I see 60 psi on your fuel pressure gauge.

Maybe a shot of the other screen that shows closed loop comp percent and commanded AFR etc....might give a clue.

Have you had it warm enough to start learning yet?

[gman005]

Once it hit 160 degrees it does not want to keep running. You have to keep giving it gas and at that point you cant stay in the garage. The car is in the trailer going to get looked at today. If this doesnt work I will put the carb back on.

[lfdsteve]

It’s been a long, long time since I mucked with my Powerjection but at around that temp I believe you would be coming out of the cold idle section going to the main map ( terrible description but think of it as the choke). Did you set your throttle blades per setup and then recalibrate IAC and TPS? Powerjection has a special section just for cold idle.
Sorry if I missed all that didn’t want to scroll too far back.