Dual walbros, going lean at 1/2 tank...

[Zazzn]

Hey guys,

I was wondering if other people have a solution to my problem other then sumping the gas tank..... Basically, I need to have over 1/2 tank at all times or I go lean because the injectors don't get fuel.

 

[blazerkd]

If you've got the funds.....which you may because it seems you're making good power:

-6 feed
-8 return
-20 gal fuel safe
-aeromotive a1000 pump

This would put an end to all fuel system issues; but if you don't want to do all this, I know that you can fabricate a better sump while still retaining the factory gas tank and go to inline fuel pumps......such as what Duane is running on his 7m car.

 

[Zazzn]

Nick is that you? Nholden dayton ohio?

Nick it's eric from toronto...

And yes, I really don't want to sump i guess it's just a flaw of the tank then that it can't flow this much?

 

[figgie]

Zazzn

did you do the "charcoal canister" removal mod? Might want to add it back

 

[blazerkd]

No, this is Kris Blazer; also from Dayton, Ohio. I'm on Ohio Supras, and am friends with Nick Holden....

 

[Zazzn]

Figgie, why's that? yeah there is no charcol can it was huge, no space for it with the 4" i have a 1jz charcoal can that I could hook up... Why? I have a VENTED gas cap btw since I blocked the can line. since it's no longer used with my hanger setup.

 

[jdub]

The tank needs to be under positive pressure (2 psi to be exact). It prevents the pump(s) from cavitating. The evap system (charcoal canister) provides that positive pressure and the correct tank relief pressure. Using a vented gas cap defeats all that

 

[tekdeus]

I thought Zazzn's problem was his 647rwhp pulling so hard it's pushing his gas to the back of the tank and starving the pumps?

 

[IJ.]

Shouldn't happen if the pumps are inside the stock plastic baffle box.

 

[jdub]

I thought Zazzn's problem was his 647rwhp pulling so hard it's pushing his gas to the back of the tank and starving the pumps?

Huh? If the pump pick-ups are covered, why would that be an issue? I can see it at really low tank level, but that would cause the motor to cut from lack of fuel.

 

[IJ.]

No positive pressure and an undersize vent might make the pumps pull a vacuum in the tank and limit flow...

As for the huge charcoal can just use a JZA70 plastic one they're tiny and can be mounted anywhere.

[thumb]http://ij.supramania.com/meth06.jpg[/thumb]

 

[BlackDevilSupra]

Eric,
What have you done with the original fuel EVAP line?

 

[Evilempire1.3JZ-GTE]

Leave the OEM Evap setup alone it is fine & I also use the JZA70 carbon canister its mounted on the bracket to the brake booster 10 mm bolt & uses the OEM evap line.

Fuel return I use the oem fuel feed + the oem fuel return line I use a Y to run them in parallel to the fuel regulator.

Fuel feed is AN-10 with single aeromotive pump it will do for now until a fuel cell will be fitted.

 

[Zazzn]

I can't remember what I did to the evap line, but I'm sure I cut it way down near the frame because my new hanger didn't have a Evap line. This could be a problem (easy to fix run a new line) but the hanger for the pump could be a prob for getting an evap line in there.

Question, I never had this problem with 1 pump with this setup previously? The pumps should be in the stock pickup area...

You see when i get under 1/2 tank I know the pumps are staving because I'm getting no accel, some times when i get in to boost, and espeically if the engine line comes on (tells me it's lean for my AEM)

If I get a non Vented cap I basically need a charcoal can which provides 2 PSI of backpressure in the tank? I know my aristo sounds like opening a pop bottle when you go to fill it up.

 

[IJ.]

2 pumps may be enough to create a vacuum in the tank and this will starve the engine.

Next time it's down to half a tank try taking the cap off and driving it to see if it still leans out.

 

[tekdeus]

Why would it create more vacuum at 1/2 tank than full?

 

[IJ.]

Dunno maybe enough AIR volume by that stage?

The test I posted above will confirm/rule it out and costs nothing to try.

 

[Zazzn]

but ig my cap is vented do you mean it's not venting enough?

 

[supraguru05]

nobody kill me but a option is to put a 2psi residual valve in the vent line from the tank. willwood makes these for disc brake setups but they should work for the fuel vent to. (i know everyone here wants the CC on but for my road race car i dont want nor need that big thing in the engine bay

 

[IJ.]

Did you try the test I suggested?