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Savage 2v
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Discussion Starter #1
Having some issues on the dyno tonight. Recently installed my Dual Cobra pumps and 40A BAP. First thing I noticed after the Cobra pump install...the gauge doesn't read correctly. Second thing today on the dyno, I have a hole in my tank somehow and it leaks when gas goes above a certain point, but im not 100% what point that is.

Now, I have my BAP running full time by having the two wires that go to the hobbs switch twisted together and taped off. All the wiring is right, fused red wire to pink/black wire that goes to the switch, then non-fused to wire that goes towards pumps, and ground of course.

Here's the issue. My tuner ADDED 20% more fuel to the last tune that was on the car to keep it at low 11 AFR's throughout the RPM. Once it hits 5000rpm, it goes WAY lean, like im talking 16:1. The fuel pressure is at a stead 40-45psi all throughout. I'm not sure with the Cobra pumps that I could have a kinked line? When I installed them, it kinda have to press down on the so they would fit in all the way into my GT tank. Before I pressed down for them to fit, it had about 1/4" gap from the hat to the tank. Any help will be great guys.
 

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did you break out the basket in your stock tank? the pumps may be smashed on the bottom limiting fuel flow since the pick up is the lowest part of the fuel hat. also it sounds to me your bap is set right but you exlpained it wrong the non fused end goes to the pink/black wire to the fpdm pin number 9. also large lean spikes that high in the rpm's could be from a pegged maf, but i would think your tuner would know that. your tuner should have seen your fuel pressure fall off if there is is a kink or a restriction of fuel flow
 

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Savage 2v
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Discussion Starter #3
did you break out the basket in your stock tank? the pumps may be smashed on the bottom limiting fuel flow since the pick up is the lowest part of the fuel hat. also it sounds to me your bap is set right but you exlpained it wrong the non fused end goes to the pink/black wire to the fpdm pin number 9. also large lean spikes that high in the rpm's could be from a pegged maf, but i would think your tuner would know that. your tuner should have seen your fuel pressure fall off if there is is a kink or a restriction of fuel flow
Yes basket is out. I couldn't get the like 1/16th inch from the way bottom out, but the rest of it is gone. I'll be dropping the tank there tomorrow to check it all out. The BAP is wired right. I may have worded it wrong. The fused wire says to go to the wire thats only like 2-3" when you cut it (the one coming off the fuel pump shutoff switch). Does 42psi in fuel pressure seem ok? He did a 2001 Saleen the other week and put a 20A bap in with hobbs switch, and it was at 58psi.
 

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it depends how the fuel pressure is read, the delta pressure at 40 psi is fine. an external fuel guage will read around 50-52 psi on 10# of boost.
 

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Savage 2v
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Discussion Starter #5
Yeah it's only made about 9.4lbs at 5100 and 380/396. Guess we'll have to mess with it tomorrow when the tank is dropped again.
 

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The hole could be the grommet to where the filler neck goes into the tank.

As far as the car running really lean seems odd. Theirs plenty of fuel at the rails. So you can basically rule out the pumps and a kinked line. What injectors do you have? And what MAF? Like Stal said, could be the MAF pegging, but the tuner should know that.

Even if one of the pumps failed or whatever, your saying fuel pressure is steady at 40-45, which is at the rails. Maybe one or more of your injectors arent flowing enough?
 

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Savage 2v
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Discussion Starter #8
The hole could be the grommet to where the filler neck goes into the tank.

As far as the car running really lean seems odd. Theirs plenty of fuel at the rails. So you can basically rule out the pumps and a kinked line. What injectors do you have? And what MAF? Like Stal said, could be the MAF pegging, but the tuner should know that.

Even if one of the pumps failed or whatever, your saying fuel pressure is steady at 40-45, which is at the rails. Maybe one or more of your injectors arent flowing enough?
No there is a legit hole at the top of my tank lol. MAF can't be pegged, it's the same PMAS as yours and worked fine last time on the stock motor, same with the injectors. All I changed was the CR to 9:1, LT headers, dual pumps and BAP. I'll be dropping the tank today to see whats going on inside there first.
 

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Savage 2v
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Discussion Starter #9
Decided to just get an 03/04 Cobra tank. Should be here within a week. Should solve the gas gauge issue, definitely fix the leak, and pretty sure it should fix the no fuel after 5k. I'm willing to bet the socks are so far down, the pumps are sucking up the spot where they are at, dry, because they are so far at the bottom.
 

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Good luck man, the only reason why I doubt it was the tank or pumps was because you said their was a steady fuel pressure reading of 40-45psi, and thats reading at the rails. But you never know with these things. Good luck man, keep us updated.
 

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Proud American
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you can have plenty of pressure without volume, and pently of volume without pressure.... simple fluid dynamics and PV= nRT equations.


Sounds like you have the pressure, just not the volume,
 

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How did you get a hole on the top of your tank? After putting in the SVT focus pump my tank had gas pour out of it when I filled it up. The neck filler gromlet was damaged putting the tank back on. Since your pulling the tank anyway you might want to check it.

I can't really help on the rest. Stal and Shaun already covered it.
 

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Savage 2v
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Discussion Starter #13
Good luck man, the only reason why I doubt it was the tank or pumps was because you said their was a steady fuel pressure reading of 40-45psi, and thats reading at the rails. But you never know with these things. Good luck man, keep us updated.
Well yeah, it was steady pressure at the rails, but once we saw it start to go way lean they let off and it wouldn't have been datalogged so we couldn't see the pressure when it went lean. Thanks man.

you can have plenty of pressure without volume, and pently of volume without pressure.... simple fluid dynamics and PV= nRT equations.


Sounds like you have the pressure, just not the volume,
So what are you saying I should upgrade?

How did you get a hole on the top of your tank? After putting in the SVT focus pump my tank had gas pour out of it when I filled it up. The neck filler gromlet was damaged putting the tank back on. Since your pulling the tank anyway you might want to check it.

I can't really help on the rest. Stal and Shaun already covered it.
No idea on the hole, lol might even be just the gasket on the hat.
 

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Well yeah, it was steady pressure at the rails, but once we saw it start to go way lean they let off and it wouldn't have been datalogged so we couldn't see the pressure when it went lean. Thanks man.

Ahhh okay I got yah. I mis understood then. Well hopefully the Cobra tank fixes the issue man. I hope it does. Next time at the dyno, watch the fuel pressure instead of the AFR. See if its starts dropping PSI quick at xxxx rpm.

My pump maxed at 372rwhp, it was down to 29psi @ 6500rpm. But AFR was still at 11.75:1 Which was wierd.

But anyways good luck man, keep us posted. Cant wait to see the results. Record it too
 

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cobra pumps with a 40 amp bap is plenty of pump for most fi setups. mine held out till a little over 600 hp. do you have a wire upgrade done? i know running a relay and a 8 guage wire helped my duty cycle out a little. also get rid of the pprv if you have not already done so.
 

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Savage 2v
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Discussion Starter #16
cobra pumps with a 40 amp bap is plenty of pump for most fi setups. mine held out till a little over 600 hp. do you have a wire upgrade done? i know running a relay and a 8 guage wire helped my duty cycle out a little. also get rid of the pprv if you have not already done so.
No wire upgrade. We're not even at redline yet to see the DC, but I know it wasn't near 100%. PPRV is gone. Pretty sure the pumps are sucking the area the socks are dry and causing it to go way lean in the higher RPM's.
 

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without the basket installed in the tank the pumps should have plenty of fuel to not suck anything dry, unless your real low on gas. getting the cobra tank will deff be a good addition cause with out the baffle you wont be able to go under 1/4 tank of gas with out the risk of fuel sloshing away from the pumps.
 

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The cobra tank is the same as the gt tank except for the cobra having the baffle. The baffle stays at the same level as the rest of the tank. The baffle also only fills from one side. One can still have the fuel sloshed away from the pumps with 1/4 tank in the cobra tank.
Your issues aren't tank related.
 

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Savage 2v
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Discussion Starter #19
The cobra tank is the same as the gt tank except for the cobra having the baffle. The baffle stays at the same level as the rest of the tank. The baffle also only fills from one side. One can still have the fuel sloshed away from the pumps with 1/4 tank in the cobra tank.
Your issues aren't tank related.
I was reading up on another forum and someone else did the Cobra pump swap into a GT tank. Said they didn't fit all the way down so he knocked the stock tank down some with a hammer so the pumps would fit. Pretty sure the Cobra pump setup is taller than the stock GT setup. Either way, it will be an upgrade and I won't have a leak from my stock tank anymore.
 

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Proud American
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see how much volume the pumps are putting out. See how long it takes to fill a quart or a gallon jug. then you can calulate how many GPH its putting out and make sure you have both pressure and volume.
 
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