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Discussion Starter · #1 ·
i'm having problems with my cobra twin pump set up in my 04 gt with a hellion 61mm kit set up for blow thru with the hpx slot style meter. we have the voltage table for the cobra selected, and i'm getting 11.8 to the pumps but the fuel pump duty cycle is at 42% at idle.
checked all wiring from fpdm all the way to the pumps and it's fine. so i got a new set of pumps and we're getting the same situation. bumped up the voltage from table and no help there either. now i'm stumped and need some ideas and mabey some things to check to get this duty cycle down. any help is appreciated greatly!

here's the link to my other thread in the 99-04 gt section:
http://www.modularfords.com/showthread.php?p=1320897#post1320897
 

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Discussion Starter · #3 ·
here are the specs on the car.
04 gt stock longblock with the 61mm hellion turbo kit on there. gonna run 8 pounds of boost hopefully. vmp slot style meter with a 3'' tube going into a 75m throttle body. 50mm tial blow off valve.

we have run the fuel line for kinks/bends and it's fine.
blew out all gas from rails to tank, no trash
new fuel filter
new pumps, pprv delete, new hoses and clamps thruoghout the pump/hat assembly
checked all wiring and voltages to the fpdm and hat/pumps, all is good.
voltage table is correct and we tried to up that and it did not help
upped the pressure to 60psi and it held pressure flawlessly, no drop more that 1 psi.
i'm getting 11.8 volts to the pumps if that helps anything here.

these pumps should be more than i need as they flow 260 and i barely will need 200.

someone give me some ideas here, i'm stuck on this one!
 

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I think you have been wasting a ton of time and work on a non existent problem, I have tuned over 4 '00+GT's with cobra hats and they all idle around 40% FPDC.

Which of the duty cycles are you checking, there are two, pegs at 100% and another that is divided by two (50%). If you are talking about the first one then then you have no problem, what does the car do up top? what is the FPDC at WOT @ 6x00???.

If you are not maxing them out, you have no problem.
 

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Discussion Starter · #5 ·
I think you have been wasting a ton of time and work on a non existent problem, I have tuned over 4 '00+GT's with cobra hats and they all idle around 40% FPDC.

Which of the duty cycles are you checking, there are two, pegs at 100% and another that is divided by two (50%). If you are talking about the first one then then you have no problem, what does the car do up top? what is the FPDC at WOT @ 6x00???.

If you are not maxing them out, you have no problem.
checking the 1.0 value, 100%. fuel pump duty cycle is at 100% at 4800 rpm wot. never ran it above 5200 because it started to lean out after 4800.
 

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checking the 1.0 value, 100%. fuel pump duty cycle is at 100% at 4800 rpm wot. never ran it above 5200 because it started to lean out after 4800.
Ok, now I see you have a problem, I would check the FRPS next.

Do you have an external fuel gauge to check?

Once we had a car with a similar problem as yours that was driving us crazy, dumped the gas tank twice to check the pumps, checked lines, filters, everything and we found nothing. Later we found the FRPS was bad, it was not leaking so you couldn't tell by gas smell on the vacuum line (check that) but we found that it wasn't measuring right, like the electronics, not the diaphgram went.

1) While logging in idle, check the FRPS pressure and FPDC, unplug the vacuum, pressure in the logger should stabilize as it was before but FPDC should go up and car should start to feel rich. If you unplug the vaccum and nothing happens, your FRPS is toast.

2) With an external gauge check pressure at idle, if your tune is set at usual 39, you should read about 30-33 in the gauge, if you read 39 or more, your FRPS is toast.

Best of luck.
 

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Discussion Starter · #7 ·
we checked the frps today as well, pulled the vacuum line and watched the wideband go rich. from 14's to the lower 12's.
you think i need to do a wiring upgrade to the pumps with a relay? would that make the pumps pump/flow more?
i'm getting 11.8 to the pumps rite now, but the alt is pushing in the lower 14's. i also think my battery is crapping out on me as well, mabey that would be something hindering me.

thanks for all the help so far. it's hard to get some good answers on most forums.
 

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You could upgrade your wire and your FPDM by one of Zone5's stage II, we have tried them and they DO work, specially if you upgrade your pumps to FGT units, if you stay with cobra's, not that important.

How is your alternator working, how is your battery voltage up top?

Our FRPS was working, but was like out of range, when it said we had 40psi, it wasn't, it was more, we could command more and we would get that commanded pressure, only it was actually more (read with a fuel gauge) so it was actually pushing the fuel system and duty cycle was up (ours was about .600 at idle). FP pegged at 4000, changed the FRPS, got 90% at 6900, 480rwhp at 9psi.
 

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Discussion Starter · #9 ·
i'm gonna do the wiring upgrade with the 30 amp relay and see if i get any luck. i'm also going to check to se how many amps the pumps are drawing and see if they are both running. i know i need a battery so i'm going to get a new battery also. also going to recheck the pressure again.
 

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Discussion Starter · #10 ·
hank everyone for their help and ideas. it is much appreciated!
well, i will do the wiring upgrade just so it's done as a safety precaution.

as far as what solved the problem,

IT WAS THE BATTERY!!!!!!!

i had the optima in there and it has been going dead the last couple weeks even after charging it fully. so i stopped at ford today and got a 04 cobra battery and put it in. made 6 different data log runs pulling to 6000-6500 rpm's thru the gears and never went over 94% duty cycle. it's also rich as hell thru the entire band in all gears looking at the wideband. so i figure the wiring upgrade might drop me some, but i'm good now without it. once it gets into the 90's the voltage rises and stabalizes the duty cycle. feels good going thu the gears with no timing and extra fuel in it! lol can't wait till the tune gets under way! i'm sure it'll be on video and mabey a few runs thru the gears on the closed track we frequent!
 
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