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Discussion Starter · #1 ·
i have the stock terminator hat and dual pumps in my 04 gt with 42lb injectors and am running the hellion single 61mm turbo kit. having pump problems and need some answers.

thought one pump might be bad with the initial 45% duty cycle at idle and running to 100% by 4800-4900 rpm's. the actual voltage is 11.8, but the voltage from table is set at 7.5 rite now. so i got a set of pumps that work for sure, we tested them each before swapping them out.

so i swapped out the pumps, rechecked all wiring and hoses and everything is good.

now the basics are the pumps are running at 40% duty cycle at idle and at cruising speeds, then max out rite around 4800-4900 rpm's . we have basically no spark in the car rite now (7) and it's commanding the 7.5 volts from table at wot. should the voltage be bumped up here, or are the pumps only supposed to need the 7.5 volts to get enough fuel for this set up? i'm at a stand still here and don't know what needs to be done and hope some of the guru's can chime in and help me get this thing moving. thanks in advance for any help!
 

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Seems low too me. Doesn't a BAP raise the volts to 17?
 

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Discussion Starter · #3 ·
Seems low too me. Doesn't a BAP raise the volts to 17?
i can command more voltage to the pumps, but am currently running the required voltage for the cobra pump set up on a cobra. not sure if it should be bumped up via the tune or not since i have the 2-valve motor with the 4 valve pumps combo. i have 11.8 available rite now to the pumps, and that should be enough to get me where i need to be, it's just the required voltage in the sct software is set at 7.5 volts for wot.

if anyone has a datalog file could they look and see what the voltage from table is and that will help me out tons to have something to compare mine too.
 

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Discussion Starter · #4 ·
i upped the voltage from table and still no luck. puel pump duty cycle is at 42% and should be at 16% from what i've been reading. i have the blow thru set up with the slot style meter in there from vmp tuning. could it be a mass air meter setting causing this? or is something else throwing this duty cycle off bad for some reason?
 

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What is your setup, what kind of number are you putting down? I have a simiar, blow-thru, cobra pumps ,42lbs, novi 2000. I put down 435hp at 6100 rpm. I had enough fuel but my tuner said pressure started to drop off at 5800rpm. Im pretty sure 03/04 cobras are good to 500+ with their stock fuel setup. My tuner recommended a new fuel filter and bigger injectors to help get more fuel. I was wondering why it seems so low though and you seem to be even worse.
 

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Something is wrong. You should not see 40% at idle!! I suspect a leak in the tank. You need to tune the voltage tables too.
 

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Discussion Starter · #7 ·
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.

these pumps should 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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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.

these pumps should 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!
If it works at 60 psi whats the problem?
 

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You have a serious problem if your at 40% duty cycle at idle. There is no way it should be that high. Sounds like a leak in the tank. Thats about the only way I could see the duty cyle being that high. If its not seeing the pressure at the rail then the pumps will pump untill it see's 39 psi. So if its leaking fuel back to the tank somewhere between the pumps and hat, it will keep comanding the pumps faster untill it gets the rail pressure up. That would cause the duty cycle to be up all the time. The only other thing could be a bad FRPS but if you have an aftermarket fuel pressure gauge and its not showing to high of a pressure than i still point toward a tank leak. How hard is your car to start. If it takes a few times to start, id say leak.
 

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Just as a thought, what about that pesky rubber grommet that goes in between the tank and filler neck? That grommet has the tendency to tear, especially in cases where the tank has been lowered several times and/or the neck removed. If it did have a tear in it, it would prevent the tank from being sealed and that "could" cause the PCM to command the pumps to work harder. Since the new pumps were installed, have you filled your tank up all the way?
 

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Discussion Starter · #12 ·
car is 100% duty cycle at 4800 rpm's and leaning out after 4800
starts fine other then the 30 degree night i tried to cold start it. but if above 60 degrees it starts rite up.
the rail pressure is fine, the frps works too. we checked that yesterday.
put all new hoses and clamps on the pump/hat assembly and deleted the pprv while i was at it.
that got me down to 39% duty cycle at idle.

on another note, this optima battery i have has been going dead a lot the last few weeks, so i'm gonna replace that and see if the new battery helps the situation out any. i'm only seeing 11.8 volts to the pumps, so if can get that up it should lower the duty cycle correct? if not i'm gonna do a wiring upgrade and hope that works.
 

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yes. proper voltage to the pumps is very important. I also wonder if your having an alternator problem. It just dosnt seem like your getting the voltage you need. When your at 4800 rpm you should still have at least 12 volts at the FPDM. The less voltage you have, the less fuel available. What voltage are you showing at the pumps when your at 100% duty cycle? It should be close to 12 volts. If its only like 7 or so, you have a charging system problem. Either the battery or the alternator.
 

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Discussion Starter · #14 ·
yes. proper voltage to the pumps is very important. I also wonder if your having an alternator problem. It just dosnt seem like your getting the voltage you need. When your at 4800 rpm you should still have at least 12 volts at the FPDM. The less voltage you have, the less fuel available. What voltage are you showing at the pumps when your at 100% duty cycle? It should be close to 12 volts. If its only like 7 or so, you have a charging system problem. Either the battery or the alternator.
11.8 actual voltage at the pumps.

alt is good, we tested it as well.
 

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Discussion Starter · #15 ·
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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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!
No kidding, really? How'd you figure that out? Was it falling under 13v when running?
 

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Discussion Starter · #19 ·
No kidding, really? How'd you figure that out? Was it falling under 13v when running?
yes, it was maxing out at 10.8 up top. and wasn't pulling enough amps at the pumps. so i took a long shot and changed it out and all is well. finalized the tuning tuesday night and put down 434/527 @ 10lbs boost 17degrees of spark at 6000 rpm

duty cycle is now around 94-95% at full power. going to do the wiring upgrade just to be safe though once the relay comes in.
 
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