Fuel Issue I cant solve??

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Lazerred98cobra

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Hi guys

MY 03 cobra with a 2.8 h mammoth kit works real nice but it has one issue that i just cant cure.. On WOT shifts mostly 3rd to 4th but sometimes 2nd to 3rd the car will fall on its face bigtime... This only happens when i shift and let out of the gas... If i powershift and not lift the car is fine?? Also it has a slight hitch or hesitation when you just pull a little boost to accel but does not do it going WOT??? Im lost and I need any ideas you guys can think of..

I have done plugs, PPRV delete, fuel filter and cleaned the MAF. Gonna try a new FRPS wednesday but is there anything else you guys can think of? Any suggestions would be greatly appreciated.. The car has twin focus pumps and a BAP
 
TORQJNKY

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Just throwing this out there if you have no luck with the FRPS. I wonder if you might have a slightly kinked fuel hose in the tank from your PPRV delete. With the car under WOT and pumps at full capacity, it would stiffen up the rubber fuel line. Once you let off, the hose could slightly kink and cause an interruption in the fuel flow. I don't know if that's the problem, just a thought. Maybe someone else has another idea.
 
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TwinTurbo4vGT

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why are you running focus pumps? sounds to me like you are running out of duty cycle. I would swap them for ford GT pumps and a Dual FPDM kit.
 
xenodragon

xenodragon

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My car had the smae issue...before i removed the PPRV it hesitated between shifts...then we removed the PPRV and it still hesitated between shifts.

Problem was the tuner didnt know what he was doing...got it retuned, and i have zero hesitation
 
TORQJNKY

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CobraStang161 said:
more than likely his one FPDM is going nuts trying to register everything. I think a Dual FPDM kit should be required for something like a 2.8H mammoth.
Click to expand...

Completely agree. OP are you at least running a modified FPDM? I would def look into a Dual FPDM like CobraStang161 mentioned with your set up and even some GT pumps. You will find your FPDS will drop significantly with a dual FPDM harness, have more fuel available and free up more power in your tune. Oh and peace of mind IMO.
 
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TwinTurbo4vGT

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TORQJNKY said:
Completely agree. OP are you at least running a modified FPDM? I would def look into a Dual FPDM like CobraStang161 mentioned with your set up and even some GT pumps. You will find your FPDS will drop significantly with a dual FPDM harness, have more fuel available and free up more power in your tune. Oh and peace of mind IMO.
Click to expand...

definitely. Hell i have a 2.2L with my gt pumps and dual fpdm because i was told a modified FPDM just wouldnt cut it. Let alone a 2.8H

the FPDM kit i got from lethal, its a great kit.
 
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FlaSeaDude

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TORQJNKY said:
Completely agree. OP are you at least running a modified FPDM? I would def look into a Dual FPDM like CobraStang161 mentioned with your set up and even some GT pumps. You will find your FPDS will drop significantly with a dual FPDM harness, have more fuel available and free up more power in your tune. Oh and peace of mind IMO.
Click to expand...

+1 for dual GT pumps, a dual FPDM setup and a Fore billet fuel hat...:beer:
 
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Lazerred98cobra

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ok well Ill take what you guys say to heart here but the car ran fine for over 2 months and this was never an issue and know it has come to a head?? Could the FPDM just randomly start doing this? the car is only running 15lbs and is around 600 rwhp
 
MDK210

MDK210

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i have a simliar issue but one focus pump and BAP. My issue is 2nd-3rd. My tuner was Jon Lund so I'm hoping it wasn't the tune but I will find out this weekend when she gets re-tuned! Everyone always says to run 8 pumps and 32 hats in a return setup thus spending billions of dollars, lol. There almost always a easier solution but it sounds like you are on the correct path. Maybe have a tuner look at it a see what your duty cycle is at WOT, that's my next solution of course after I changed my fuel filter I haven't noticed it again but I haven't hit WOT in awhile either.
 
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Lazerred98cobra

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my duty cycle and fuel pressure drop right off to almost nothing when this happens according to the interceptor gauge in the car... I still think it maybe the FRPS well ill know tommorow night or wed
 
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TwinTurbo4vGT

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Lazerred98cobra said:
my duty cycle and fuel pressure drop right off to almost nothing when this happens according to the interceptor gauge in the car... I still think it maybe the FRPS well ill know tommorow night or wed
Click to expand...

Dude I'm telling you for a fact it's not your frps. Your car wouldn't run if it didn't work. It's the pumps and fpdm I had the same problem when only one of my fpdms were getting voltage
 

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