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Old 04-26-2016, 12:30 PM   #1
BoostinAWD_05
Scooby Newbie
 
Member#: 313035
Join Date: Mar 2012
Chapter/Region: Tri-State
Location: Chesterfield, MI
Vehicle:
2016 WRX STi
Crystal White Pearl

Default Fuel drop at high RPM WOT

Hoping you guys can maybe help me out with a fuel issue I’m having.

Data logging via Cobb Accessport V3. Base fuel pressure set on an Aeromotive 13109 at 50psi without vacuum line 40psi with vacuum line. IAG fuel rails and -6 fuel line kit installed. Series fueling. 1,000cc ID injectors. AEM 320lph drop in fuel pump. 3rd gear pulls from 2500 RPM to 6500 RPM. Max boost around 18psi. Fuel pressure holds steady with a steady increase up to about 5000 RPM at 63psi of fuel. From 5000 to 6500 RPM my fuel pressure drops and I’m losing about 7psi. I’ve taken the fuel pump out and doubled up the o-rings, swapped fuel pumps and checked every fuel connection under the hood with no signs of leaks. Vacuum line on the FPR I have T’d into my bypass valve vacuum and all connections are zip tied.

The regulator as far as I know is the last piece of the puzzle that I haven’t verified. I purchased it brand new about a month ago from a local shop called Oakos Automotive. I dropped off the regulator and they will be sending it back to Aeromotive for a possible warranty. They will bench test it and verify if anything is wrong.

I’m just trying to stay ahead of the curve here… If the regulator checks out to be alright, what else in my system could possibly cause this issue. I’m stuck on a detuned 93 octane map until I can figure this out. Anxiously waiting to pump e85.

Any information will be appreciated.
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Old 04-26-2016, 12:35 PM   #2
BoostinAWD_05
Scooby Newbie
 
Member#: 313035
Join Date: Mar 2012
Chapter/Region: Tri-State
Location: Chesterfield, MI
Vehicle:
2016 WRX STi
Crystal White Pearl

Default

2016 Subaru STI – Full Mod List
• Cobb Stage 3 + Flex Fuel
SF Intake + Air Box
3” downpipe
3” catback
1000cc injectors
AEM 320lph
Fuel pressure sensor kit
Fuel pressure regulator kit <<<< Relocated to T off from bypass valve vacuum instead of manifold. FPR replaced with Aeromotive 13109.
Flex fuel ethanol sensor kit
• Cobb turbo inlet
• Cobb 3-Port boost control solenoid
• IAG Street Series AOS
• IAG TGV delete
• IAG V2 fuel rails <<<< Series fueling
• IAG -6 braided fuel line <<<< Series fueling
• Aeromotive FPR 13109 <<<< Series fueling
• BCP x500 Turbo with GrimmSpeed Wastegate Bracket
• Tial MV-S 38mm wastegate <<<< Spring set up Black & Red; 1 Bar
• Killer B header and EWG uppipe combo
• Killer B oil pickup
• Killer B baffle windage tray
• LIC air pump delete plates
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Old 04-27-2016, 02:37 PM   #3
nysti06
Scooby Newbie
 
Member#: 261347
Join Date: Oct 2010
Chapter/Region: Tri-State
Location: LI, NY
Vehicle:
2006 STI
WRB

Default

im actually having the same problem just swapped in, i just started tuning.
IAG fuel Railes,Lines, ID 1300cc, Aeromotive FPR, Walbaro 450. and as i build boost it leans out. runing at 50PSI, 40PSI unplugged.
im going to check my voltage on the pump, and hopefully a different FPR let me know what you find.
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Old 07-27-2016, 04:51 PM   #4
Coleman84
Scooby Newbie
 
Member#: 399086
Join Date: Aug 2014
Chapter/Region: MWSOC
Location: OHIO
Vehicle:
2012 WRX-sti swap
Pearl white

Default

Quote:
Originally Posted by BoostinAWD_05 View Post
2016 Subaru STI – Full Mod List
• Cobb Stage 3 + Flex Fuel
SF Intake + Air Box
3” downpipe
3” catback
1000cc injectors
AEM 320lph
Fuel pressure sensor kit
Fuel pressure regulator kit <<<< Relocated to T off from bypass valve vacuum instead of manifold. FPR replaced with Aeromotive 13109.
Flex fuel ethanol sensor kit
• Cobb turbo inlet
• Cobb 3-Port boost control solenoid
• IAG Street Series AOS
• IAG TGV delete
• IAG V2 fuel rails <<<< Series fueling
• IAG -6 braided fuel line <<<< Series fueling
• Aeromotive FPR 13109 <<<< Series fueling
• BCP x500 Turbo with GrimmSpeed Wastegate Bracket
• Tial MV-S 38mm wastegate <<<< Spring set up Black & Red; 1 Bar
• Killer B header and EWG uppipe combo
• Killer B oil pickup
• Killer B baffle windage tray
• LIC air pump delete plates
What kind of numbers are you pulling down or expect?
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Old 10-03-2016, 03:02 PM   #5
osvaldopavon
Scooby Newbie
 
Member#: 431332
Join Date: Oct 2015
Default Fuel pressure falling

With my STI 2015 built engine i'm actually having low fuel pressure at high RPM, the regulator is set to 43psi.

The first two runs on the dyno are good but around the third pass the pressure start to fall back from 70psi to 38 and some times to 35 and we have to quit around 6800rpm.

Two new fuel pumps were tested, the regulator is new and working correctly, we also test the voltage at the pump with the engine at 6800rpm it indicates 12.8v. Also connect the pump directly to the battery ant run test, all the same.

What is causing this? we don't now yet. Something is happening between the regulator and the pump and that is getting us crazy and frustrated.

If anyone knows anything that can help us to fix this, please post your comments, will be very appreciated.

Thanks
Osvaldo
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Old 09-16-2019, 10:12 PM   #6
julio6969
Scooby Newbie
 
Member#: 233556
Join Date: Dec 2009
Chapter/Region: HIIC
Location: Honolulu
Vehicle:
08 sti
white

Default

Quote:
Originally Posted by osvaldopavon View Post
With my STI 2015 built engine i'm actually having low fuel pressure at high RPM, the regulator is set to 43psi.

The first two runs on the dyno are good but around the third pass the pressure start to fall back from 70psi to 38 and some times to 35 and we have to quit around 6800rpm.

Two new fuel pumps were tested, the regulator is new and working correctly, we also test the voltage at the pump with the engine at 6800rpm it indicates 12.8v. Also connect the pump directly to the battery ant run test, all the same.

What is causing this? we don't now yet. Something is happening between the regulator and the pump and that is getting us crazy and frustrated.

If anyone knows anything that can help us to fix this, please post your comments, will be very appreciated.

Thanks
Osvaldo
similar issue, you ever find the solution?
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