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Old 12-09-2015, 12:49 AM   #1
Jrad_150
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Join Date: Sep 2005
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Location: newp cali
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2005 WRX SEDAN

Default 13' WRX 1300cc injectors running lean

I have a 2013 WRX with the following mods.

Tomei EL headers
Tomei 7960
Invidia catless DP
AEM 310lph fuel pump e85 safe
ID 1300CC injectors
Process West Verticooler
Grimmspeed 3 port ebcs

My plan was to tune for 91 and eventually go to flex fuel once Cobb brings their device on the market. I was tuned (Opensourced) by Shawn Church on 91. He had issues throwing fuel at it around 3500rpm that's when the turbo begins spooling. He finally got it drivable and everything was going fine. About a week and a half later I go into full boost in 4 and it's under some good load. I start running was lean. And the problem kept persisting. If I stayed in boost from 1st up I would not have the issue because the turbo would be spooled therefore the fuel would be at max pressure. But it seemed every time under load accelerating from 3k up it will start to run lean and spudder ones it gets past a certain rpm it starts back up with full boost. I just took it back to Shawn today for him to check it out and his data showed I was running 18:1 AFR during that lean rpm range. The car is knock free though. He tried throwing more fuel at it again and it helped turn the fuel pressure on faster once boost hit but it still isn't a linear pull. He was explaining to me since the 1300cc injectors are so big that they are only running at 40% and once boost hits and demands more fuel the ECU can't effectively turn on the fuel pressure quick enough or Downey know how because of the bigger fuel pump as well. He was explaining to me that if I bought a Cobb accessport that he would have an easier time tuning the car because he would be able to change the values of the fuel pump rather than not being able to in Opensource. Does any of this make sense to you guys? I was also wondering if maybe it's my fuel pressure regulator. But if it was the lean rpm range would be consistent in all same scenarios. But the problem only happens with certain throttle position and load on the turbo. I have basically been driving my car in boost just to shift into the next gear.

Let me know what you all think. My plan at the moment is to buy an accessport and let Church throw my car back on the dyno and hopefully the AP will help him dial in my car more precisely.
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Old 12-09-2015, 03:34 AM   #2
bettner12
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Join Date: Feb 2004
Chapter/Region: MAIC
Location: Beaver Falls, PA
Vehicle:
05 LGT 407hp/372tq
Tuned by [email protected]

Default

ECU doesn't control fuel pressure... It does control pump duty cycle, 33%,66% and 100%
But your base fuel pressure is 43.5psi and only rises as the intake manifold becomes pressurized. That is a mechanical system, not electronic.
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Old 12-09-2015, 04:22 AM   #3
jason02wrx
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2016 WRX DGM Limited
2002 WRB/2012 SWP Hatch

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How experienced is this tooooner
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Old 12-09-2015, 06:39 AM   #4
joeleodee
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Is your fuel pump hard wired? Just a thought that I've noticed can be an issue when trying to move this much fuel.
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Old 12-09-2015, 10:30 AM   #5
Jrad_150
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Quote:
Originally Posted by joeleodee View Post
Is your fuel pump hard wired? Just a thought that I've noticed can be an issue when trying to move this much fuel.

No the fuel pump has the stock plug soldered to it. Also I had Oring fitment issues with it on he first attempt to tune it but then I took my car back to prolific and they double oringed the pump after it was fine.
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Old 12-09-2015, 10:31 AM   #6
Jrad_150
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Quote:
Originally Posted by jason02wrx View Post
How experienced is this tooooner

He's very well known! Shawn Church at Church Automotive Testing in Wilmington, California.
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Old 12-09-2015, 10:33 AM   #7
Jrad_150
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2005 WRX SEDAN

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Quote:
Originally Posted by bettner12 View Post
ECU doesn't control fuel pressure... It does control pump duty cycle, 33%,66% and 100%
But your base fuel pressure is 43.5psi and only rises as the intake manifold becomes pressurized. That is a mechanical system, not electronic.

Shawn was telling me about the duty cycle percentages. He was telling me he can change the duty cycle with the accessport. He was saying that the 1300's are just way big and if we were running E85 we wouldn't have an issue because we would be using closer to 60-70% injector duty therefore the pump would raise pressure more easily. ?????
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Old 12-09-2015, 12:54 PM   #8
Jrad_150
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Does anybody else have any input ?
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Old 12-09-2015, 05:38 PM   #9
ShinjiML
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2011 STI
DGM

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Quote:
Originally Posted by Jrad_150 View Post
Shawn was telling me about the duty cycle percentages. He was telling me he can change the duty cycle with the accessport. He was saying that the 1300's are just way big and if we were running E85 we wouldn't have an issue because we would be using closer to 60-70% injector duty therefore the pump would raise pressure more easily. ?????
With the AP, depending on the MY of the car, you can change the threashold of the fuel pump duty cycles based on IPW, IDC, or RPM.

E85 uses much more fuel, which would make the IDCs higher, which would allow the activation of the fuel pump duty cycle to be closer to stock levels, hence removing the need to actually modify the thresholds.
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Old 12-09-2015, 05:47 PM   #10
ShinjiML
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DGM

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Even in RomRaider he can just raise the low and medium fuel pump duty cycle values so that you're getting more fuel, even at low and medium duty levels.

Stock is 33%, 66%, 100%, he could just make it something like 50, 70, 100.

EDIT: reread the first post and realized I had misunderstood what he said. Corrected.

Last edited by ShinjiML; 12-10-2015 at 04:46 PM.
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Old 12-09-2015, 09:16 PM   #11
Jrad_150
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2005 WRX SEDAN

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I just bought an accessport I have my tune next Thursday! Hopefully this issue gets tuned out !

Do you guys think I need a fuel pressure regulator kit?
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Old 12-09-2015, 09:33 PM   #12
jason02wrx
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2016 WRX DGM Limited
2002 WRB/2012 SWP Hatch

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Quote:
Originally Posted by Jrad_150 View Post
I just bought an accessport I have my tune next Thursday! Hopefully this issue gets tuned out !

Do you guys think I need a fuel pressure regulator kit?
I would discuss with another tuner. Just like I never trust one doctor's opinion.

Pick one, send an email and PayPal $20.

I'm sure someone will be willing to help.
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