Welcome to the North American Subaru Impreza Owners Club Tuesday September 2, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 05-21-2013, 12:09 PM   #1
UK_Hicks
Scooby Newbie
 
Member#: 212064
Join Date: May 2009
Location: San Diego, CA
Vehicle:
2006 Impreza STi
WRB

Default 06 STi Fueling Problems

Hi NASIOC Community,

I could use some helpful advice regarding a fueling problem that has come up with my car. First some information about my STi

I have a very clean 2006 with 77k miles, of which ~25k have been stage 2. My long term goal is a new turbo, injectors and a pro-tune.

Modifications:
Cobb AP running Stage 2 OTS ACN91
SPT intake and heat-shield
SPT radiator shroud
Perrin DP
Perrin turbo blanket
Grimmspeed AOS

The problem:

This first happened on a hot day (almost 100 degrees) on the freeway . I was cruising at 80, and when I put my foot on the gas the car initially stumbled. I was able to limp home by applying minimal throttle. Under load the car feels flat, stumbles, and backfires occasionally (at least I believe that is what is happening). I had a local shop work on the car (SAE), and they reported that the fuel pump was bad, so they replaced it with a DeatschWerks DW200 kit.

The issue seemed to be much better, with just the occasional stumble. But just a few drives later the car seemed even worse. I then replaced the O2 and air/fuel sensors, and cleaned the MAF with CRC. No change.

I should also mention that I have seen these CELs: P0171 System too Lean (Bank 1), and P0301-P0303 Cylinder # Misfire Detected.

Took it to Subaru and they are reporting that the fuel pressure regulator needs to be replaced. I was given a long lecture by the master technician on the dangers of an aftermarket fuel pump, which he says he detected due to the increased pressure. Apparently stock OE puts out only 90 psi, and he is detecting a pressure of 110 psi which he says will destroy the stock PR. I put a call into DeatschWerks but I haven't heard back from them. They want to charge me for 7hrs of labor to remove the intake manifold, and replace the FPR. In addition, they say I need to go back to the stock fuel pump (not currently quoted).

Questions:
Should the DeatschWerks be putting out a consistent pressure, or does it and do OE pumps ramp up pressure as you apply load? Is that what the fuel pump duty reading on the Cobb measures?

Is it likely that the DeatschWerks pump put too much pressure on the FPR, and damaged it, and should I consider an after market FPR, or go back to the stock pump and FPR?

7hrs of labor to replace the FPR? Are they over-charging me?

Again my long term goal is a new small turbo with a tune for an increase in power, while maintaining a reliable daily driver.

Thanks, and I appreciate any input.
* Registered users of the site do not see these ads.

Last edited by UK_Hicks; 05-21-2013 at 12:21 PM.
UK_Hicks is offline   Reply With Quote
Old 05-21-2013, 05:13 PM   #2
jaxscuby
Sammo Hung
Moderator
 
Member#: 10613
Join Date: Sep 2001
Chapter/Region: South East
Location: F L O R I D A
Vehicle:
2002 USDM WRX
WRB

Default

never hear of any issues from the mainline tech at my dealership every spouting
out factory fuel pressure regulator only going 90 psi.

had a 255lph on my wrx since 2003 and replaced it in 2011..no issues.
I do believe your fpr is under driver side of intake manifold.

it only takes an hour to take of manifold but they charge based on the service
manuals time..thats how they make money.

tdo5h-18g is nice upgrade or simular turbo, 650cc and tune.
jaxscuby is offline   Reply With Quote
Old 05-21-2013, 05:48 PM   #3
Sypher
Scooby Specialist
 
Member#: 106366
Join Date: Jan 2006
Chapter/Region: MAIC
Location: VA
Vehicle:
2006 WRX
Blue

Default

sounds like a FPR or honestly spark plugs believe it or not
Sypher is offline   Reply With Quote
Old 05-21-2013, 05:48 PM   #4
Sypher
Scooby Specialist
 
Member#: 106366
Join Date: Jan 2006
Chapter/Region: MAIC
Location: VA
Vehicle:
2006 WRX
Blue

Default

Also install a wideband ASAP so you know what your cars doing
Sypher is offline   Reply With Quote
Old 05-21-2013, 05:50 PM   #5
Sypher
Scooby Specialist
 
Member#: 106366
Join Date: Jan 2006
Chapter/Region: MAIC
Location: VA
Vehicle:
2006 WRX
Blue

Default

also your fuel pump is fine if you want an aftermarket one sure go for it, misfire code can be due to bad spark not the FPR. however! your AFR's will change when you change to a new fuel pump slightly from what Ive seen. My previous WRX the owner now actually put in a EVO X fuel pump and I had to change the entire fuel map.
Sypher is offline   Reply With Quote
Old 05-22-2013, 01:59 AM   #6
UK_Hicks
Scooby Newbie
 
Member#: 212064
Join Date: May 2009
Location: San Diego, CA
Vehicle:
2006 Impreza STi
WRB

Default

Thanks for the responses guys. SAE reported that the fuel pump was bad so I already replaced it, and figured I would go with the DeatschWerks. Now I'm dealing with Subaru claiming that the FPR is not operating correctly. Does anyone know if it is possible to replace the FPR without removing the intake manifold? I've tried searching, but I don't see much information on its location etc.
UK_Hicks is offline   Reply With Quote
Old 05-22-2013, 02:31 AM   #7
Harey
Scooby Newbie
 
Member#: 270569
Join Date: Jan 2011
Default

Since you have to replace the FPR no matter what now get an aftermarket one and get some quotes from other shops. This is if you want to go down the path of getting a dyno done to confirm everything is right afterwards.

Or if you want to keep completely standard then get a new OE pump and OE fuel reg.

It really depends on what sort of car enthusiast you are.
Harey is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 11:30 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.