Welcome to the North American Subaru Impreza Owners Club Wednesday April 16, 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 > Engine Management & Tuning

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 08-16-2002, 02:37 PM   #1
zaidallas
Scooby Specialist
 
Member#: 4106
Join Date: Feb 2001
Location: Expected whp/torque at 25 psi : 450
Default #4 leaning out , what to do ?

I'm having a problem with knocking only on cyl. # 4 and the plug looks pretty white . I've known that this particular one like to lean out all the time but since I got 8 injectors I thought this would fix that problem plus the ability to run a smaller injector on the primary and the big ones in the manifold.
The way I understand it is that the fuel bypasses that particular injector with the stock fuel rails .
I have stock fuel rails with stock non-turbo injectors (280's ?) and a custom fuel rail to feed the 4 550's sitting on the manifold.
Any ideas ?
zaidoun
* Registered users of the site do not see these ads.
zaidallas is offline   Reply With Quote
Old 08-17-2002, 02:35 AM   #2
hayscoob
Scooby Specialist
 
Member#: 4544
Join Date: Feb 2001
Location: santa rosa, ca, usa
Vehicle:
2004 STi Aspen White
Bone Stock for now

Default

Have you tried to modify your stock fuel sytem to parallel? This may help.

Paul...
hayscoob is offline   Reply With Quote
Old 08-17-2002, 08:01 PM   #3
Revision
Scooby Guru
 
Member#: 242
Join Date: Sep 1999
Chapter/Region: MWSOC
Location: Carol Stream, IL USA
Vehicle:
MY05 PSM GGA !STOCK
MY99 RS-RIP / MY95 MX-5

Default

What fuel pressures are you running?

Stock fuel injector #4 has a history of stalling (delivers no fuel) when running high fuel pressures.. (I think it was 60-70 psi)
Revision is offline   Reply With Quote
Old 08-18-2002, 04:20 AM   #4
8Complex

Moderator
 
Member#: 922
Join Date: Feb 2000
Chapter/Region: MWSOC
Location: Schaumburg, IL
Vehicle:
04 FXT
Red

Default

Aren't you running an E6K? Go to Options --> Injector trims and increase the fuel to #4.

/me has been doing his Haltech homework

I also suggest you up the #2 slightly and the #1 just a hair as well. Kinda ramp it up... I have a theory about fuel pressures in the stock routed lines that suggests that the further from the regulator you get, the less pressure you have at that injector.

Last edited by 8Complex; 08-18-2002 at 04:39 AM.
8Complex is offline   Reply With Quote
Old 08-18-2002, 11:51 PM   #5
wac
Scooby Specialist
 
Member#: 689
Join Date: Dec 1999
Chapter/Region: NESIC
Location: Lebanon, NH, USA
Vehicle:
2005 Outback 2.5 XT
Champagne Gold Opal

Default

Quote:
I have a theory about fuel pressures in the stock routed lines that suggests that the further from the regulator you get, the less pressure you have at that injector.
So, you're implying that the pressure decreases as you go from the FPR upstream and back to the fuel pump?

Glossing over the strong possibility that it clearly violates the laws of physics (more specifically, fluid dynamics), I'm very interested in how you came up with this theory?
wac is offline   Reply With Quote
Old 08-20-2002, 11:53 PM   #6
zaidallas
Scooby Specialist
 
Member#: 4106
Join Date: Feb 2001
Location: Expected whp/torque at 25 psi : 450
Default

UPDATE .....LOOK :
8Complex : I've already done what you said but it didn't help . I'm going to have to wire up the system in a different way to have sequential fueling and then I can really adjust everything .
Basically I have stock rails with stock injectors and stock lines for the most part. Then I have a "T" from the line from the filter feeding the custom rail feeding the 550's on top of the manifold. The lines for the 550's system are all SS -6 lines with a -8 feed .
I was thinking that the system feeding the 550's is sucking the fuel away from the line feeding my stock rails . So what I did was disconnect the flow to the stock rails and ONLY run the 550's that are fed by the custom billet rail on top of the engine (one rail feeding 4 550's).
Well guess what ??!! #4 STILL ran lean and pings and the plug is white , while #2 is a bit better and #3,1 are nice looking. This outcome is the same when I was running the 8 injectors (stock rails + custom rail ).
So my conclusion is the reason that #4 leans out on stock fuel systems isn't becuase of small lines or bad rails , maybe some runners getting more air than others or some weird reversion effect. Also that's why I don't think that the parallel feed mod or aftermarket fuel rails for the stock injectors will help becasue I've taken the stock fuel system out of the equation but get the same problem.
I say again , my test included using a stock line from the tank to the filter and then - 8 to feed the billet rail and -6 to go to each injector and -6 to return , DIDN'T use the stock fuel system except for the tank-filter line. Fuel pressure doesn't drop and remains constant so pump is supplying well.
These are the conclusions so far and I'm thinking of more ways to test and elliminate the cause !
I'll try to run the 550's alone for now and wire the system for sequential and richen up the #4 and 2, but I really want to know why this crazy thing is happening.
any more ideas ?
zaidoun
zaidallas is offline   Reply With Quote
Old 08-21-2002, 10:49 PM   #7
zaidallas
Scooby Specialist
 
Member#: 4106
Join Date: Feb 2001
Location: Expected whp/torque at 25 psi : 450
Default

Update :
Today I did some more tests including rearranging the fuel lines for the 550's , trying different fuel pressures and checking the valves settings and the outcome was the same : lean # 4 , little richer # 2 (but still lean) and nice #1 , 3 . This was done with the stock rails/injectors bypassed and also stock lines bypassed .
The conclusion I have is that the problem that everyone is having with # 4 leaning and blowing isn't fuel pressure or stock lines , but maybe somthing like bad design for intake manifold or exhaust manifold especially since exhaust gas from #4 , 2 have to travel alot to get to the turbo.
I could be wrong but I don't know what else to think. I've been doing something that no one does which is bypassing the whole stock system to see if the problem goes away but it hasn't. Keeping in mind I have a JDM WRX exhaust manifold and an extrude honed intake manifold and I don't know how these have effected anything . Rigoli runs his stock WRX manifold but I'm sure its heavily modified .
well that's all I got for today , I thought more people would have some input but oh well , my work continues..................
zaidoun
zaidallas is offline   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

Similar Threads
Thread Thread Starter Forum Replies Last Post
intake mani coming out. what to do while it's out? tobylazur Factory 2.0L Turbo Powertrain 10 05-22-2009 11:23 AM
Still trying to figure out what to do about the ECU... Speedwagon Legacy Forum 1 11-16-2007 10:00 AM
Warranty is out, what to do now? Mar48 Factory 2.0L Turbo Powertrain 12 02-14-2006 04:58 PM
Figured out what to do with the rallye 4000's CosmoTheCat North West Impreza Club Forum -- NWIC 8 04-21-2004 06:08 PM
Radio Lights are Burning out- What to do? sub25rs Car Audio, Video & Security 1 09-06-2003 02:21 AM


All times are GMT -4. The time now is 03:16 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.