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Old 09-14-2010, 02:46 AM   #1
cubuff
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Member#: 38345
Join Date: Jun 2003
Location: Littleton, CO
Vehicle:
2004 WRB WRX

Default misfire @ 6500 and above on higher boost

My problem is I have a misfire that seems to be somewhat intermittent, it is load dependent it will miss in 4th at 28psi but not in 3rd with 30+ psi. I have tried changing coil packs, adjusting dwell, timing, fuel etc... Its not in the tune its mechanical or electrical. I have filed down the crank sensor to close the airgap and I have changed plug gaps from big to small with no changes

I have a built ej207
Built version 8 heads w/1mm manley valves, supertech valvetrain, cosworth 278/274 cams
Twinscroll borg warner 91/79
FIC 2150cc injectors
In tank walbro to swirl pot with Fuelab external pump
-8 feed with -6 return
aeromotive fpr
AEM EMS


Compression is good and im waiting to do a leakdown to rule out any headgasket issue. I have a HKS amplifier on the way to try out and new race plugs to try. I am willing to try anything at this point I want to get this car back on the dyno asap without any misfire issues. Im itching to make good power with this car. Any info or help is welcome.

Thanks.
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Old 09-14-2010, 03:47 AM   #2
alcoolaid
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Member#: 134949
Join Date: Dec 2006
Chapter/Region: VIC
Location: Vancouver, BC
Vehicle:
'07 SWP STi
Instagram | arthurlam89

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Not the AEM EMS issue that was occurring a while back?
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Old 09-14-2010, 09:17 AM   #3
robbieshonda
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Member#: 122306
Join Date: Aug 2006
Chapter/Region: South East
Location: On the Dyno NC
Vehicle:
2002 Sti PTE 6262
Interlagos Blue 551/441

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avcs heads? there has been an issue with avcs and ems
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Old 09-14-2010, 12:30 PM   #4
cubuff
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Location: Littleton, CO
Vehicle:
2004 WRB WRX

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Quote:
Originally Posted by robbieshonda View Post
avcs heads? there has been an issue with avcs and ems

I was thinking this also. I have AVCS heads with AVCS cams but the AEM for the WRX doesnt control JDM AVCS. So.... a short answer is AVCS isnt hooked up. My cam sensor is in the same as the WRX on the drivers side front of the head.
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Old 09-14-2010, 03:53 PM   #5
john 1badSTI
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Join Date: Dec 2004
Chapter/Region: MWSOC
Location: grove city ohio
Vehicle:
04 sti 10.51@138.5
on e85@ 30psi--spinning

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I will bet that as soon as you install the amplifier your problem will go away,with bumping up the primary vlotage to the coils you will have a mucher stronger,hotter spark.you are not the first high hp high boost suby that has needed a spark amplifier added.good luck
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Old 09-14-2010, 04:15 PM   #6
cubuff
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2004 WRB WRX

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Quote:
Originally Posted by john 1badSTI View Post
I will bet that as soon as you install the amplifier your problem will go away,with bumping up the primary vlotage to the coils you will have a mucher stronger,hotter spark.you are not the first high hp high boost suby that has needed a spark amplifier added.good luck
I really hope it fixes the problem. I cant wait to try it. e85 probably doesnt help the problem at all either.
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Old 09-14-2010, 04:41 PM   #7
john 1badSTI
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Member#: 77470
Join Date: Dec 2004
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Location: grove city ohio
Vehicle:
04 sti 10.51@138.5
on e85@ 30psi--spinning

Default

Quote:
Originally Posted by cubuff View Post
I really hope it fixes the problem. I cant wait to try it. e85 probably doesnt help the problem at all either.
no it doesn't because of the larger volume of fuel to ignite it will show any weaknesses in the ignition system.I have confidence in saying I am 99% sure the amp box will fix your misfires and you should be able to run a gap of .026-.028 no problem.
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Old 09-14-2010, 04:52 PM   #8
ronzogonzo
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Location: Bartlett,Il
Vehicle:
WRX HTA GT3076R
9cm2 eWG'd It's ALIVE!!

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What is the gap?
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Old 09-14-2010, 06:35 PM   #9
cubuff
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Location: Littleton, CO
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2004 WRB WRX

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Quote:
Originally Posted by ronzogonzo View Post
What is the gap?
.020 is the current gap. I have tried a little smaller and higher.
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Old 09-21-2010, 03:50 PM   #10
sean18337
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Location: NY NJ PA
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2007 STI *SOLD*

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Did the ignition amplifier help??
I’m pretty sure I need one as well… My car does misfire a bit above 7200 RPMs and I already have the plug gap at 18thous
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Old 09-21-2010, 03:57 PM   #11
cubuff
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Location: Littleton, CO
Vehicle:
2004 WRB WRX

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Quote:
Originally Posted by sean18337 View Post
Did the ignition amplifier help??
I’m pretty sure I need one as well… My car does misfire a bit above 7200 RPMs and I already have the plug gap at 18thous

It made a pretty noticeable difference. I believe it solved my problem. misfire in 4th appears to be gone. I did a few pulls to 8500 in 4th and no misfires.
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