Evo 8 stutters and goes lean above 20 psi.All of a sudden. - Page 2 - EvolutionM - Mitsubishi Lancer and Lancer Evolution Community



Evo 8 stutters and goes lean above 20 psi.All of a sudden.

Reply
 
 
 
Thread Tools Search this Thread
Old Jan 20, 2018, 05:15 PM   #16
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Biggiesacks View Post
Is this 91 or e85? If your trims are pulling fuel like you said that would make me think blend change on e85. -11 is pulling alot of fuel, where you able to verify if the ecu was hitting stoich when it was pulling that much fuel? If you change your scaling back to the way it was before compensating for the trims, clear them out by pulling the battery and then testing, does the problem persist?
Well the cars been tuned on speed denaity for months. Then out of nowere i felt this issue and then the check engine light set for fuel trims on same night.

So i adjusted the latency to bring trims closer to 5 percent. Problem still there.

So it still misfires or stutters but it seems to have gotten better. But i may just be lying to my self. Also injectors were cleaned and benched about a month ago.
Offline
 
Reply With Quote
Old Jan 20, 2018, 05:25 PM   #17
Evolved Member
 
Biggiesacks's Avatar
 
Join Date: Aug 2005
Location: The Bay Area
Posts: 2,436
Thanked 121 Times in 116 Posts

Drives: 2011 Evo MR, 2003 Evo

What are your afr's doing durring the pull? Do they look good?
Online
 
Reply With Quote
Old Jan 20, 2018, 05:46 PM   #18
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Biggiesacks View Post
What are your afr's doing durring the pull? Do they look good?
So im doing 2nd gear pulls from around 2500 rpm WIDE OPEN THROTTLE and afrs are in check. Around the time i hear my wastegate 20 psi or so it bucks/misfires/stutters. And afrs spike up lean.

From target 11.5 or so to 12.6 then i let off. Dont wana make a crank window
Offline
 
Reply With Quote
Old Jan 20, 2018, 05:48 PM   #19
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

I would assume a misfire would spike rich because of the unburnt fuel in the exhaust stream but i may be wrong.

I read a thread by razorlab or mrfred with similar issue. His ended up being Cam sensor but i already swapped
Offline
 
Reply With Quote
Old Jan 20, 2018, 05:57 PM   #20
Evolved Member
 
Biggiesacks's Avatar
 
Join Date: Aug 2005
Location: The Bay Area
Posts: 2,436
Thanked 121 Times in 116 Posts

Drives: 2011 Evo MR, 2003 Evo

Yah I agree you would think a Miss fire would spike rich. If it was me I would crank the boost all the way down and try and see how the afr's respond to tuning. That is if I was pretty sure it's not a mechanical issue. You can test that the pump is getting full voltage durring cranking. It should spike full power then drop off a second or two after it starts and stabilizes. Also you should check all your vacuum lines especially the ones going from manifold to valve to fuel pressure regulator
Online
 
Reply With Quote
Old Jan 20, 2018, 06:02 PM   #21
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Biggiesacks View Post
Yah I agree you would think a Miss fire would spike rich. If it was me I would crank the boost all the way down and try and see how the afr's respond to tuning. That is if I was pretty sure it's not a mechanical issue. You can test that the pump is getting full voltage durring cranking. It should spike full power then drop off a second or two after it starts and stabilizes. Also you should check all your vacuum lines especially the ones going from manifold to valve to fuel pressure regulator
All vaccum lines are good and ziptied.
Ill check pump voltage next.

Im almost sure dropping the boost would make it run normal. But what will that point to?
Offline
 
Reply With Quote
Old Jan 20, 2018, 06:08 PM   #22
Evolved Member
 
Biggiesacks's Avatar
 
Join Date: Aug 2005
Location: The Bay Area
Posts: 2,436
Thanked 121 Times in 116 Posts

Drives: 2011 Evo MR, 2003 Evo

I would think it would point to needing more fuel in the higher load cell areas. If you can dial in more fuel and your afr's respond as expected then that's probably all you needed, if however they don't then that would point to a mechanical problem.From a high level though it sounds like you threw a code for running too rich so you pulled fuel, and now your running too lean, so maybe the problem wasn't you where too rich in the first place, but some other issue was throwing off the trims. That was kind of what I was getting at when I asked if you where actually hitting stoich with that -11 trim. I will add that changing injectors scaling/latency will almost for sure call for some retuning of the fuel map
Online
 
Reply With Quote
Old Jan 20, 2018, 06:17 PM   #23
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Biggiesacks View Post
I would think it would point to needing more fuel in the higher load cell areas. If you can dial in more fuel and your afr's respond as expected then that's probably all you needed, if however they don't then that would point to a mechanical problem.From a high level though it sounds like you threw a code for running too rich so you pulled fuel, and now your running too lean, so maybe the problem wasn't you where too rich in the first place, but some other issue was throwing off the trims. That was kind of what I was getting at when I asked if you where actually hitting stoich with that -11 trim. I will add that changing injectors scaling/latency will almost for sure call for some retuning of the fuel map
With the code set it still spiked lean during the sputter.

I also think its mechanical but dont know were else to look. Im gonna try my brothers spollin up cop kit. See if it helps
Offline
 
Reply With Quote
Old Jan 20, 2018, 06:38 PM   #24
Evolved Member
 
Biggiesacks's Avatar
 
Join Date: Aug 2005
Location: The Bay Area
Posts: 2,436
Thanked 121 Times in 116 Posts

Drives: 2011 Evo MR, 2003 Evo

Running rich on idle / cruise and lean under load could be regulator related, as it's suppose to pull some psi under vacuum and add psi with boost
Online
 
Reply With Quote
Old Jan 20, 2018, 07:51 PM   #25
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Biggiesacks View Post
Running rich on idle / cruise and lean under load could be regulator related, as it's suppose to pull some psi under vacuum and add psi with boost
Idle is perfect afr and cruise afr is good also.

I can also part throttle all the way to redline and no sputter and perfect afrs
Offline
 
Reply With Quote
Old Jan 20, 2018, 10:41 PM   #26
Evolving Member
 
Join Date: Oct 2012
Location: Dubai
Posts: 301
Thanked 3 Times in 3 Posts

Drives: 2006 Evo9 MR

Quote:
Originally Posted by 4b11slayer View Post
Idle is perfect afr and cruise afr is good also.

I can also part throttle all the way to redline and no sputter and perfect afrs
It sounds like a pump problem or clogging problem.
I had the same issue before and it turned out to be a bad walbro.

Try swapping pumps.
Offline
 
Reply With Quote
Old Jan 21, 2018, 12:28 AM   #27
Evolved Member
Thread Starter
 
4b11slayer's Avatar
 
Join Date: Nov 2015
Location: Santa Ana
Posts: 1,785
Thanked 81 Times in 81 Posts

Drives: 2004 rs ct9a

Quote:
Originally Posted by Evo9_Dubai View Post
It sounds like a pump problem or clogging problem.
I had the same issue before and it turned out to be a bad walbro.

Try swapping pumps.
Pump has less then 8k miles. But ill try
Offline
 
Reply With Quote
Old Jan 21, 2018, 02:15 AM   #28
Evolving Member
 
Join Date: Oct 2012
Location: Dubai
Posts: 301
Thanked 3 Times in 3 Posts

Drives: 2006 Evo9 MR

Also, I had an evox show the same symptoms, swapped pumps and it didn't fix it. It turned out to be the injector resistor that went bad. Unless you have that deleted, I'd try to swap that.
Offline
 
Reply With Quote
Old Jan 21, 2018, 02:47 AM   #29
Evolved Member
 
Join Date: Mar 2013
Location: in a garage
Posts: 621
Thanked 13 Times in 13 Posts

Drives: Lancer

A misfire causes a lean spike not a rich spike.


So it's misfiring because the AFR isn't right, the logger shows lean afterwards.


Your fuel pressure will be wrong of course......lol.
Offline
 
Reply With Quote
Old Jan 21, 2018, 07:52 AM   #30
Evolved Member
 
Biggiesacks's Avatar
 
Join Date: Aug 2005
Location: The Bay Area
Posts: 2,436
Thanked 121 Times in 116 Posts

Drives: 2011 Evo MR, 2003 Evo

Reason I said rich on idle/cruise is because you said this started with you throwing a code for trims and they where -11 which means the computer is pulling fuel because it was rich under closed loop. When you rescaled though that compensated.
Online
 
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
2006 Evo 9 stuttering? Kody Mills General Engine Management / Tuning Forum 10 May 13, 2017 01:52 AM
Evo 9 stutters when accelerating Heirthos Evo General 10 May 13, 2017 01:49 AM
96530706 Evo 8 mines5 EcuFlash 9 Aug 24, 2016 06:05 AM
WOT stutter and boost leak test edsct9a Evo General 11 Apr 21, 2016 12:31 PM
Built Motor missfire\stutter problems evl gsr Evo Engine / Turbo / Drivetrain 1 Apr 20, 2016 03:30 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -7. The time now is 04:11 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: