Notices
Evo Engine / Turbo / Drivetrain Everything from engine management to the best clutch and flywheel.

Evo 8 Rich Problem at WOT

Thread Tools
 
Search this Thread
 
Old Dec 31, 2014, 07:29 PM
  #1  
Newbie
Thread Starter
 
us_skinny's Avatar
 
Join Date: Jan 2014
Location: wv
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Evo 8 Rich Problem at WOT

I have a 2005 Evo 8 with about 100,000 miles on it. Just recently the car started stuttering/missing with knock at WOT with a really rich AFR between 8-9.8. But the car still idles fine and cruises fine with a AFR around 14.7. As soon as it builds boost even from 3000 the AFR dips below 10 and stays there and starts knocking. I don't even have to go WOT or build boost, just give it about half throttle and the AFRs will go to the low 10s. The car was running just fine before this.

Changed plugs to brand new NGK BPR7ES gapped at 0.024. Didn't help.
Checked for boost leaks and didn't find or hear anything.
Disconnected battery trying to reset fuel trims. Didn't help.

Mods are:
Tephra mod V7
Perrin Intake
Catless Catback Exhaust
AEM 320 Fuel pump
AEM Tru Boost EBC
Innovate LC-1 Wideband

Could I have a sensor, coil pack, or something fuel related going out?
Old Dec 31, 2014, 08:09 PM
  #2  
Account Disabled
 
Htcg06's Avatar
 
Join Date: Nov 2014
Location: Md
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
Boost leak test?
Old Dec 31, 2014, 08:20 PM
  #3  
Newbie
Thread Starter
 
us_skinny's Avatar
 
Join Date: Jan 2014
Location: wv
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Yep, checked for boost leaks and pressured it up to about 18-20 psi. I didn't hear anything but the pressure slowly dropped over a few minutes.
Old Jan 1, 2015, 06:55 PM
  #4  
EvoM Guru
iTrader: (1)
 
LetsGetThisDone's Avatar
 
Join Date: Oct 2013
Location: Las Vegas
Posts: 15,838
Received 1,571 Likes on 1,348 Posts
What about at 25psi? If its tuned, it's makeing more than 18-20psi of boost.
Old Jan 1, 2015, 07:01 PM
  #5  
Newbie
iTrader: (1)
 
Phoenix Red's Avatar
 
Join Date: Feb 2013
Location: Loganville, Ga
Posts: 16
Likes: 0
Received 0 Likes on 0 Posts
Did find out what the issue was?
Old Jan 1, 2015, 07:12 PM
  #6  
Newbie
Thread Starter
 
us_skinny's Avatar
 
Join Date: Jan 2014
Location: wv
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Didn't pressurize it to 25 yet, Ill give that a try tomorrow and report back. The car hasn't been properly tuned yet, so I have been keeping it around stock boost.

Still haven't found the problem, but I have been doing some reading about fuel pressure regulator issues. I wonder if my AEM 320 fuel pump has started out flowing the stock FPR in boost?
Old Jan 1, 2015, 07:45 PM
  #7  
Evolved Member
 
Bhsj13's Avatar
 
Join Date: Oct 2013
Location: United States
Posts: 1,334
Likes: 0
Received 26 Likes on 26 Posts
hmmmm, front o2 sensor going out?
Old Jan 3, 2015, 10:17 AM
  #8  
Newbie
Thread Starter
 
us_skinny's Avatar
 
Join Date: Jan 2014
Location: wv
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Just seen this thread:

https://www.evolutionm.net/forums/ec...i-do-maps.html

I think this may be the same problems that I am having. I just checked lines from the FPR and no gas in them, so I dont think its the FRP but I dont have a fuel gauge or adapters to test it.

Also, I just noticed that my return line has started leaking and dripping at the small rubber hose under the car that connects the hard line from the car to the tank. I wonder if its leaking because of high pressure in the return line?

If my return line is clogged, how would I unclog it?

Last edited by us_skinny; Jan 3, 2015 at 10:20 AM.
Old Jan 3, 2015, 11:17 AM
  #9  
Newbie
 
CtEvoixMR's Avatar
 
Join Date: Aug 2014
Location: connecticut
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
I would hook up a fuel pressure gauge, and go from there, that would help determine if you have a clogged return line. is there a CEL present?
Old Jan 5, 2015, 09:53 AM
  #10  
Newbie
Thread Starter
 
us_skinny's Avatar
 
Join Date: Jan 2014
Location: wv
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
It was definitely a clogged return. I pulled the hose off to see if I could blow through it and hear bubbles at the tank, but I couldn't. Hooked up my air compressor and tried blowing air through it at over 100 psi and couldn't.

Traced the clog back to the hard line that is bolted to the tank, so I bought 2 feet of fuel line and bypassed the hard line and that fixed the problem.

When the pump switched to high voltage, it must have been overrunning the injectors from the buildup in pressure. I need to get a fuel pressure gauge for future reference.
Old Jan 5, 2015, 10:08 AM
  #11  
Evolving Member
iTrader: (3)
 
robbyredneck's Avatar
 
Join Date: Nov 2013
Location: upstate ny
Posts: 293
Received 0 Likes on 0 Posts
i love happy endings
Old Apr 6, 2015, 09:57 PM
  #12  
Newbie
 
lancerevolution's Avatar
 
Join Date: Sep 2013
Location: Riverside, CA
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by us_skinny
It was definitely a clogged return. I pulled the hose off to see if I could blow through it and hear bubbles at the tank, but I couldn't. Hooked up my air compressor and tried blowing air through it at over 100 psi and couldn't.

Traced the clog back to the hard line that is bolted to the tank, so I bought 2 feet of fuel line and bypassed the hard line and that fixed the problem.

When the pump switched to high voltage, it must have been overrunning the injectors from the buildup in pressure. I need to get a fuel pressure gauge for future reference.
Can someone post a picture of the return fuel line I'm having this same issue?
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Carloverx
General Engine Management / Tuning Forum
6
Mar 2, 2020 12:21 PM
Peage
Evo X General
5
Jan 16, 2015 02:10 PM
usernameinuse
Evo Engine / Turbo / Drivetrain
0
Sep 24, 2012 01:12 PM
shadow1
ECU Flash
13
May 27, 2009 08:16 AM
house_of_senate
ECU Flash
6
Oct 3, 2008 09:24 AM



Quick Reply: Evo 8 Rich Problem at WOT



All times are GMT -7. The time now is 09:32 AM.