2.0L LNF Performance Tech 260hp and 260 lb-ft of torque Turbocharged tuner version.

Fuel trim issues / Running lean

Thread Tools
 
Search this Thread
 
Old Mar 21, 2018 | 03:21 AM
  #1  
Process's Avatar
Thread Starter
New Member
 
Joined: 09-12-16
Posts: 22
Likes: 0
From: South Carolina
[HELP!] Fuel trim issues / Running lean

Looking for any help for an issue on my LNF.

Car is running lean on acceleration and randomly goes lean at idle. Short term fuel trims are always at least 7-9% positive during acceleration and long term trims are over 10% and will drop sometimes during deceleration. I've noticed a drop in power while in boost as well, but still spools up normally. Clearing the fuel trims result in short term trims being fully pegged at 10%-20% until long terms slowly climb back up.

Modlist:
Dejon intake, dejon hot side piping, ZZP intercooler, and 3 inch turbo back (catless)

Things I've checked/replaced:

New MAF
Both New MAP sensors
New upstream and downstream O2 Sensors
New spark plugs
New VVT Actuator Solenoids
No vaccuum leaks found by using the propane method
Boost leak test has been performed 4 times (found a leaking intercooler end-tank, replacing it did not fix the issue)
Vehicle does not have any exhaust leaks
Fuel pressure (before and after high pressure fuel pump) is in spec and injectors are all firing consistently and at proper pulse widths with no leaks
There is no Knock Retard or bad timing advance
Compression test is in great condition on all 4 cylinders
There are no misfires, DTCs, or otherwise strange symptoms.
The tuner that programmed the custom calibration has confirmed that the tune is not to blame
Charging system and battery tested good
Had a leaking fuel line replaced before this happened, it was spliced in from the center of the car to the fuel tank

Hopefully someone can help me figure this out, thanks!


Any suggestions are welcome and I'll answer every one. Whoever figures this out I'll gladly pay because at this point I'm desperate to fix this. Thanks

Last edited by Process; Mar 31, 2018 at 12:52 AM. Reason: Updated title
Reply
Old Mar 21, 2018 | 07:12 AM
  #2  
NickStarr's Avatar
New Member
 
Joined: 01-15-18
Posts: 35
Likes: 0
From: Guam
The only time my car went lean was cause of my HPFP.
I was in "P0089" low fuel pressure and limp mode.
That's my only opinion, sorry.
Reply
Old Mar 21, 2018 | 10:36 AM
  #3  
umrdyldo's Avatar
Senior Member
iTrader: (1)
 
Joined: 03-06-06
Posts: 11,663
Likes: 65
From: MO
If you are hitting your target pressures and lamda at WOT then I'd suggest retuning the MAF.

You keep saying it's not tune related, but haven't confirmed if retuning the MAF fixes the issue.

As for what has caused this issue, you have done a good job of narrowing things.

If you were really concerned you could always do a compression and leak down test. How do your valves look?
Reply
Old Mar 21, 2018 | 01:03 PM
  #4  
Process's Avatar
Thread Starter
New Member
 
Joined: 09-12-16
Posts: 22
Likes: 0
From: South Carolina
Originally Posted by umrdyldo
If you are hitting your target pressures and lamda at WOT then I'd suggest retuning the MAF.

You keep saying it's not tune related, but haven't confirmed if retuning the MAF fixes the issue.

As for what has caused this issue, you have done a good job of narrowing things.

If you were really concerned you could always do a compression and leak down test. How do your valves look?
Valves were cleaned not too long ago with a new PCV and IM gasket. The car doesn't hit the commanded lambda at WOT. Im tuned for 12.4 and its around 15 so I don't go WOT until this is fixed
Reply
Old Mar 21, 2018 | 02:52 PM
  #5  
ECaulk's Avatar
Senior Member
iTrader: (6)
 
Joined: 07-19-10
Posts: 26,529
Likes: 841
From: Houston, Texas
It's the tune. The LNF stays in closed loop even at WOT, hence why you have a moving STFT and LTFT. Get the MAF dialed in better and watch the trims get closer to 0.

Is the STFT shifting more positive during WOT?
Reply
Old Mar 21, 2018 | 02:55 PM
  #6  
Process's Avatar
Thread Starter
New Member
 
Joined: 09-12-16
Posts: 22
Likes: 0
From: South Carolina
Originally Posted by ECaulk
It's the tune. The LNF stays in closed loop even at WOT, hence why you have a moving STFT and LTFT. Get the MAF dialed in better and watch the trims get closer to 0.

Is the STFT shifting more positive during WOT?
Its fairly positive in vaccum but when I go into boost and WOT its just a bit lean. Im concerned with the normal driving being so damn lean and this is a recent issue so I'm unsure of how the tune is the problem. I've had this same tune for 2 years and am just now having issues within the past few months
Reply
Old Mar 21, 2018 | 03:11 PM
  #7  
ECaulk's Avatar
Senior Member
iTrader: (6)
 
Joined: 07-19-10
Posts: 26,529
Likes: 841
From: Houston, Texas
What pressure did you go to during your boost leak tests? Did you get a leak detector or soapy solution to cover everything and look for bubbles?

If you have hptuners start logging it and try to make an adjustment and see how it reacts.
Reply
Old Mar 21, 2018 | 03:34 PM
  #8  
Process's Avatar
Thread Starter
New Member
 
Joined: 09-12-16
Posts: 22
Likes: 0
From: South Carolina
Originally Posted by ECaulk
What pressure did you go to during your boost leak tests? Did you get a leak detector or soapy solution to cover everything and look for bubbles?

If you have hptuners start logging it and try to make an adjustment and see how it reacts.
I went to 28 PSI, IM tuned for 23 PSI. Sprayed down every connection, coupler, vac line, and the intake manifold
Reply
Old Mar 31, 2018 | 12:53 AM
  #9  
Process's Avatar
Thread Starter
New Member
 
Joined: 09-12-16
Posts: 22
Likes: 0
From: South Carolina
Bump,new info found
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BlackSS/SC
Problems/Service/Maintenance
41
Nov 30, 2011 06:40 PM
synergy91
2.4L LE5 Performance Tech
5
Sep 12, 2010 02:40 AM
Super_SS
Problems/Service/Maintenance
13
Sep 25, 2007 02:56 PM
glockglade
Problems/Service/Maintenance
10
Mar 20, 2006 02:27 AM




All times are GMT -4. The time now is 10:45 AM.