Lean/rich condition under cruising - LS1TECH - Camaro and Firebird Forum Discussion



PCM Diagnostics & Tuning HP Tuners | Diablo | Pantera EFI
Sponsored by:
Sponsored by:

Lean/rich condition under cruising

Reply
 
Thread Tools Search this Thread
Old 12-06-2017, 01:55 PM   #1
On The Tree
Thread Starter
 
MikeD.'s Avatar
 
Join Date: Mar 2012
Posts: 126
Default Lean/rich condition under cruising

Hey guys, I have kind of an odd situation hoping you can point me in the right direction. I have a 2006 GMC Sierra that I recently swapped an lq9 into, 228/234 cam, CNC/milled 799s, ls2 TB, ls3 injectors and tbss intake.

I brought it too a tuner, whom made it run worse on his tune then it did on a stock tune. Anyway, I decided to roll my sleeves up and try to get it running better on my own. Fast forward a few weeks and the truck runs "well" but not perfect.

My current issue im trying to iron out is a condition where as I enter the freeway, fully warmed up, CL etc, as I begin to come to crusing speed the truck will lean out, o2s will go flat to like 60mv (roughly), and it sit between 16.5-17.0afr, it will seem down on power a bit. This will continue maybe 3/4 minutes of driving. Then I'll feel a change in power, it will pick up in power, then it will be 12.9-13.2 afr, this again will run for 3/4 minutes.

Eventually, the truck begins to "settle" and I'll have a normal 14.6 afr, o2s go back to cycling, and all is well. Now I know it has to do something with the MAF, as SD mode it runs "perfect", gets way better mpg, and afr doesn't fluctuate on the freeway at all, and response as it should.

Again I'm new to tuning and have done my best to research but I haven't come up with much so far? Any suggestions?

I have a log log and my tune, but not sure how to post it from my phone. I can email if someone is will to take a look! Thanks in advance!
MikeD. is offline   Reply With Quote
Old 12-06-2017, 06:46 PM   #2
TECH Fanatic
iTrader: (28)
 
brandon6.0's Avatar
 
Join Date: Dec 2009
Location: Glennville, GA.
Posts: 1,286
Default

post up a log and tune on hptuners forum. Thin come back and link that thread to this one. I will look it over and try to help.
brandon6.0 is offline   Reply With Quote
Old 12-07-2017, 12:26 PM   #3
On The Tree
Thread Starter
 
MikeD.'s Avatar
 
Join Date: Mar 2012
Posts: 126
Default

MikeD. is offline   Reply With Quote
Old 12-07-2017, 07:41 PM   #4
TECH Senior Member
iTrader: (92)
 
01ssreda4's Avatar
 
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 23,139
Default

Simple, retune your MAF in OL. Corrections work the same only there is only one line to correct as opposed to an entire table like tuning the VE. Also, sounds silly but watch for small inconsistencies in important sensors like MAP. I had one that was responding sluggish and was giving me fits (similar to what you describe except it happened in OL as well) until i swapped it with a known good one.
01ssreda4 is offline   Reply With Quote
Old 12-08-2017, 05:44 PM   #5
On The Tree
Thread Starter
 
MikeD.'s Avatar
 
Join Date: Mar 2012
Posts: 126
Default

Looks like there actually may be some kind of Cat Test going on, and being i dont have rear o2s and there may some interference there. Still trying to figure out that I have everything set properly for that. Supposedy its common on p59 ecms
MikeD. is offline   Reply With Quote
Old 12-08-2017, 09:27 PM   #6
TECH Addict
iTrader: (1)
 
Join Date: Sep 2004
Location: Stockbridge GA
Posts: 2,607
Default

Make sure all of the proportional fueling tables are stock. Sometimes people mess around with those without knowing what they do, then they get overlooked, because there is no reason to mess with them. Also, I have never heard of unusual issues with a P59 other than the lean cruise and MAF fail quirks of the 2004 GTOs.
gametech is offline   Reply With Quote
Old 12-10-2017, 11:54 AM   #7
On The Tree
Thread Starter
 
MikeD.'s Avatar
 
Join Date: Mar 2012
Posts: 126
Default

Even if the injectors have changed, I should leave the proportional fuel tables stock?
MikeD. is offline   Reply With Quote
Old 12-10-2017, 06:58 PM   #8
TECH Addict
iTrader: (1)
 
Join Date: Sep 2004
Location: Stockbridge GA
Posts: 2,607
Default

Quote:
Originally Posted by MikeD. View Post
Even if the injectors have changed, I should leave the proportional fuel tables stock?
No, but I would put everything back to stock and begin making very small adjustments with regards to the proportional fueling. Who knows what the "tuner" may have changed. It is usually just easier to go back to a stock baseline and adjust than to try to find every little thing someone else may have screwed with.
gametech is offline   Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
PE Threshold Unpredictable & Inconsistent MikeSp PCM Diagnostics & Tuning 11 08-15-2017 11:15 AM
HPTuners SD VE Tuning with Wideband - Commanded AFR stuck at 14.7 for cruise? nskyline34 PCM Diagnostics & Tuning 13 03-25-2017 08:08 PM
5.3 LM7 diagnostic help aruss99 Generation III External Engine 0 02-13-2017 11:21 AM
Not sure what's wrong, problems since turbo install aaronware76 Forced Induction 26 02-08-2017 05:01 PM
B1 and B2 O2 sensors and fuel trims arent the same - O2s reading at different rates? nskyline34 Generation III External Engine 2 04-19-2016 07:48 PM


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 -5. The time now is 03:24 AM.


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: