Results 1 to 20 of 20
Like Tree2Likes
  • 2 Post By SMWS6TA

Air Fuel Ratio Question

This is a discussion on Air Fuel Ratio Question within the General Help forums, part of the LSx Technical Help Section category; I know in cool air your A/F ratio is going to change up some. My car has a SD tune ...

  1. #1
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Air Fuel Ratio Question

    I know in cool air your A/F ratio is going to change up some. My car has a SD tune so there's no MAF to make the adjustments it would normally do if I was a stock engine.

    From my understanding the higher the number the leaner the mixture is, it this correct?


    Duringthe summer months I average 14.6'ish on my wideband gauge. Last couple of weeks and it's been cold, I noticed it's been in the mid 15's to low 16's. Even after it's warmed up. Today it was high 60's and will be back in the mid 70's later on. It is still showing mid 15's.


    Should I be worried?


    Also how the hell do I know what plugs I'm suppose to be using? By that I mean the temp range of the plug? Currently using NGK TR6 plugs.
    Last edited by SMWS6TA; 01-12-2017 at 08:55 AM.

  2. #2
    Senior Member Whamhammer's Avatar
    Join Date
    Sep 2010
    Location
    Bel Air, Maryland
    Posts
    1,324

    Silver
    '02 Trans Am WS-6, 6M

    Quote Originally Posted by SMWS6TA View Post
    I know in cool air your A/F ratio is going to change up some. My car has a SD tune so there's no MAF to make the adjustments it would normally do if I was a stock engine.

    From my understanding the higher the number the leaner the mixture is, it this correct?


    Duringthe summer months I average 14.6'ish on my wideband gauge. Last couple of weeks and it's been cold, I noticed it's been in the mid 15's to low 16's. Even after it's warmed up. Today it was high 60's and will be back in the mid 70's later on. It is still showing mid 15's.


    Should I be worried?


    Also how the hell do I know what plugs I'm suppose to be using? By that I mean the temp range of the plug? Currently using NGK TR6 plugs.
    Higher numbers are leaner. Are those numbers that you are getting at idle?

    I wonder if you have a small vacuum leak, or if you just need a tweaking of your tune?

    I don't remember if oxygenated gases force a leaner running condition but most states don't run it in the summer but do in the winter.

  3. #3
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    At idle and while driving.

    All summer it was in the 14's to low 15's.

  4. #4
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    My A/F ratio doesn't really fluctuate much, Scott, regardless of the weather. It is almost always pegged right at 14.7 at idle.

    And to just have another confirmation, yes, the higher the ratio, the leaner the mixture. This is why when you floor it, your A/F goes way down....you want it to be richer under load.
    It's on jackstands.

  5. #5
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    It sounds like those are idle A/F numbers that you posted, correct? If so, as the engine is not under any load the leaner A/F mixture isn't an issue -- I see my wideband reading bounce into the 15's at idle on our car from time to time. The question is whether you are lean under load as that is when there can be a problem. The best indicators of this are timing being pulled due to knock detection, audible knock, or plugs that read lean.

  6. #6
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Ah.....I see now.


    Well under load it's currently in the low 15's, let off the pedal and it spikes up but get back in it drops back down.


    Cruising at 80mph it stay mostly at I would say 15.2ish every once in a while 14.8 or as high as 16.0.

    It was 70 here today with the normal 95% humidity.

    Plugs were changed about a month ago. No knocking or back fires either.

  7. #7
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    Do you have a scanner to see if it is pulling timing when you get on the go pedal?

  8. #8
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    That seems lean under load to me. I know I'm FI, but at WOT my A/F is around 10.7.

    Sent from my SM-G900V using Tapatalk

  9. #9
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Quote Originally Posted by pajeff02 View Post
    Do you have a scanner to see if it is pulling timing when you get on the go pedal?
    No but working on getting one.

    Quote Originally Posted by 35th-ANV-SS View Post
    That seems lean under load to me. I know I'm FI, but at WOT my A/F is around 10.7.

    Sent from my SM-G900V using Tapatalk

    Under load it's dropping into the high 14's/low 15's.

  10. #10
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    Yeah, that's a bit lean. WOT our A/F generally drops to the 11.5 - 11.8 range. Is your A/F gauge one that can be calibrated?

  11. #11
    Senior Member Whamhammer's Avatar
    Join Date
    Sep 2010
    Location
    Bel Air, Maryland
    Posts
    1,324

    Silver
    '02 Trans Am WS-6, 6M

    Quote Originally Posted by 35th-ANV-SS View Post
    That seems lean under load to me. I know I'm FI, but at WOT my A/F is around 10.7.

    Sent from my SM-G900V using Tapatalk
    A/F ratios are lower for FI than NA, the range depends on the amount of boost

  12. #12
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    Quote Originally Posted by Whamhammer View Post
    A/F ratios are lower for FI than NA, the range depends on the amount of boost
    I assumed as much. His load values are high still though.

    Sent from my SM-G900V using Tapatalk

  13. #13
    Senior Member Whamhammer's Avatar
    Join Date
    Sep 2010
    Location
    Bel Air, Maryland
    Posts
    1,324

    Silver
    '02 Trans Am WS-6, 6M

    Quote Originally Posted by 35th-ANV-SS View Post
    I assumed as much. His load values are high still though.

    Sent from my SM-G900V using Tapatalk
    Agreed, the question is that why, and how much it needs to be brought down.
    SLP Air Lid/Smooth Bellows
    Kooks Emissions LT Headers/Catted Y pipe
    NGK TR55 plugs
    Magnaflow Cat-back
    Spohn Front Upper Tubular Control Arms
    UMI Front Lower Tubular Control Arms
    UMI Rear Lower Control Arms/ Adjustable Panhard Rod
    Factory C5 Z06 17x9.5 wheels w/ 285-40-17 Continental Extreme Contact DW's all the way around.
    Dyno Dynamics dynoed @:
    356 rwhp, 360 rwlb/tq

  14. #14
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    Yeah. I don't really know much about the tuning aspect of these cars, or any car for that matter lol. I would recommend not getting on it though until he figures it out. Lean under load is not good and can quickly destroy a motor.

    Sent from my SM-G900V using Tapatalk

  15. #15
    Member DaddySS's Avatar
    Join Date
    Oct 2005
    Location
    Bergen Co. NJ
    Posts
    590

    Black
    2000 Camaro SS Conv.

    colder air is more dense and therefor the same volume of air will have greater mass when cold. As long as you're wondering what plugs to use - pull one from each bank and read the plugs. There are lots of good references on the web for plug color and temperature. That will tell you if it's running lean and or hot/cold.
    2000 SS Conv, M6, Onyx - SLP Lid, CAI, TTS LTs, AFR 205s, 220 224 581 581 114, Z6 Int. & clutch, 3.73s, GMMG, ASP, 160 stat, Rapid tune, STB, LCAs, Brkts, SFCs, SLP 1LE, Hurst Billet+.TTIIs (Gunmetal), BFG KDWs. 406rwhp, 376rwtq + 2011 Camaro Vert Triple Black

  16. #16
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Air Fuel Ratio Question

    Last Tuesday I sent the gauge off to Glowshift for testing. It quit working. I know why too. I have a leaky seal because when I pulled the gauge out it was soaked. So now working on how to seal the seam between the gauge pod and the a pillar so it doesn't do this again.
    http://www.ls1.com/forums/f7/my-6-liter-build-174257/

    http://www.ls1.com/forums/f8/my-8-8-rear-build-165553/

    6.0L Block - Forged 403 built, breaking it in , Polluter Stg3 Cam, FAST 102mm Intake, NW102 TB, MSD wires, NGK TR6 plugs, Truck Coil Packs, LS3 Fuel Injectors, CC Pacesetter LT Headers, TS&P ORY, QTP e-Cutout, Magnaflow Muffler, 104mm Air Lid & Line Lock, Catch Can, Stage 2 T56 w/Viper shaft, PRO 5.0 Shifter, Tick MC, Monster Stg 4 Clutch, QT SFI BH, MWC DSL, UMI: SFC, PHB, LCA's, LCA Relocation Brackets & TA, Hotchkis Springs (1" Drop), YR1 Snowflake Wheels wrapped in NT555 tires & Custom Fab Ford 8.8 rear w/4.10 Yukon Gears, WSQ Hood, 3"CM Strange Eng Drive Shaft.

    Horsepower never lies, but is often lied about!

  17. #17
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    Yikes! That's not good. T-top seal or windshield the source of the leak?

  18. #18
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Air Fuel Ratio Question

    nope it's a door issue, meaning the spot that the motor sits on on the door has elongated. I'm working on a fix...

  19. #19
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    Ok - fortunately the doors are a part of our car that I have not had to play with, yet.

  20. #20
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    Got my replacement wideband in and good news my numbers are in the 14's and under WOT they go down into the 12's. So the old gauge must have had a short before it died and that was why my numbers were off.

    I also made a drain hole and added some single sided tape to fill in the gap along the seam so if any more water gets past the seal it shouldn't fill up the gauge pocket.


    I did tinker with the window and I can't seem to get it to raise the front any higher then it's going to go. I may have to take it to a window shop and have them do something if it still causes issues.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Air/Fuel Ratio Gauge question
    By johngoodman in forum General Help
    Replies: 3
    Last Post: 08-14-2011, 04:22 PM
  2. Air Fuel Ratio at WOT
    By rchops33 in forum Computer & Tuning
    Replies: 22
    Last Post: 07-08-2009, 02:00 PM
  3. Fuel/Racing Fuel Ratio
    By Whiteboycntdnce in forum General Help
    Replies: 3
    Last Post: 11-22-2007, 06:27 AM
  4. Optimum air/fuel ratio?
    By SS#1531 in forum General Help
    Replies: 12
    Last Post: 10-03-2006, 10:25 AM
  5. Air / Fuel Ratio Gauges....HELP
    By SSNAKEATER23 in forum Computer & Tuning
    Replies: 3
    Last Post: 02-22-2006, 06:22 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •