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Thread: Lean Condition on acceleration (have been using transient fuel) low o2 millivolts

  1. #1
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    Lean Condition on acceleration (have been using transient fuel) low o2 millivolts

    Hello all,

    I have a pretty much one-off set up with my car and have been battling a lean condition on acceleration for a while now. First of all I will tell you about the car:

    2001 Pontiac Firebird/Firehawk 38K miles
    LS3 short block bored and stroked to a 429ci all forged internals etc.
    Trick flow cathedral port heads (can't remember intake runner size off the top of my head)
    Fast 102 intake and Nick Williams throttle body
    Custom 4 inch intake tube with larger snouted intake box (don't know brand, had it on car when I bought it)
    Custom ground Comp cam 238/243 duration at .050" lift, 112 LSA, .617" max lift..can't remember advertised duration
    4l80e B&M Transmission with manual valve body
    Moser 9" with pro comp center section
    Fully adjustable suspension with tubular k member etc
    N/A no boost or nitrous

    Anyways, the car is currently running on speed density with the custom operating system installed. I have been vigorously calibrating the VE table, so it should be dialed in with LTFT's in the right neighborhood. So with that said, I started adjusting the transient fuel settings and adding to the fuel to wall impact factor, as well as the gain and the boiling time. This has gotten me in the right direction, but I am still seeing lean popping at acceleration and hearing popping randomly when crusing, but no lean condition indicated on my wideband in car. I started looking at my datalog more and saw that the o2 millivolts were getting really low, like in the 50s and 60s when this lean/popping condition is taking place. Then when the car comes out of it, the o2 sensors oscillate as normal. I understand the o2 sensors only measure oxygen in the exhaust, but I'm wondering if the sensors are actually ceasing to work (which usually would show 450 mlv from what I understand) and this is causing the lean condition, or if the o2 sensors are reading really low because of the lean condition. Now sometimes my STFTs kick up to 12% in these situations which would lead me to believe the o2 sensors are working properly, but when I actually look at the histogram the STFTs in those corresponding cells are not that high. So I'm chasing my tail here and definitely in need of any help I can get. Anyone have any advise? I'm including my calibration and config/scan files as well.

    Thanks in advance!transient 8.hptSpiking lean from takeoff 01 Firehawk.hpl

  2. #2
    Quote Originally Posted by apeit001 View Post
    Hello all,

    I have a pretty much one-off set up with my car and have been battling a lean condition on acceleration for a while now. First of all I will tell you about the car:

    2001 Pontiac Firebird/Firehawk 38K miles
    LS3 short block bored and stroked to a 429ci all forged internals etc.
    Trick flow cathedral port heads (can't remember intake runner size off the top of my head)
    Fast 102 intake and Nick Williams throttle body
    Custom 4 inch intake tube with larger snouted intake box (don't know brand, had it on car when I bought it)
    Custom ground Comp cam 238/243 duration at .050" lift, 112 LSA, .617" max lift..can't remember advertised duration
    4l80e B&M Transmission with manual valve body
    Moser 9" with pro comp center section
    Fully adjustable suspension with tubular k member etc
    N/A no boost or nitrous

    Anyways, the car is currently running on speed density with the custom operating system installed. I have been vigorously calibrating the VE table, so it should be dialed in with LTFT's in the right neighborhood. So with that said, I started adjusting the transient fuel settings and adding to the fuel to wall impact factor, as well as the gain and the boiling time. This has gotten me in the right direction, but I am still seeing lean popping at acceleration and hearing popping randomly when crusing, but no lean condition indicated on my wideband in car. I started looking at my datalog more and saw that the o2 millivolts were getting really low, like in the 50s and 60s when this lean/popping condition is taking place. Then when the car comes out of it, the o2 sensors oscillate as normal. I understand the o2 sensors only measure oxygen in the exhaust, but I'm wondering if the sensors are actually ceasing to work (which usually would show 450 mlv from what I understand) and this is causing the lean condition, or if the o2 sensors are reading really low because of the lean condition. Now sometimes my STFTs kick up to 12% in these situations which would lead me to believe the o2 sensors are working properly, but when I actually look at the histogram the STFTs in those corresponding cells are not that high. So I'm chasing my tail here and definitely in need of any help I can get. Anyone have any advise? I'm including my calibration and config/scan files as well.

    Thanks in advance!transient 8.hptSpiking lean from takeoff 01 Firehawk.hpl
    what injectors are you running?
    Owner of Cunningham Motorsports

    06 z06
    2016 camaro
    68 Camaro
    2014 e63 amg
    07 LBZ Duramax

  3. #3
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    They are 65lb injectors. Can't remember brand off the top of my head. I will get a part number on them stat.

    Thanks

  4. #4
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    Got the data

    My apologies, the injectors are 107961 Siemens Deka injectors. Anyone have the proper data for these?

    Thanks

  5. #5
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    Okay,

    So I replaced my injectors with FRPP 62# injectors and used the Bannish data. I also have now changed plugs, wires, fuel filter, and O2 sensors...still no luck. Car is actually running worse. Any ideas? Anyone please.

    Thank you

  6. #6
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    mate those siemens injectors are good man....you need the psi amount at what lb/hr they run...ie say [email protected] psi and what your rail pressure is ie 58psi and then use the injector data spreadsheet plug in the info and get the info from it.......excel/ injectors......cheers Bret Ultimate Lsx Tuning.......Forgot to ask apeit001 what do you mean you can hear POPPING mate....Sometimes not enough timing can cause that POPPING sound..... mate by rights with that set up I would tune with a wideband....Had a quick look your VE map and dude those cells down low between 400rpm- say 2800rpm ARE DANGEROUSLY LOW/LEAN BROTHER....I would get your R.A.F dialed in first and get your idle fueling close to stoich say 14.5-14.7 or lambda 1.0 depends on fuel type....once you get those both done then concentrate on other areas
    Last edited by THE CHAD; 04-18-2014 at 03:11 AM.

  7. #7
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    apeit001 mate, i'll have a look at your tune now and see what I can help you with mate....

  8. #8
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    R.A.F looks like way too much air at running temp mate...Have you used Russ Kemp airflow.cfg......Great way to dial in your R.A.F....I run the same intake manifold/nw 102mm and mine aint no where near as much......idle adaptive airflow max in gear/acoff and max p/n acoff not the same?...Get hold of a WIDEBAND mate and tune that VE map....Short pulse limit (injectors) needs changing mate too low.....those injector settings don't look right dude.....ie offsets/min injector pulse/defaults /flow rate etc......if you had the siemens 60lb installed these are the flow rates as follows =69.259597 69.693632 70.127667 70.561703 70.995738 71.429773 71.801803 72.235838 72.669873 73.041903 73.475938 73.909973 74.282003 74.716038 75.088068 75.522103 75.894133....

  9. #9
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    also hehe under power Enrich mate change the Enrich ramp in to 1.0000.....PE delay 0 rpm? don't know if your OPsystem is different but 3500rpm?....Any KNOCK mate 30-31* W.O.T.......timing map could do with a bit of SMOOTHING dude too many dips and troughs.......your overspeed/underspeed tables need to be changed ie mate put the stock settings back in them both and then reduce the tables by 50% which will help it to stabilize idle and driveability ....

  10. #10
    Advanced Tuner JamesLinder's Avatar
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    Sample Tune for 2000 SS Camaro with 408 Stroker and Fast 102 Intake

    You cannot tune with LTFT's; it simply does not work. Install a wide band in one of the 2nd bungs for OEM sensors and tune by zeroing out the error
    between commanded lambda and measured lambda according to wide band logged in the HP Tuners scanner. I tried what you are doing and believe
    me it does not work. Not even close. I have a similar setup, and maybe my tune will be helpful to you, however no 2 motors are going to behave
    the same even if they are identical components.

    I have:
    Custom Built, Forged 408 CID LQ9 - TX Speed & Performance
    (thank you Gary Luther)

    WiseCo 4.030 -8cc Pistons, Lunati Rods, 24x Lunati Crank
    199-AsCast, Precision Race Components cathedral cylinder heads 68cc; 10.7:1
    TSP Custom Order Comp Cams: 227/235 .614/.621 on 112LSA
    GM LS7 hydraulic lifters; 1.7 ratio GM shaft rocker arms with trunion upgrade
    PTM 102mm Throttle Body; Fast Toys 104mm Air Cleaner Lid with ram air hood
    FAST 102mm Cathedral-Port Intake Manifold (146302)
    TSP 100mm MAF, 2006+ Corvette Z06 GM MAF Sensor (recalibrated IAT)
    Bosch 41.7 lb/hr at 4 bar fuel injectors #0280155811
    Kooks Long-Tube headers with Y-pipe; CATs removed
    GZ Motorsports LSX Series Sportsman Crankcase Vacuum Pump Kit
    Meziere 680-WP319S Electric Water Pump
    Racetronix Fuel Pump Kit (255L/Hr integral Walbro pump)
    2000 Camaro OEM PCM (GM service code 09354896)
    Manual-Shift 4L65E Level 5 Transmission & 2400 billet converter (PATC)
    Attached Files Attached Files

  11. #11
    Advanced Tuner JamesLinder's Avatar
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    My advice would be not to change transient fuel and do not change injector timing; none of that is required to tune your build.
    Just because HP Tuners lets you change all these parameters doe not mean you should. If you find yourself having to change
    these parameters then you have other problems that are more fundamental in nature.

  12. #12
    Advanced Tuner JamesLinder's Avatar
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    ALSO, always tune your MAF and allow both MAF and VEs to control fueling! I agree that going back to closed loop is probably not a good
    idea because the narrow bands are not needed once you tune the motor properly IF the MAF is left in operation, mostly because the narrow
    band sensors are not located in the right place any longer once you install headers. I have found once you have the tune dialed in properly,
    the throttle response is better if you leave the PCM in open loop.

  13. #13
    Advanced Tuner JamesLinder's Avatar
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    if you screw up the injector data, you are certain of failure before you even begin tuning. Injector data must be absolutely correct before doing anything else.

  14. #14
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    Quote Originally Posted by JamesLinder View Post
    You cannot tune with LTFT's; it simply does not work. Install a wide band in one of the 2nd bungs for OEM sensors and tune by zeroing out the error
    between commanded lambda and measured lambda according to wide band logged in the HP Tuners scanner. I tried what you are doing and believe
    me it does not work. Not even close. I have a similar setup, and maybe my tune will be helpful to you, however no 2 motors are going to behave
    the same even if they are identical components.

    I have:
    Custom Built, Forged 408 CID LQ9 - TX Speed & Performance
    (thank you Gary Luther)
    Yeah you are right JamesLinder but one question mate....Why have you tuned and still have a MAF in place....
    WiseCo 4.030 -8cc Pistons, Lunati Rods, 24x Lunati Crank
    199-AsCast, Precision Race Components cathedral cylinder heads 68cc; 10.7:1
    TSP Custom Order Comp Cams: 227/235 .614/.621 on 112LSA
    GM LS7 hydraulic lifters; 1.7 ratio GM shaft rocker arms with trunion upgrade
    PTM 102mm Throttle Body; Fast Toys 104mm Air Cleaner Lid with ram air hood
    FAST 102mm Cathedral-Port Intake Manifold (146302)
    TSP 100mm MAF, 2006+ Corvette Z06 GM MAF Sensor (recalibrated IAT)
    Bosch 41.7 lb/hr at 4 bar fuel injectors #0280155811
    Kooks Long-Tube headers with Y-pipe; CATs removed
    GZ Motorsports LSX Series Sportsman Crankcase Vacuum Pump Kit
    Meziere 680-WP319S Electric Water Pump
    Racetronix Fuel Pump Kit (255L/Hr integral Walbro pump)
    2000 Camaro OEM PCM (GM service code 09354896)
    Manual-Shift 4L65E Level 5 Transmission & 2400 billet converter (PATC)

  15. #15
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    Yeah JamesLinder i agree and as i said tune with a wideband.....Mate one question i noticed you have a MAF in place why is that , with me that is the first thing i throw away especially with a Cathedral Port headed combo......Not so much of a problem with the Later model Square port type ie L76/98/LS3......Idont like and wont rely on the MAF especially with cams/heads/strokers ....hehe...i know that comment might upset a few guys but that's my opinion and only that's all, A lot of guys in AUS don't run them with big mods....I run any moded lsx with a O.T.R for a direct ram style effect for power/torque/throttle response/driveability/ and cooler int temps........About injector data boys your first thing you should/need to do is when you purchase new injectors before you commit to buy them get the data associated with them it will save you a lot of headaches...My advice is if the supplier can not provide the CORRECT DATA for them well what are they doing with them in the first place and if they don't know anything about them well why are they selling them....I would move on and not buy them without the correct data.....cheers Bret Ultimate Lsx Tuning...........PS Apeit001 if you need any help with your combo i can help you mate, just purchase a Wideband dude.......James Linder nice looking car mate
    Last edited by THE CHAD; 04-19-2014 at 04:11 AM.