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Thread: Tuning 2001 Cobra Questions

  1. #1
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    Tuning 2001 Cobra Questions

    So starting the journey of tuning my car.

    The car is a 2001 Cobra.

    It is a 5.1L stroker 4V with 11-1 compression fresh build.
    Heads have slight bowl work and freshly redone, Upgraded Valve Springs and Comp CCA-106260 cams degreed to CAM card.
    Intake manifold is stock 2001. JLT intake Lightning MAF
    Exhaust consists of BBK Longtubes and off-road h-pipe.
    Fuel System is new 39lb injectors and factory everything else ( i do have an upgrade fuel pump to add in but have not installed yet as I am contemplating forced induction and know I will need a revamped setup)

    I am working with an unknown Procharger tune on a 2001 Cobra PCM (my PCM got bricked by a dealer, while trying to reflash PCM and PATS).

    So far I have updated Fuel Injector Data and a Base MAF profile

    Fuel System:

    Utilized data from Ford Racing 39Lb injectors.
    InjectorData.PNG

    I took all data and added to what I think is appropriate area and re normalized data to match on tables.

    For example I took
    ALOSL (lb/s) -("low" injector slope) of 0.011404 = Flow Rate Low ([ECM] 12010 - Injector Flow Rate Low: Injector Flow Rate for low commanded fuel mass values.)

    Additionally I took FNPW_LSCOMP (Multiplier to low slope as function of injection pressure in psid) and re-normalized it to HPT Flow Rate Low Multi vs Pressure FNPW_LSCOMP.PNGHPTFLOWMULTI.PNG

    Is this the correct way?


    Additionally, since this is a Procharger tune I am assuming some of the fuel pump voltages will be off but I do not have access to factory information at this time. Though I did check it doesn't appear it is setup for a return setup as the voltages are not maxed.

    How critical are fuel pump voltages and tuning for this? Any links to tuning this appropriately?

    For MAF

    I used decipha's MAF Transfer Curves to pull the data on the 90mm Lightnight MAF
    http://www.efidynotuning.com/maf.htm
    I figured this could be a good starting point to adjust from.
    MAFTransfer.PNG
    Re-normalized to match data converted Voltage to ADC by multiple voltage by 204.6
    HPTMAFVolt.PNG

    Any issues with this method?


    Also on the Engine>General>Displacement I have updated this to .00167lb since I am utilizing a stroker motor.
    Idle was increased to 850rpm since it has aftermarket cams.


    Car will startup and idle though startup requires some throttle to get it to run once it is running it idles and runs decent.

    My plan is to dial in MAF, by forcing open loop Engine>Fuel>Oxygen Sensors>CL 02 Sensor Temp - 2500?F.

    I will datalog the following: MAF ADC, EQ Cmd, WB02 EQ.

    And adjust MAF by ADC and the variance between WB02 EQ & EQ Cmd.

    Any other tips or thoughts? I will post current file and current stabilized datalog in next post as I work on it.

    Additionally, this car is seeing gauge drops while data-logging so I will be troubleshooting that as well. to see if anything specific is driving the issue.

  2. #2
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    Tune File and Start-up Idle Log

    See attached for the tune file as well as log file.

    I am seeing the fuel source go to CL stoich eventhough I have high CL O2 temp, is it truly going into CL or is it still in OL for MAF tuning?

    See EQ ratio differences between banks does that mean O2 sensors are giving feed back. I thought OL ingore 02s?
    Attached Files Attached Files

  3. #3
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    that scalar will not prevent closed loop

    in order to stay in closed loop the open loop threshold function needs to be set to 0 load

    you should never force open loop to dial in the tune. Let the o2s do it for you and simply apply their correction. No need in doing any extra work when the ecu does it for you.

    if lambses are jumping around its because its in closed loop.

    yes the maf is a good start

    you corrupted the tune by changing the x axis top cell value from 128 psi to 60psi.

    On EEC-V the interpolation lookup routines do not have any limits so if it goes outside of the function it will grab garbled data and corrupt the ecu forcing a reset or worse corrupt values that can cause unexpected behavior. Like wot fuel going to stoich and commanding 57 degrees of timing.

    NEVER CHANGE THE TOP OR BOTTOM X AXIS VALUE ON ANY FUNCTION IN EEC-V.

    Also note worthy. Being a high compression 4v boosted engine you dont need much timing certainly nothing like the 03/04 cobras. The C headed 4v engines do not tolerate ignition timing at all with high compression and boost.

    For example, a typical modded 03-04 cobra usually makes max power on 93 octane at 20 degrees of timing up top. Some people shoot more to them even 23-24 degrees but they always loose power.

    The same engine with nothing more than a piston change to up the compression to 11:1 will make the same power at 10 degrees of timing and usually wont tolerate much more without detonating.

  4. #4
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    Quote Originally Posted by decipha View Post
    that scalar will not prevent closed loop

    in order to stay in closed loop the open loop threshold function needs to be set to 0 load

    you should never force open loop to dial in the tune. Let the o2s do it for you and simply apply their correction. No need in doing any extra work when the ecu does it for you.

    if lambses are jumping around its because its in closed loop.

    yes the maf is a good start

    you corrupted the tune by changing the x axis top cell value from 128 psi to 60psi.

    On EEC-V the interpolation lookup routines do not have any limits so if it goes outside of the function it will grab garbled data and corrupt the ecu forcing a reset or worse corrupt values that can cause unexpected behavior. Like wot fuel going to stoich and commanding 57 degrees of timing.

    NEVER CHANGE THE TOP OR BOTTOM X AXIS VALUE ON ANY FUNCTION IN EEC-V.

    Also note worthy. Being a high compression 4v boosted engine you dont need much timing certainly nothing like the 03/04 cobras. The C headed 4v engines do not tolerate ignition timing at all with high compression and boost.

    For example, a typical modded 03-04 cobra usually makes max power on 93 octane at 20 degrees of timing up top. Some people shoot more to them even 23-24 degrees but they always loose power.

    The same engine with nothing more than a piston change to up the compression to 11:1 will make the same power at 10 degrees of timing and usually wont tolerate much more without detonating.
    Ah ok. So look at average LAMBSES in range compare with average WBO2(LAMBDAs) and adjust from there, looking to get my STFTs down to +-1 Correct? Do i need to disable LTFT learning or anything like that?

    Regarding injector data just assume 60psi multiplier for 128 and assume 20 psi multiplier for 0 on these or should I extrapolate these numbers?

    Is it better to just interpolate/extrapolate multipliers vs changing x axis values?

    I believe when this motor was tuned initially it had around 12 degrees of timing, Prior to head work and degreed cams, they where installed straight up before.

    The plan was to get idle/part throttle dailed in then work on WOT and timing. Not sure if that is the right process or not.

    I greatly appreciate your time on this decipha i known you have a plethora of knowledge regarding tuning the EEC-V platform and taking your time to help those of us trying to use HPTUNERs says a lot about you as a person.

  5. #5
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    Quote Originally Posted by JayRab View Post

    Additionally, this car is seeing gauge drops while data-logging so I will be troubleshooting that as well. to see if anything specific is driving the issue.
    You're not alone with the gauge issue. I'm having that issue with my 99 Cobra also.

    It seems that I don't have the drop-outs when only logging one parameter. Multiple parameters (seemingly any, haven't found a particular trigger parameter) cause a gauge drop out, and lack of data collection.

    I'm using the latest beta VCMScanner. Haven't tried the stable release yet.

  6. #6
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    Quote Originally Posted by CamS View Post
    You're not alone with the gauge issue. I'm having that issue with my 99 Cobra also.

    It seems that I don't have the drop-outs when only logging one parameter. Multiple parameters (seemingly any, haven't found a particular trigger parameter) cause a gauge drop out, and lack of data collection.

    I'm using the latest beta VCMScanner. Haven't tried the stable release yet.
    Yes, they are suggesting wiring issues with the car. I verified I did not miss any grounds yesterday and It didn't change the datalogging.

    I was unable to log anything without drop-outs including 1 parameter.

    It was suggested to pull fuses 1 by 1 to try and see what specific circuit could be causing the issue to help determine the issue. I plan on trying that one day this week after work. Ill probably start another thread just for this issue.

  7. #7
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    the cluster gets its signal from the ecy over the same scp network (obd-2 port). When the gauge cluster drops out its because the device on the obd2 port is not communicating how the ecu is expecting it to.

    you can disable adaptives while dialing in the maf if it makes it easier for you

    thats fine no need to extrapolate the 0psi and 128psi deltap so long as its accurate in the deltap range youll be using. Most people just use stock of 40psi deltap.

    yea interp/extrap-ing the y axis for the stock x axis value is fine

  8. #8
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    Finally got some time i try and tune on the car. Recently installed new o2 sensors as 1 was not reading correctly.

    I am seeing large variance bank to bank on stfts at idle as well as surging idle set at 850 rpm seeing swings from 780-900.
    idlevariance.PNG

    the variance lessens with rpm from what I can tell.
    freerev2000.PNG

    From research this tells me it is possibly an exhaust leak before O2s but there are none i could find. Could injector issues cause this or would the bank to bank variance not change with rpm.

    what about cam timing? if cam timing was off would the variance stay as rpm increased?

    here is log with warm idle and rpm sweep as well as current tune

    rev7idlewithswipe.hpl
    2001Cobra000000007.hpt

    any help or thoughts appreciated

  9. #9
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    cam timing as well as the injectors not dialed in can cause bank to bank variances

    dial in the maf first and then you can see how it traends and start dialing in the injectors

    what is your warm idle isc duty cycle? if its greater than 30% or so you need to open the throttle stop to have it idle correctly. Ive seen bone stock engines surge horribly because the throttle stop was too far closed.

  10. #10
    I had a similar issue with my 04. Bank one was adding a ton of fuel and bank two was pulling. My wideband was installed on bank one. As the revs went up they came pretty close. At idle wideband on bank one would read 14.7 - 15.0. Narrow band on bank one would read dead lean and every once in a while it would pick up. It idled like crap too. Long story short, one of the brand new motorcraft plugs was bad. Installed a new one and trims were pretty even. My theory was I had a intermittent misfire and the wideband was too slow to pick it up but the narrow band caught it. The culprit plug was cylinder four. When I plugged all of the plugs that one looked to be fouled with soot. The rest looked perfect. I pulled the new one out a couple of thousand miles later and it looks perfect. It was weird and hate to admit it kicked my butt. 😭

  11. #11
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    Quote Originally Posted by decipha View Post
    what is your warm idle isc duty cycle? if its greater than 30% or so you need to open the throttle stop to have it idle correctly. Ive seen bone stock engines surge horribly because the throttle stop was too far closed.
    I should mention I have an aftermarket throttle body as well as I know that typically can cause some idle tuning issues as well.

    Do not see a way to log isc duty cycle. I can log idle control(STIT) in lbs/min, if I understand correctly this is the amount of air added or removed to keep the car at commanded rpm.

    So if idle control STIT is greater than 30% change over base MAF airflow I should change the throttle stop?

  12. #12
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    Quote Originally Posted by momotunes View Post
    I had a similar issue with my 04. Bank one was adding a ton of fuel and bank two was pulling. My wideband was installed on bank one. As the revs went up they came pretty close. At idle wideband on bank one would read 14.7 - 15.0. Narrow band on bank one would read dead lean and every once in a while it would pick up. It idled like crap too. Long story short, one of the brand new motorcraft plugs was bad. Installed a new one and trims were pretty even. My theory was I had a intermittent misfire and the wideband was too slow to pick it up but the narrow band caught it. The culprit plug was cylinder four. When I plugged all of the plugs that one looked to be fouled with soot. The rest looked perfect. I pulled the new one out a couple of thousand miles later and it looks perfect. It was weird and hate to admit it kicked my butt. 😭
    Good Idea i will check plugs when I change the oil this weekend and see what they look like.

  13. #13
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    In all my years I've never seen nor heard of anyone ever having issues with mechanical throttle bodies. It either lets air through or it doesnt theres really nothing to them.

    what you want to do is get her up to a warm stable idle and adjust the throttle stop so the iscdc is below 30%. Ideally 10% is perfect. If its an aftermarket isc valve then some of them dont work below 40%.

    Then just dial in idle air and dashpot.