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03 COBRA - Stalling and Hesitation after Tune - HELP?

Discussion in 'Tuning À la carte' started by DTW_COBRA, Jun 21, 2019.

  1. DTW_COBRA

    DTW_COBRA Member Established Member

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    Location:
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    So here's the background. I recently installed a ported eaton w/2.8 upper, ported accufab elbow, accufab SBTB, new 56lb injectors, used Kenne Bell BAP (w/o wire upgrade), NGK TR6 plugs (gapped at 0.030), JLT high boost CAI w/SCT 2600 MAF, AFCO heat exchanger. Everything else is factory except for Magnaflow catback.

    I've been working with VMP on the tune and have done a couple of requested datalogs. After 3 different tune files, finally got the car running good except for some random stalling out (when coming to a stop) and some random hesitation (feels like not getting fuel).

    Looking for any advice on what to check for these symptoms? Thanks in advance!
     
  2. decipha

    decipha Active Member Established Member

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    56lb injectors sound to be some type of off brand uncommon injector. More than likely your tuner doesnt have the info on them since most injector manufacturers dont publish data. If so they would have to dial the injectors in manually the hard way and with a modified inlet tract like you have that could be quite extensive. Would take no less than 60-80 tune revisions MINIMUM to properly dial in. It sounds like they did what most any tuner would do. They put in some generic data and raped the maf to get it in the neighborhood. Thats fine for cruise and wot but those transitional area where injector flow is non linear will cause issues such as your experiencing. The only way to properly dial the injectors in is to make a histogram that shows the total fuel error plotted across imaf counts and rpm. Only then can you start dialing in the injectors but be warned its a tedious process.
     
  3. DTW_COBRA

    DTW_COBRA Member Established Member

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    Location:
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    Thanks for the reply......but actually these injectors were recommended by VMP as the Siemens ones I originally had they said weren't compatible with their tune. They aren't generic/off brand, they're Ford OEM injectors. So I don't think the injectors are the issue in this case.
     
  4. slo984now

    slo984now AKA 01yellerCobra Established Member

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    Sounds like it just needs more tweaking. Tell the tuner what's going on.
     
  5. decipha

    decipha Active Member Established Member

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    I take it you have the 52lb injectors then

    2013-14 Shelby GT500 52lb fuel injectors

    thats odd they dont support siemens deka injectors that was basically the industry standard for many years

    if the injectors are legit then all that should be needed is some minor tune adjustments. Try to get a short log of it doing those quirks and shoot it off to them im sure they will be able to get you sittuated.
     
  6. DTW_COBRA

    DTW_COBRA Member Established Member

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    Location:
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    That's what I thought. He suggested them for driveability purposes, they have a 6-hole pattern vs. the Siemens 4-hole.
     
  7. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Premium Member Established Member

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    keep sending logs to the tuner until it's corrected
     
  8. TerminatoRS

    TerminatoRS New Member Established Member

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    I experienced a similar issue on occasion where the engine would puke when slowing down to make a turn. R's would come down when I threw the clutch in to downshift, stumble around 7-800, and die. Really nice to lose power steering mid-turn. Tuner said it could be something as simple as however the MAF is clocked in the intake tube. (I have the same intake as you, btw) The car was tuned right after that conversation with the tuner so I can't pinpoint the solution, but it potentially gives you a very simple starting point. My two cents anyway...
     
  9. decipha

    decipha Active Member Established Member

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    If tuned properly it should be near impossible to stall

    it sounds like it needs more dashpot down low
     

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