Help! 5.0 Not Running Right

Discussion in 'Fox 5.0 Mustang Tech' started by austin86gt, Jan 2, 2014.


  1. austin86gt

    austin86gt New Member

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    I have a 1986 mustang gt with a 302 bored .030 over with trick flow twisted wedge heads and trick flow upper and lower manifold and plenum. i have a bbk 65mm throttle body with bbk cold air kit. i have the cobra X3Z computer and 24lb injectors in it. my maf number is E92F-12B579-AA and this thing just does not want to run right. my fuel pressure is at a constant 39lbs and my tps readings are proper. timing is set perfectly and all. it idles very oddly and when it comes to WOT it falls flat on its face and sputters. soon after my headers will just start to glow read. it seems to me to be getting too much fuel but when i put my injectors back in they looked very old and the tips were cracked? would that be a possibility of whats wrong or maybe that i need a 70mm maf rather than the 55mm thats on it? I would appreciate any help on this very much!
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  2. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    Your EEC, injectors and MAF are not correct.


    That's a standard 55MM mAF, which cannot be used with the cobra EEC.

    You can find a 93 Cobra MAF, or ditch the cobra EEC (not considered to be a great EEC) and swap to an A9L and get a mAF calibrated for 24# injectors. Or do a custom chip.

    Your choice which route...but that's more than likely your issue
    #2
  3. 90lxwhite

    90lxwhite Mustang Master

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    Dang this guy is pretty sharp
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  4. austin86gt

    austin86gt New Member

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    Awesome man thanks so much! now if i went and got a A9L what maf size would be best? 70mm? and would the E92F-12B579-AA sensor work for this setup without a tune?
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  5. austin86gt

    austin86gt New Member

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    Awesome man thanks so much! now if i went and got a A9L what maf size would be best? 70mm? and would the E92F-12B579-AA sensor work for this setup without a tune?
    #5
  6. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    that maf is made for 19# injectors so will not work with the a9l without being tuned
    Last edited: Jan 3, 2014
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  7. mikestang63

    mikestang63 Mustang Master

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    Ford factory MAF meters are not calibrated to the injectors like aftermarket ones. They are matched to the EEC. The A9L, A9P are setup for 19lb injectors and a corresponding MAF. The Cobra EEC is setup for 24lb injectors and the matching MAF. Aftermarket MAF's trick the computer by adjusting the voltage in the signal wire so the computer thinks there is still the stock MAF and injectors.

    As stated, you either need to find a Cobra MAF which matches the Cobra EEC, or get the A9l and a Pro M 70 or 77 MAF calibrated to 24's . Your stock MAF meter would require a tune to get it to work with the Cobra EEC.
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  8. austin86gt

    austin86gt New Member

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  9. austin86gt

    austin86gt New Member

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    Thanks man! so my car has no egr. is that gona mess up my computer and give me problems?
    #9
  10. Grabbin' Asphalt

    Grabbin' Asphalt Mustang Master

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    Pull your codes and go from there concerning the EGR and related code solutions. However you can block it off but it would create your computer to act funny 99% of the time or you can correctly get a chip tune to properly cut it off so it will not throw codes or cause operation mishaps, sputtering, idle etc.
    #10
  11. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    EGR is hit or miss. Right one, tackle one thing at a time. You need a MAF calibrated for 24# injectors, or take the A9L and go get a custom tune.
    #11

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