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Thread: 2003 mustang gt fuel tuning help

  1. #1
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    2003 mustang gt fuel tuning help

    how in the world do you adjust fueling im still very new to this and i wanna increase fuel about 1500 rpms my afrs are running about 15 in that area cruising

  2. #2
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    Quote Originally Posted by [email protected] View Post
    how in the world do you adjust fueling im still very new to this and i wanna increase fuel about 1500 rpms my afrs are running about 15 in that area cruising
    By fueling, did you change your injectors or did you add a mod that allows more air in? Normally when you want to change fueling calculations and have kept your injector sizes the same you want to modify your MAF. In EECV it is mass airflow vs voltage in the airflow tab, where we use ADC instead of frequency. So setup a graph that plots your wide or narrowband over MAF ADC to get your AFR or O2 readings for the right range in VCM scanner. If you have changed physical injector sizes then you would have to put in your respective data in the fuel tab under general, but if you haven?t modified your fuel system, then you should leave this alone. Hope this helps.

  3. #3
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    thank you my tuner is about 100 miles away and it needs some adjustment i have a vortec v3 procharger upgraded fuel pump and 50lb injectors the tune is almost there but still have some hicups

  4. #4
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    Quote Originally Posted by [email protected] View Post
    thank you my tuner is about 100 miles away and it needs some adjustment i have a vortec v3 procharger upgraded fuel pump and 50lb injectors the tune is almost there but still have some hicups
    Yea your going to have to change some of the injector settings under the fuel tab and if your running higher than stock fuel pressure (~40 psi) your going to have to change that as well. If your going to drive it to your tuner I would be safe and take some timing out of it since it is FI.

  5. #5
    HPT Employee Eric@HPTuners's Avatar
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    At 1500 cruising ? Factory O2 sensors will be controlling the fuel trims and it should be around stoich (Lambda 1)
    Eric Brooks
    HP Tuners, LLC

  6. #6
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    I'm having an issue where I'm climbing a hill in 5th gear. The AFR is about 10 at about half throttle. When I get to the peak of the hill and start going down, reducing throttle, it leans out to about 16 to 20, almost like a fuel cut. The only way I found to stop this is to drop a gear or completely let out and hit the throttle again.

  7. #7
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    Quote Originally Posted by [email protected] View Post
    I'm having an issue where I'm climbing a hill in 5th gear. The AFR is about 10 at about half throttle. When I get to the peak of the hill and start going down, reducing throttle, it leans out to about 16 to 20, almost like a fuel cut. The only way I found to stop this is to drop a gear or completely let out and hit the throttle again.
    The car is supposed to lean out when you let off the throttle like that during coasting due to DFCO, I just have mine disabled while I?m tuning because it can throw off your data and in my case it causes really bad bucking when it leans out the mixture and advances the timing to 40+