Tuning For 24lb Injectors

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by 69idi, Feb 26, 2014.


  1. 69idi

    69idi New Member

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    ive upgraded to 24lb injectors, still have stock 55mm MAF. I am trying to tune the fuel slopes and stuff to make it right for the new injectors, I am wondering with the stock MAF do I need to change the voltage readings so I get a decent A/F ratio. I do not have data logging capabilities so I cant watch my ratios while driving.
    #1
  2. mikestang63

    mikestang63 Mustang Master

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    There are products sold that allow you to adjust the voltage signal on MAF's to adjust for different injectors. They work spotty at best IMO. Best bet is to either get a chip or a PRO M MAF setup for 24's.
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  3. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    what are you tunng with?
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  4. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    You generally do not need to tune for 24 lb injectors because they fall within the EEC's ability to compensate.

    It will take the EEC a little time with varied driving, to figure it all out though. Battery disconnects will start that process over.
    #4
  5. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    hold the press. Why do you even have 24 # injectors if you are still using a 55 mm maf???
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  6. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    Good question. lol
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  7. 69idi

    69idi New Member

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    well one of my friends recommended moates, and tuner pro rt? I bought the car from a guy who used it for drag racing, I drove it home with slicks on the rear. when I started driving it I knew that it had a lot of blow by, and had 24lb injectors in it. then I looked at the MAF and saw the part number and seen It was stock. so I knew it had to be running pretty rich. well I had some time off of work I decided to replace the clutch. I was convinced by my dad to re-ring and new bearing the bottom end. so I said Ill just rebuild the whole thing to go through it and know its right. after looking through everything, they built that engine for just out the gate power! im guessing the guy I bought it from had someone build the bottom end and do the heads. he put intake injectors and drive belt assembly together. im thinking the 24's were too rich and ruined the rings which gave me blow by
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  8. 69idi

    69idi New Member

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    see I have the A9l bin definitions and I think im going to change the injector high and low slopes. but if I change them will the MAF be telling the computer to open injectors like 4.5ms which the MAF thinks it has 19's and be running rich because it has 24's cause 4.5ms is 4.5ms but the 24's can inject more fuel at 4.5ms than 19's right?
    #8
  9. 88LX5.Oh

    88LX5.Oh Advanced Member

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    Does it currently have some sort of stand alone engine management system? If not, how do you plan on tuning it for the injectors?
    You may be making this harder than it has to be. You could simply throw a bigger (and calibrated MAF) on it and call it good. Later down the road you WILL want to upgrade the MAF (who the hell wants a 55 mm MAF) so just do it now and get it over with.
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  10. Grabbin' Asphalt

    Grabbin' Asphalt Mustang Master

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    Lotta trouble for 55mm on 19lbr's, .....:fuss:
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  11. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    What is the rest of the setup? Heads can intake gears etc?
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  12. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Definitely give us the rest of the combo. Sounds like overkill on a stock engine. Let the computer do what its designed to
    #12
  13. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    Were it me....

    A stock motor with stock induction/inlet tract doesn't require 24 lb injectors. The 19s that came originally in the car will support more power than the rest of engine combo will support so long as there's not forced induction to contend with.

    The problem with stuffing 24lb injectors into the combo with OEM meter and throttle body is low speed drive-ability. The minimum pulse for a 24 lb injector releases more fuel than a 19. Without the ability to aspirate more air, you'll consistently run rich.

    As mentioned before, this adjustment is usually within the EEC's ability to compensate (the differences between 19s and 24s isn't huge).

    Given this set of circumstances, here's what I would do:

    If I had a set of 19s laying around, I'd put them in and call it a day. Leave the 24s sitting in a zip lock bag and saturated with a light weight motor oil.

    --or--

    Spend a little cash and replace the mass air meter and throttle body.

    I'm sure that some of these guys can recommend a larger/compatible mass air meter from a different car (with part number).

    You might... MIGHT... even get lucky and find the entire top end from a junk yard (Meter, TB, upper and lower intake) from an explorer. While these mods do not provide HUGE gains, they do provide gains and will shift the bottle neck to the heads. More air = more fuel = a better match for your 24 lb injector and provide a better match for 24s while increasing power at the same time.


    Someone please chime in if I've missed something or you find a flaw in this plan.

    The other thing that comes to mind is that these mods will pave the way for a better flowing set of heads in the future that equate to even more power increases. It would be nice to have some of this ground work done and in great working order when you come across a great deal on a set of used (and larger) heads for your Windsor.
    #13
  14. f8tlfiveo

    f8tlfiveo My wife likes my spool and blow-off valve.

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    Put the 19's back in.. 24's are a waste of money IMHO. If you are not running any aftermarket heads 19's will work without forced induction.
    #14
  15. revhead347

    revhead347 I have face herpes.

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    The fastest and easiest way to fix the problem for now is to throw an aftermarket MAF calibrated for 24lb injectors. It's a good investment for the future anyway.

    Kurt
    #15
  16. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    Still waiting on what the combo is, car was raced? Did it have slicks and 24lb injectors with a stock h/c/i and t/b? I think the question at hand can be better answered with more information
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  17. mikestang63

    mikestang63 Mustang Master

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    I think the issue frankly is the OP believes larger injectors create hp, when the fact is they support more hp. You don't make HP by swapping in larger injectors unless the engine needs them.
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  18. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    And I was getting ready to trade my 235's in for 550's..... Back to the drawing board lol
    #18
  19. revhead347

    revhead347 I have face herpes.

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    I think the OP is honestly just trying to correct a mistake someone else made.

    Kurt
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  20. 69idi

    69idi New Member

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    hahaha I know 24's don't make horse power! the guy who built this setup I guess thought that way. the TB has been changed and I think the piece the MAF attaches to is bigger than 55mm. everyone says spend the money and get a calibrated MAF I've read they aren't accurate. this is my first mustang with EFI
    #20

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