89-93 Ford Fox Body Mustang 5.0: A9L / GUFB family


The Fox Body Mustang switched to using a Mass Air Flow meter to measure airflow in 1989.  Uses TFI distributor, sequential injection for up to 8 injectors, MAF air metering.  This EEC-IV system became the blueprint for future Ford systems (EECV and beyond) for years to come.  Initially hindered by a lack of datalogging capabilities, this platform has been able to truly shine with the help of Moates tuning tools.  These ECMs are known to have the hardware ID “SFI-MA12A” and it is unknown which other hardware IDs can run the GUFx strategies.

Hardware for Tuning

  • QuarterHorse – integrated device brings unique functionality to the table.  It is a “chip on steroids” that allows you to make changes while the vehicle is running and (with supporting software) log live data from the vehicle.
  • F3 – simple chip module that can store one or two tunes and switch between them while vehicle is running.  Requires Jaybird programmer or BURN2+FA.
  • F3v2 – simple chip module that can store 8 tunes and switch between them while vehicle is running using the switch module sold separately.
  • F8 – fancy chip module that can store eight tunes and switch between them while vehicle is running.   Can also be programmed while installed – no need to remove chip to reprogram it.  Requires Destiny programmer
  • BURN2 + FA + FE – generic chip programmer with Ford adapter (FA) and ECM interface (FE) that can be used to read the current program from EECIV and EECV ECMs on the bench.

Software for Tuning

Although several different strategies (or “operating systems”) were used on this generation of computer, all of them are capable of using the GUFB (i.e. A9L) code.  All stock ECMs with the same processor code on the label have the same code inside the ECM which is typically downloaded with tuning software.  It is not critical to read your own ECM.  This is a very common, well supported application.  Any of the three tuning softwares that we sell will work for this application.  Any tunes developed using a QuarterHorse can be programmed to F3/F3v2/F8 chips for long term use

  • Binary Editor ($100 – $171 available from Moates.net) is a Ford-specific graphically oriented tuning software that supports many EEC-IV and EEC-V processors.  There are several options for BE:
    • Free built-in definitions for BE come with the software.  They’re reasonably complete and work really well.  Support GUFB (A9L, etc.) GUF1 (A9P, etc.) and GUFA (others) natively
    • Core Tuning definition ($extra available through Coretuning.Net) – uses same standards for organization as other Core Tuning defs, very complete.
    • EEC Analyzer ($50 available from Moates.net) is an optional companion program to Binary Editor to assist with analyzing data and automating tuning tasks.
  • TunerPro RT (fully functional free trial with nag screen / $39 to register available from Moates.net) is a universal tuning software that supports the GUFB strategy editing using definitions available on TunerPro’s website.
    • Definitions available elsewhere on support site only support GUFB (A9L) natively.  Auto cars can be tuned using GUFB by setting appropriate options in a GUFB bin file.
    • Alternative GUFX definitions available from decipha / EFI Dyno Tuning  support several extra features and code patches and are designed to work with the “A9L2” bin file
  • EEC Editor ($30 / $35 available from Moates.net) is a Ford-specific tuning software that supports both the GUFB, GUF1 and GUFA strategies
    • Reasonably complete editing definitions
    • Reasonably complete logging definitions
    • Does not run well on all computers.

Recommended Combos

Just want to know what to buy?  All of these will be valid combos that will allow you to tune a vehicle effectively.

(Ford Dealer Kit)

(QuarterHorse AND Jaybird AND F3 AND Binary Editor WITH Dongle AND Wideband)

(QuarterHorse AND Jaybird AND F3 AND TunerPro RT AND Wideband)

(Jaybird AND F3v2 AND TunerPro RT)