Changing To Mass Air

Discussion in 'Fox 5.0 Mustang Tech' started by claysstang, Dec 26, 2013.


changing to mass air from speed desnity

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  1. i have a mustang 88 that has speed desnity in it that im thinking of changing to mass air???
    i have a A9L computer with complete wiring harness no mass air yet will this work and how hard will it be to replace the wiring harness???
    also will a 4.6 mass air meter work on the 5.0????
  2. All you need is the mass air harness itself, the part that plugs into the maf sensor and has 4 wires coming from it. It's not too difficult. Your car is a manual right? That computer won't work in an auto

    Scroll down a bit. The $40 obd1 harness is what you want.

    Grab a mass air computer that matches your trans, and pick up a stock meter and intake tubes.

    Get the system running, then worry about upgrading the mAF metersmeters
  4. whats the reason for swapping to Mass Air? Unless you are throwing on a blower or a huge cam, there really is no benefit. That being said, you got good advice and I'll just add you need to convert the MAP to a BAP sensor by removing the vacuum line and capping off the intake bung.
  5. Swapping the MAF sensors between different MAFs is a big no no. The MAF body and sensor are designed to match each other. Therefore you can't swap sensors between different part number MAF bodies and maintain proper calibration. The assembly is designed to match the computer’s internal program, and swapping a different MAF can upset the computer's calibration. In other words, your monster MAF probably won't match the calibration of your 5.0 Mustang computer.

    The OEM Ford MAFs are not calibrated to injector size. The injector sizing is done in the computer’s internal programming. Aftermarket MAF’s “lie” to the computer in an attempt to fool the computer into changing the injector pulse on timing to match the increased airflow.

    The only other MAF that is a one for one swap for a 93 and earlier 5.0 Mustang is the 94-95 Mustang MAF.

    94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes. *1 *2

    Once your replacement 70MM MAF is in place, disconnect the battery for about 10 minutes. When you reconnect the battery and start the engine, the computer will relearn the settings for the new MAF.

    *1.) Metal flange adapter Buy the TR70 for $44.95. Or spend some time on eBay looking for one that may fit.

    *2.) MAF & sensor interchange
    The 94-95 Mustang 5.0 MAF & sensor is also found on:
    1995-94 Mustang 3.8L F2VF-12B579-A2A,
    1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
    1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
    1994-92 Town Car 4.6L F2VF-12B579-A2A,
    1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
    Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.

    MASS air conversion instructions from FREE

    A9L (5 Speed) computer from junkyard $100-$150
    A3M (5 Speed) computer from junkyard $100-$150
    A9P (Auto or in a pinch, it will work in a 5 Speed car) computer from junkyard $100-$150
    70MM MAF from 94-95 Mustang GT - $40-$70
    MASS Air wiring harness kit $30-$85

    The whole thing is probably less than $300 using junkyard parts.

    A9L computers are 5 speed only
    A9P computers are automatic, but will work with a 5 speed.

    The conversion harness seems to work well for most folks. It avoids the compatibility problems in using a harness from the junkyard. Simple and cheap, actually less work that swapping the wiring harness.
    Conversion Harness kits & parts
    Also see for help with the harness parts, and connector pins,

    If the idea of moving & soldering wires scares you, here's a list of compatible Mass Air wiring harnesses.

    Copied from bbunt302
    Just for reference, here's a list of all the compatible years:

    89 harness should work for 86-89 as long as you're using mass air.
    90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
    91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)

    Late 92 through 93 harnesses may be compatible (single dash connector, fuel pump relay under the hood). You may end up running some extra wire for the fuel pump relay. Comments and input from someone who has actually used the 92-93 EFI harness would be nice.
  6. I agree, unless running a blower or a Cam, mass air conversion isn't worth the time and effort
  7. Incorrect.

    1989-1993 Mustang 5.0: Rated at 210-225 HP: 19lb factory fuel injectors
    1989-1995 Taurus SHO: Rated at 220 HP: 24lb factory fuel injectors
    1989-1991 Thunderbird S/C: Rated at 210 HP: 30lb factory fuel injectors

    Each and every one of these applications came from the factory with the EXACT SAME mass airflow housing, calibrated with the same transfer function and the exact same part number on the electronic sensor module.
  8. JR stated you can't mix and match different part numbered sensors and housings. And your posts just states that there's 3 different cars using the same MAF meter and housing. Am I missing the point here?
    jrichker likes this.
  9. @Blown88GT

    My comments were primarily directed at those who would swap parts without giving much thought to the possible mismatch. Too many guys would put that 80 MM MAF on a pushrod 5.0 Mustang and never give a thought as to if it was compatible with the computer's internal program.

    Quoted from my original post:
    "Swapping the MAF sensors between different MAFs is a big no no. The MAF body and sensor are designed to match each other. Therefore you can't swap sensors between different part number MAF bodies and maintain proper calibration."

    Quote from C&L website:
    "Each and every one of these applications came from the factory with the EXACT SAME mass airflow housing, calibrated with the same transfer function and the exact same part number on the electronic sensor module."

    To me that sounds like the same idea is being presented.
    C&L is not making a statement that you can use a XYZ sensor on a housing designed to use a 123 sensor. What they are saying is that the same grouped sensor and housing assembly can be used on multiple engine combinations due to changes in the computer's internal program. Computers are amazingly complaint: as long as you don't divide by zero or try to make the program counter register decrement, they will do what you tell them to do.

    Are we talking about the same thing or is it Zebras and Giraffes?
    The input that I got from the tweecer guys (VRIStang & friends) was that the 94-95 Mustang MAF and the other MAFs listed as having the same housing and sensor assembly are compatible. They are the only MAFs with a transfer curve close enough to the stock 5.0 MAF to not require a custom tune.
    #9 jrichker, Dec 27, 2013
    Last edited: Dec 28, 2013
  10. 94-95 Mustangs are SN95, same 5.0 engine as the Fox body.

    I have been unable to veryify if there are any differences regarding the MAF: ACT located in MAF housing which changes the sensor connector to 6 pins instead of 4 pins, i.e. 2 extra pins needed for the ACT. Other models started earlier than 1994, i.e. 1993 Explorer. The Megasquirt guys have the same confusion as the Tweecer guys. See the section on Deleting the MAF:

    Even this reference doesn't have it 100% correct:
    I have seen 6-pin oval connectors that were not on 2005 & up vehicles. IIRC, the were on Explorers from the 90's.

    Only way to know for sure is roam the junkyard & take notes & pics.

    Ford only made the SN95 configuration for 2 years, 18-19 years ago. Not many originals running around with 5.0 V8's with no mods.

    The easiest way to refer to this matter, is if it has 4-pins, the sensor assembly is the same for all, Mustang or other Ford model; if it has 6-pins, the actual hot wire is the same, but the sensor housing is different. To confuse things even more, some MAF housings are 3"OD on one end &* 3.5"OD on the other end. Others have a flange on the outlet end.

    I know for sure that the thermactor system is different; I have Ford Motorsport ceramic coated headers that I got from a guy with a '95 who was changing to long tubes. There is a port on the passenger side header which we only had to plug off. It's a perfect fit.

    I no longer have to deal with EEC's & MAF. I now have a Megasquirt which uses an onboard MAP sensor. Starts & idles better than any other combo of EEC's & MAF's.

    Know anyone that wants a newly refurbished A9L? I now have 2 & will only keep 1.
    Also have a couple MAF's with sensors, one housing is stock, the other we milled off on the CNC.
    #10 Blown88GT, Dec 28, 2013
    Last edited: Dec 28, 2013
  11. The 94-95 Mustang MAF has a 4 pin oval wiring connector. The wiring is the same as the 89-93 5.0 Mustang MAF. I have one running in my 89 5.0 Mustang at this time.

    The 94-95 Mustang MAF uses a 4 bolt flange which requires an adapter to mate with the slip on ducting for the 89-93 5.0 Mustangs.. I got mine off the Pro-M website many years ago before they got into some kind of business problem and left the arena. They have resurfaced again as
    #11 jrichker, Dec 28, 2013
    Last edited: Dec 28, 2013
  12. I was pretty sure they were 4-pin, too.
    If you mill off the flange, the adapter is not needed. It's the same diameter as the non-flanged.
    I have 2 spare housings with sensors, someone will want 1 someday.