Junkyard Mass Air ???'s

Justin111

Member
Nov 28, 2011
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Hello,

I picked up two mass air meters from the junkyard the other day. One from a
95 thunderbird 4.6 liter part number F4SF-12B579-AA and another from a 1995 mustang 3.8 liter part number F2VF-12B579-A2A. Both I believe are 70mm.

I got both of them because because the mustang one has a flange at the end opposed to the slip duct end on the thunderbird one.

My question is do I swap electronics from the mustang 3.8 liter one to the thunderbird one?

My car is a 89 5.0 with stock 55mm mass air.

I know a 3.8 mass air meter will work with a 5.0 but I don't know if a 95 thunderbird 4.6 meter works.
 
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My guess is that it probably will work OK. There is a simple test to find out: get a friend to ride with you who has a stop watch. My El Cheapo Casio watch from Wal Mart has a stop watch function, so the stopwatch part of the test shouldn't be too difficult.

Then do a 2nd or 3rd gear run from 1500 RPM to 5000 RPM without shifting gears. Do it with the stock meter and then with the Tbird 4.6 meter and compare the times. Just remember to disconnect the battery for 5 minutes when you swap the MAF.

I have used the 95 Mustang MAF in my previous 89 5.0 GT, and it worked very good. I got a flange from the local speed shop that was a perfect fit.
 
Sure, it might run and idle just fine, but will it perform under load the way it does at idle? I'd hate to have a mismatched MAF meter creating havoc with the ECU because it wasn't metering the proper airflow?

Anyone have any legitimate proof of a Junkyard Mass Air success story, or are we just assuming it works because the housing itself is capable of supporting a larger volume of air?
 
The meter body is calibrated to a specific injector size, the sensor on the meter is not.

1. Got a complete MAF from a 1995 Explorer V6-3.8L (that's what was written on the wrecked vehicle), F07F-12B579-A2C. The body is a 55mm with flange.
2. The MAF from my Ford Motorsport Conversion Kit is E9ZF-12B579-AA

It appears that the operative number is: 12B579

Decoding Ford part numbers
Classic Mustang Part Number Decoding Guide
Decade of Manufacture:
E = 1980, 1st digit
F = 1990, 1st digit
0 thru 9 = Decade Year, 2nd digit
Z= Mustang, 3rd digit
F= Engine Accessories or Electrical and Electronics Division, 4th digit

I believe the Decade Year is the first year of manufacture for the part, not the year it was made.
For items referenced above:
E9ZF = 1989 Mustang Engine Accessory
F07F = 1990 Explorer Engine Accessory
 
The meter body is calibrated to a specific injector size, the sensor on the meter is not.

1. Got a complete MAF from a 1995 Explorer V6-3.8L (that's what was written on the wrecked vehicle), F07F-12B579-A2C. The body is a 55mm with flange.
2. The MAF from my Ford Motorsport Conversion Kit is E9ZF-12B579-AA

It appears that the operative number is: 12B579

Decoding Ford part numbers
Classic Mustang Part Number Decoding Guide
Decade of Manufacture:
E = 1980, 1st digit
F = 1990, 1st digit
0 thru 9 = Decade Year, 2nd digit
Z= Mustang, 3rd digit
F= Engine Accessories or Electrical and Electronics Division, 4th digit

I believe the Decade Year is the first year of manufacture for the part, not the year it was made.
For items referenced above:
E9ZF = 1989 Mustang Engine Accessory
F07F = 1990 Explorer Engine Accessory

Not completely true. The meters are not calibrated to a injector. They are calibrated to give a certain voltage per given mass of air. I don't know what meters had a transfer function the same as a fox body mustang but I do know for sure that a 94-95 mustang GT or cobra mass air will work. There may be others that are the same but I am not sure.
 
MAF Sensor
While many of these meters will work, some will need you to run your own electronics (so you're only using the tube), and MOST will requrie some sort of aftermarket tune to work correctly. From what I've read the only one that is a direct bolt in replacement is the 94/95 5.0 or 3.8 that works with 19lb injectors (part# F2VF-12B579-A1A or A2A)., although I've read yes and no for the 4.6 Thunderbird's 70mm unit when you remove it's electronics and re-use your own
4.6 mass air meters (2v=70mm 4v=80mm)
Lincoln Mark 8, 80mm for 24lb
90mm Lightning MAF for 42# injectors
92-95 SuperCoupe, 70mm for 36's
Ford Mustang 1994-1995 V6 or 5.0L 70mm
Ford Crown Victoria 1992-1994 4.6L 70mm
Lincoln Towncar 1992-1994 4.6L 70mm
Mercury Grand Marquis 1992-1994 4.6L 70mm
94-97 Thunderbird 4.6 70mm housing is a direct bolt on to stock fox maf bracket. (I suspect same housing as 93 cobra.) This appears to be part # F4SF.

I went by this thinking if the thunderbird housing is 70mm and uses a slip duct on both sides. I can just put the 3.8 liter mustang sensor in the housing without messing with a flange.

I'm on a budget so thats why I'm going the cheap route. I got them both at the junkyard for 25 bucks.

Thanks,

Justin
 
The 94-95 gt Maf will work but the Maf transfers are a little bit different..i put one on my car and it ran a little to lean at wot for my taste compared to the stock unit.. It was around 15.5, and had a couple spots where it was closer to 17 afr at wot when I had it on the dyno. Now I have a quarterhorse tuning device. So I adjusted the Maf transfer appropriately to get the afr around 12.5 afr at wot
 
The meter body is calibrated to a specific injector size, the sensor on the meter is not.

1. Got a complete MAF from a 1995 Explorer V6-3.8L (that's what was written on the wrecked vehicle), F07F-12B579-A2C. The body is a 55mm with flange.
2. The MAF from my Ford Motorsport Conversion Kit is E9ZF-12B579-AA

It appears that the operative number is: 12B579

Decoding Ford part numbers
Classic Mustang Part Number Decoding Guide
Decade of Manufacture:
E = 1980, 1st digit
F = 1990, 1st digit
0 thru 9 = Decade Year, 2nd digit
Z= Mustang, 3rd digit
F= Engine Accessories or Electrical and Electronics Division, 4th digit

I believe the Decade Year is the first year of manufacture for the part, not the year it was made.
For items referenced above:
E9ZF = 1989 Mustang Engine Accessory
F07F = 1990 Explorer Engine Accessory
The first 4 digits are the Engineering number, not a part number.
They signify the original use of the MAF meter. Some Engineering number MAF's were reused for other vehicles several years later. For example the 'F2VF' MAF was engineered in '92, but was used on the 94-95 Mustangs.
As near as I can tell, the 'calibration' for the MAF sensor is specified in the second 2 digits... VF in the 94-95 Mustang. ZF for the fox Mustang.
SF for the 93 Mustang Cobra.

I have no idea what the 12B*** number signifies, but I've never seen a need to pay attention to it.
I've found a lot of meters in the local pick and pull, just by looking at the first 4 digits and the housing size...
Some meters will also be marked with something like '70afh' below the part numbers for the sensor. The '70' signifies a 70mm housing.


F07F-12B579-A2C
E9ZF-12B579-AA
These 2 meters are completely different!
'7F' vs 'ZF'

Another example of how useless the 12B579 number is can be seen in the first post of this thread...
Hello,

I picked up two mass air meters from the junkyard the other day. One from a
95 thunderbird 4.6 liter part number F4SF-12B579-AA and another from a 1995 mustang 3.8 liter part number F2VF-12B579-A2A. Both I believe are 70mm.
The F4SF and F2VF are completely different calibrations, but they have the same 12B579 numbers.
 
Sure, it might run and idle just fine, but will it perform under load the way it does at idle? I'd hate to have a mismatched MAF meter creating havoc with the ECU because it wasn't metering the proper airflow?

Anyone have any legitimate proof of a Junkyard Mass Air success story, or are we just assuming it works because the housing itself is capable of supporting a larger volume of air?
I'm running the exact same meter setup as the OP on my car.
Swapped an F2VF sensor into a housing similar to what the 93 Cobra had.

My little n/a 2.3 liter won't test the top end of the MAF, so I can't vouch first hand on that.

But my MAF transfer is dead on in the regions I use...
I've used the fox transfer and the 94-95 transfer... same result...
 
The first 4 digits are the Engineering number, not a part number.
They signify the original use of the MAF meter. Some Engineering number MAF's were reused for other vehicles several years later. For example the 'F2VF' MAF was engineered in '92, but was used on the 94-95 Mustangs.
As near as I can tell, the 'calibration' for the MAF sensor is specified in the second 2 digits... VF in the 94-95 Mustang. ZF for the fox Mustang.
SF for the 93 Mustang Cobra.

I have no idea what the 12B*** number signifies, but I've never seen a need to pay attention to it.
I've found a lot of meters in the local pick and pull, just by looking at the first 4 digits and the housing size...
Some meters will also be marked with something like '70afh' below the part numbers for the sensor. The '70' signifies a 70mm housing.


F07F-12B579-A2C
E9ZF-12B579-AA
These 2 meters are completely different!
'7F' vs 'ZF'

Another example of how useless the 12B579 number is can be seen in the first post of this thread...

The F4SF and F2VF are completely different calibrations, but they have the same 12B579 numbers.
Are you saying this is incorrect?
Classic Mustang Part Number Decoding Guide
I'm not referring to the MAF body or calibration, only the sensor.
The part number for the sensor only is: 12B579
According to Probst, the EEC-IV MAF sensors are all the same. It's nothing more than 2 precision resistors, one is Ambient, the other is Hot Wire.
You don't need to pay attention to it because they are all the same for the 4-pin connector.

C&L makes bodies with replaceable calibration tubes.

IST has brand new sensors for '86-'93:
Part Number MS-7655-F, Sensor Only.......................................$99.95
 
No, in fact I basically stated what was on that site, didn't I?

I'm not referring to the MAF body or calibration, only the sensor.
The part number for the sensor only is: 12B579
So then what the hell good is the 12B579 number?
Can't you tell it's a MAF sensor by looking at the part?
Do you need that 12B579 number for anything?

According to Probst, the EEC-IV MAF sensors are all the same. It's nothing more than 2 precision resistors, one is Ambient, the other is Hot Wire.
Exactly the point.
If all you look at is the 12B579 number, then you will be calling all MAF sensors interchangeable. That simply is not the case.

You don't need to pay attention to it because they are all the same for the 4-pin connector.
Exactly.
But if you thought this way, then why would you say...

1. Got a complete MAF from a 1995 Explorer V6-3.8L (that's what was written on the wrecked vehicle), F07F-12B579-A2C. The body is a 55mm with flange.
2. The MAF from my Ford Motorsport Conversion Kit is E9ZF-12B579-AA

It appears that the operative number is: 12B579
What this implies is that the 2 part numbers you listed are equivalent. This is wrong.
(F07F-12B579-A2C) not equal to (E9ZF-12B579-AA)
The 12B579 number is irrelevant

Also...
The meter body is calibrated to a specific injector size, the sensor on the meter is not.
1. injector size has no place in the discussion of factory Ford MAF calibrations.
2. As a matter of fact, the sensor IS where the calibration is done. The MAF housing is simply a housing. You are confusing what C&L does, with what Ford does.




C&L makes bodies with replaceable calibration tubes.

IST has brand new sensors for '86-'93:
Part Number MS-7655-F, Sensor Only.......................................$99.95
C&L has NOTHING to do with a discussion on stock Ford MAF meters and their interchangability.
Throwing aftermarket sensor manufacturers part numbers into the discussion will only cloud the issue.
I won't enter those discussions at this point.
 
As near as I can tell, the 'calibration' for the MAF sensor is specified in the second 2 digits... VF in the 94-95 Mustang. ZF for the fox Mustang.
SF for the 93 Mustang Cobra.
I should clarify this statement, as I think it is why Blown wants to argue...

I correlated the above calibrations to specific Mustang models/years, not because that is what the calibration was engineered for, but because those are the vehicles we most often discuss.
I have no idea what the SF calibration was originally engineered for, but it's safe to assume it wasn't the Cobra...