Official Thread of Applicable Junkyard parts for Foxes

Don't take this the wrong way, but that's not a convincing argument. Just because the CEL isn't on or your car has no detectable issues doesn't mean everything is fine. Until you put the car on a dyno and map the A/F ratio and compare, you have no idea if you are running too lean or rich.

In other words it might work fine, but not ideal.

Car dyno'd 285 and 315 respectively with 10.5-11 AFR. You know, there is such a thing as over analyzing things. Again, it may not work for everyone BUT I had no issues with it. Just my first hand experience. The housing that the sensor sits in is exactly the same, even using the same mounting points. Its just much larger in diameter.

The A/F is very rich for a N/A car or one not running NO2. Rich best power is 12.5:1, lean best power is 13.5:1, best overall economy is 14.7:1. There is more power available by leaning the mixture out to the numbers I listed.

The Maf transfer is not the same for the 94-95 to the fox body style. It is very close but not the same.. The car will still run but not optimal. Mine actually ran pretty lean and didnt know it until I put the car on the dyno with some lambda readings. Now I have a wideband on the car and everything is tuned properly with the 94-95 Maf... But it is pegged at 5k, so I am gonna upgrade to a slot style and a bigger pipe. My car was running at 15afr and above at wot without the proper tune changes with the 70mm Maf.

Agreed. However, more power is available getting more air into the engine aswell. You are talking about tuning and I am talking about Junk Yard parts. Not everyone has the funds available to put the very best on their ride. Thats why this thread exist.

so is this finding the same as the MAF and sensors for the

1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,???

asking because there are alot of these at my pick n pull...

BTW i used the injectors of a grand marquis 4.6 (1992 i think) and they work great... there are 4 holes instead of the one holes found on stock foxes..

I think the 94-95 mustang gt sensors are the same as the ones you have listed. The f2VF I am pretty sure is what matters. That is the same as the 94-95 meter. The fox body housing and sensor are both different from the 94-95.

The injectors are 19 lb also.. They prob just have a better spray pattern with the 4 holes for better atomization.

There-in lies your problem. More than likely the computer is ignoring the MAF and is using preset tables instead. That's why your A/F is so far off.

If you look at the sensor it's self you'll see 2 wires. One of them sends a variable voltage to the computer. The wire is heated by current that passes through it much like an incandescent lightbulb. 2 things will affect this wire. Temperature (that's what the other wire measures) and the amount of air that moves over the wire. The wire is very sensitive and it's resistance changes easily depending on the amount of air and temperature of that air.

Now look at the housing. You'll see that there is a small sample tube that is cast into the housing that the sensor wires sit in. This is the only air that is measured. The air moving through the sample tube. It doesn't matter whether the housing size is 55mm, 70mm or 150mm. The sensor will only measure the air that moves through the sample tube.

The computer is programmed to know that the air that it measures through the sample tube must be multiplied by a certain factor, we'll use 10 as an example, because the total flow through that specific housing is 10 times greater than the air that moves through the tube.

Now if you take that same exact sensor and put it into a housing that flows 15 times as much air as the sample tube then the computer has no way of knowing that the total flow has changed. The computer looks at the O2 sensors and senses that the A/F has suddenly gone very lean. The computer keeps testing the two sensors to see if there may be something wrong with one of them. Since it can't reconcile a serious imbalance it simply stops looking at the sensors and resorts to it's preprogammed tables to operate the engine.

I don't know that the specifics of what I wrote are exact but that's the general idea of how this works.

what would be the difference in a 94-95 70mm MAF housing and say a 73mm C&L? neither have the electronics... just bigger housings

A bigger housing will flow more air. Without a way of telling the computer that something has changed, it will still think that you have the original 55MM housing. But since a given amount of air will slow down as the housing gets bigger the computer will think that there is less air going into the engine than there really is. The bigger the housing the slower the air will move over the sensor given a static amount of air being moved.

The way that calibrated sensors like the C&L work is simple. If the bigger the housing the slower the air moves is true (and it is) then the opposite must also be true. What the caibrated housing do is speed the air up that going through the sample tube. They do this by making the sample tube smaller than the original sample tube.

The reason they speed the air up is this.

Remember that the sensor is designed to go into a much smaller housing, 55MM in the stock Mustang's case. At specific RPMs the sensor sends a specific voltage to the computer. The computer is programmed so that when it receives a specific voltage from the sensor that will be X amount of air entering the engine.

So when you speed the air up that's going over the sensor the computer thinks that the engine is running at, for example, 2500 RPM instead of the actual 2,000 RPM. It will then add more fuel to accomodate the increased air flow.

As you make the housing larger and smaller you must trick the computer into giving the correct amount of fuel to match the air going in. Any changes in the housing must be accommodated by more tricking of the computer or making actual changes to the computer's programming.

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.

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 Kurtz Kustomz Motorsports, Inc. KKM 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.

You are looking at buying one or the other? But neither has the actual sensor, correct?

94-95 70mm housing - you buy a sensor for a 94-95 Mustang. Then the entire unit is a direct swap for a Fox (non-cobra) ecu w/ 19's.

73mm C&L - you buy a sensor to match the ecu that you have. 93 cobra ecu has a different sensor than manual/auto 5.0HO ecu's.

Thanks guys. I understand now, just need to make a decision.