Mass Air Meter Modification

The mass air flow sensor (MAF sensor)

Is mounted on the cover of the air cleaner. Uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool. It then sends out an analog voltage signal to the Powertrain Control Module (PCM) to determine the intake air mass. The PCM will then calculate the required fuel injector pulse width in order to provide the desired air/fuel ratio. Note: The 1992-1995 SC MAF meter voltage curve was the same  as the 1993 (#24lb) Mustang Cobra had.
MAF Sensor Data
Two aftermarket companies that offer replacement MAF sensors. Vortech uses a 73mm or 76mm diameter body and depending on your injector size has replaceable sampling tubes. Example: 1/2" diameter hole for #19 or stock injector applications or 3/4" diameter hole for #36lb injectors that were installed on a SC originally equipped with #30lb injectors. Your original MAF sensor is reused in the Vortech body.


 

Pro-M uses a 75mm diameter body for use with your stock air cleaner box and comes with new electronics. Each Pro-M is calibrated for a specific injector size by changing the sampling tube size and MAF signal back to the PCM.


To modify the stock 70mm MAF body equipped on 1992-1997 Thunderbirds for increased flow follow the steps below.

Step One: Disconnect the MAF wiring harness and remove the stock air box from the (black) air intake tube.

Next, loosen the clamp and remove the 3 screws that hold the MAF in place.


 

Once the MAF is off the air box remove the MAF sensor using a anti-tamper torx bit to remove the two screws that hold the sensor in place. Be careful not to damage the wires while removing the sensor. Lay the sensor in a safe place and do not touch the small wires. Also remove the two anti-tamper torx screws that hold the backing plate to the center support inside the MAF.
 

Step Two: Place the MAF in a vice being careful not to damage the aluminum housing. Using a hack saw cut the center support out. Make one cut just below the sampling tube and the other about one inch from the bottom.

 

After removing the center support grind the excess metal away using a die grinder and metal bit.

Be careful not to damage the sampling tube while grinding the metal away. Once you have finished removing the metal clean up with water and or brake cleaner. Next, you will need a drill and a NEW 15/32" drill bit. Preferable is a drill press for more accurate drilling and use some oil to help the drill cut through the aluminum.
 


If you have to use a hand held drill (not recommended) let the drill bit guide your drill into the sampling tube and don't try to force the bit down.

 

Step Three: After the MAF body has been cleaned up using brake cleaner check for any burs in the sampling tube and file them away.

Next, using a file round the sampling tube opening smooth so the air has a better transition. A chain saw sharping file works best. After all work is done to the MAF body clean with brake cleaner and reinstall the MAF sensor in the body. Make sure you insert the black rubber O-ring back into the MAF body before installing the sensor. Do NOT reinstall the sampling tube backing plate!  Hand tighten the torx bits down to about 5ft-lb (don't over tighten).

Reinstall the MAF back into the air box, then install the air box back into the car and reconnect the MAF wiring harness. Check all clamps to the intake tube and start the car.

For the best flowing intake kit on a SC check out the 80mm Intake Kit. This kit is a direct bolt-on to any 89-95 Thunderbird SC.

MN12 Performance Inc. 
703-968-6513 
richt@mn12performance.com