I can tell you this.When you do a speed density to maf conversion,you just simply disconnect the vacuum line from the map sensor and just plug the open vac line from the motor.LEAVE the wiring connected to the MAP sensor.When you unplug the vac line from the MAP (Manifold Absolute Pressure),it becomes a BAP ( Barometric Absolute Pressure..or Barometric Air Pressure ) sensor.On 89 - 93 foxes,those sensors are left in place for the Mass Air Flow sensor.Let me see if I can find an article on the swap.I know they are all over the place here.
That is what I thought, see I bought a slightly used ford kit since they dont sell them anymore, but for some reason my car only wants to run with the map and maf fully hooked up without the maf forget it, without map vac line will die randomly on idle??
I disconnected map again no surging idle, but it has a hard time catching the idle, like on startup, it wants to die down if you dont catch it, any ideas, I put a 75 throttle body and spacer, what is the corre3ct way to play with the idle? thanks.
I have done the conversion on my car and it runs great. Make sure you disconnect and plug the vacuum line off the MAP sensor and leave the wiring harness plugged in. Since you mentioned it was used, make sure the MAF sensor is clean. Get some carb or brake clean and spray it on the sensor itself and wait awhile to let it dry and try it again. Also you said you got a 75mm throttlebody, did you adjust the TPS when you put it on the new throttlebody? Make sure your TPS reads .997 volts in the idle position.
You did change out the PCM (computer) to a newer one that operates with MAF sensors correct? Oh and NEVER use carb or brake cleaner to clean out a MAF sensor.The chenicals within (acetone,toluene,benzene etc) can damage the plastics and leave residues.It can also corrode the delicate sensor wire.Instead use QD Electronic Cleaner or CRC MAF cleaner.
By carefully backprobing the harness plug on the TPS.Off the top of my head...I don't remember which 2 .perhaps HISSIN could chime in.I can have the info when I get home tho
spent some time searching found the way to test, thanks also I just realized the orange ground on the rear of my firewall is unhooked, anybody know where that is supposed to go and what it does?