Quick Maf Question

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Sure what im say is can i use a maf set up for 42#injectors and a turbo on 30#injector N/A to test if my maf is bad. Because i think my maf is a stock maf with a pro-m logo and tube.
 
ok thats still bad. so one more shot. My car is a 89 its running super rich jerks at low rpm and surging idle from 400-1500 and stalls. when i unplugged the maf it smooths out but don't idle down quick. Anyhow the maf on it says its a pro-m 75mm 30c but i don't think its really calibrated for 30# injectors. so i want to Know if i put my brothers maf calibrated for 42# injectors and a turbo. would it work to see if smooths out on my 30#injectors and H/C/I car. When looking at the voltage at idle my pro-m maf reads the same as a stock one for 19# injectors and runs the same if i switch them out.
 
i think the one i have is cail for 19# or a stock one with a pro-m cap on top of it because as i said up a bit it runs the same when i put a stock maf on just dumping fuel and runs like crap
 
For the life of me I haven't the foggiest as to what the hell you are asking. Does it come in English please? I THINK you are trying to run a mismatched MAF that is not calibrated to your injectors and wondering why the car is not running properly?

Put the proper MAF back on and run the codes.
 
its hard to explain that why its hard to word. its really really f'd up thats what happens when you buy a blown up car in the dark. but what im trying to say is the maf that came with the car says its a pro-m 75mm 30c but the top part that says that was glued on with like white silicone not like it would from pro-m. so i put a stock maf on the car and it ran the same the voltage is the same. the car has 30# injectors and trick flow heads tf track heat intake f303 cam. NO code are thrown that would cause the problems im having. But when i unplugged the maf its runs fine

The problems im have are Running really rich, bad surging idle, jerking at low rpms.

What i wanted to know is if i put a 42# maf in it would it run lean instead of really rich. Because i don't think that the maf came with the car is really a pro-m one. i think its a stock 19# maf with a pro-m or a fake pro-m top cover on it.

i really hope i cleared things up here thank.

i just remembered that pro-m uses a white sticker to read the maf calibration this ones just all black .
 
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With the 42 it will tell the computer it is flowing less air than it really is, so yeah it will run lean... however, in cold start mode it will enrichen fuel. So disco the ect sensor would possibly richen it enough to idle. Might hard start though. Its on you if you nuke your engine though. You could dick with your fuel pressure to bump it up a lb or two. Disco the vac line to your fuel press reg would make the inj spray slightly more. I personally would try it to see what would happen because I'm curious and can afford to break :poo:. Its your car and property, ultimately.


I wouldn't let it heat up enough to start trying to read the 02 sensors though.
 
with the stock and the more then likey fake pro-m is 1.2volts at idle. and i checked all the wiring. my rebuilt motor has all black plugs with maybe 12 miles on it cleaned them let idle for maybe 1min and all black again thats how much fuel btw.
 
If there are stock electronics in a different housing, who knows what it is really doing. And the stock one with different injectors should not work. You need to match them up or it should run poorly if at all, just like it does.
 
No code 66 for the MAF?

Code 66 or 157 MAF below minimum test voltage.

Revised 10-Feb-2014 to add 95-95 Mustang code 157 and 94-95 ECC diagram

Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

Computer connector for 88-93 5.0 Mustangs
a9x-series-computer-connector-wire-side-view-gif.71316

Diagrams courtesy of Tmoss and Stang&2Birds

ECC Diagram for 88-90 5.0 Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


ECC Diagram for 91-93 5.0 Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif


94-95 Diagram for 94-95 5.0 Mustangs

94-95_5.0_EEC_Wiring_Diagram.gif


There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables. Changes in RPM causes the airflow to increase or decrease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

89-90 Model cars: Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

91-95 Model cars: Measure the MAF output at pins C & D on the MAF connector light blue/red and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.


At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.

Actually MAF pins C & D float with reference to ground. The signal output of the MAF is a differential amplifier setup. Pins C & D both carry the output signal, but one pin's output is inverted from the other. The difference in signal between C & D is what the computer's input circuit is looking for. The difference in the two outputs helps cancel out electrical noise generated by the ignition system and other components. Since the noise will be of the same polarity, wave shape and magnitude, the differential input of the computer electronically subtracts it from the signal. Then it passes the signal on to an Analog to Digital converter section inside the computer's CPU chip.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg