Mass air voltage questions. no .5v reference.

BK_CAULEY

it's built for speed not longevity, woman
Dec 26, 2006
0
10
49
Thomasville, ga
Ok as the title states i have no reference voltage and to the best of my knowledge i should.

i have traced all wires up into the harness and none are damaged and seem to be in good shape. what could be causing this. The whole problem started when my car started running bad rich. I isolated it to the mass air. when i unplug it with the car idling nothing changes. and the car runs the same with it plugged up as it does when its unplugged.

I measured voltage from left to right starting at tyhe red wire.

First wire: 12v
second: ground
Third: nothing
Fourth: nothing

110608_201200-1.jpg
 

Attachments

  • 110608_201200-1.jpg
    110608_201200-1.jpg
    17.6 KB · Views: 427
  • Sponsors (?)


How to ck 4 wires.you did the 1st red already. to ck power ground hole 3.use volt meter . Key on connect +to pin 1red than grd to pin3 bk with lg should have 12v if not you start thier .you would use a multimeter to ck ohms on the other 2
 
no there is only four spots on it. and i grounded to the body when i checked for the 12v. i will test the ground tommorrow. and shouldnt one of the wires still have a .5v reference going to it. or does the mass air meter send the .5v out.

i am checking all this with the car off key on and with it idling.
 
Im just throwing ideas out there for you to think on. I have not dug into the maf system much.
 
I think it goes (not in the exact order tho but has) 12V to power the heating element...a ground...a 5 volt TO the meter and.... a signal return that the 5 volt goes through the element and depending on the air flowing through it changes how much voltage gets through and comes out the output....and should be at least around .5-.7 volts at idle at the output to the ecu.

unplug the meter and probe each wire with the key on and there should be a 12v and a 5v reference voltage.If theres no 5v going TO the meter it's not a bad meter it's a bad wire going to the meter.
 
All i can do is tell u fords pin test dc .other than bat volts all test are ohms .the pcm sends back 5v .it uses 4 wires but harness har 5 holes.i can do a write up of what it says but am i right with wire colors.any cel codes
 
I guess 66 pin test dc6 ck continuity of maf signal and vpwr circuits.key off set meter to 200 ohm scale. .unplug pcm unplug mass test pin 50 to maf sig record it than 37 with vpwr record it than57 with vpwr any thing more than 5 ohms indacates a short.if im right with colors i think DB/O is what you where asking 5v but thats when warm and running. That uses jumper wire to test not sure if you can probe wire?
 
didnt get a chance to pull the codes tonight. but i swapped my 19's back on with a stock meter and still the same.

i was letting my car idle tonight and unplugged the meter and the car ran exactly the same. what could be causing this? im now getting a 1-1.2 volt on the light blue wire at idle and my ground and positive are fine so now im stumped.
 
I did c to rule out a maf in say engine missing ,to rich or you get it .unplug maf and car runs smooth than bad maf .dont rush scan it and go from that .record all codes koeo koer and constant .in my 03 im hooked to predator im 1v to4v while driving