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Old 02-25-2014, 10:30 PM   #1
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Default 1.8 MAF wiring diagram help

Hi, I am trying to use a spare 1.8 MAF sensor I have in my garage for my Mechanical Engineering controls project. I can not find a wiring diagram to find the pin out for the sensor. Does anyone know the pins?

Were using it to create a PID feedback controller for a dynometer fan for my School's FSAE team
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Old 02-25-2014, 11:14 PM   #2
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Pinout varies by year.

For '94-97, wherein the IAT sensor is integrated into the MAF assembly:



Wherein:

W/R = 12v
R/B = IAT
R/W = MAF (0-5v)
B/L = signal ground
B/LG = power ground






For '99-'05:



Wherein:

W/R = 12v
LG/B = MAF (0-5v)
B/L = ground
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Old 02-25-2014, 11:17 PM   #3
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https://www.miataturbo.net/megasquir...n-14166/page5/

I found this thread and put 12V to pin 5 and grounded pin 1 and used a DMM to read the voltage between 2 and 4 but am getting 0 volts.
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Old 02-25-2014, 11:23 PM   #4
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Quote:
Originally Posted by cyotani View Post
https://www.miataturbo.net/megasquir...n-14166/page5/

I found this thread and put 12V to pin 5 and grounded pin 1 and used a DMM to read the voltage between 2 and 4 but am getting 0 volts.
Re: the thread you linked to- know that there was a lot of misinformation floating around back then.

Re: your most recent test: Did you expect something other than 0v at the output with no airflow? (While the mechanical airflow meter in the '90-'93 cars scaled from 5v = no airflow to 0v = maximum airflow, rest assured that the hotwire MAF sensors in the '94-'05 cars scale "properly," wherein 0v = no airflow and 5v = maximum airflow.)
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Old 02-25-2014, 11:26 PM   #5
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Quote:
Originally Posted by Joe Perez View Post
Re: the thread you linked to- know that there was a lot of misinformation floating around back then.

Re: your most recent test: Did you expect something other than 0v at the output with no airflow? (While the mechanical airflow meter in the '90-'93 cars scaled from 5v = no airflow to 0v = maximum airflow, rest assured that the hotwire MAF sensors in the '94-'05 cars scale "properly," wherein 0v = no airflow and 5v = maximum airflow.)
Thanks for the help Joe!

I have a household fan and am measuring voltage with it off and with it blowing full blast into the MAF. I think that should be enough airflow to get a reading on my DMM but nada
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Old 02-25-2014, 11:41 PM   #6
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This is how I have it wired at the moment. red alligator is +11.55 from a battery and yellow is the battery negative terminal. 2nd pin from left is DMM ground and 4th from the left is DMM positive. (I made sure I have clean connections to the pin without the two adjacent alligator clips touching). Still no voltage regardless of airflow.



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Old 02-26-2014, 01:18 AM   #7
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This says far left is ecu ground (signal ground). but either way I still get 0 V regardless of airflow.

How to Test a 1995 Mazda Miata Mass Air Flow Sensor | eHow



Nice write up by the way Joe!

AFM Removal from the 1.6 liter Miata using eManage Ultimate
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Old 02-26-2014, 08:14 AM   #8
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Just a quick note as I hop on the train- you should probably ground both MAF grounds to the same point, and take your measurement relative to that combined ground.
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Old 02-26-2014, 10:41 AM   #9
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Quote:
Originally Posted by Joe Perez View Post
Just a quick note as I hop on the train- you should probably ground both MAF grounds to the same point, and take your measurement relative to that combined ground.
Okay, so the sensor ground and power ground should both go to the negative battery terminal and use a DMM to find the voltage from common ground to the sensor output 0-5V?
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Old 02-26-2014, 11:56 AM   #10
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Quote:
Originally Posted by cyotani View Post
Okay, so the sensor ground and power ground should both go to the negative battery terminal and use a DMM to find the voltage from common ground to the sensor output 0-5V?
That's the idea.
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Old 02-26-2014, 10:43 PM   #11
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Quote:
Originally Posted by Joe Perez View Post
That's the idea.

Worked like a charm! Thank you for the help good sir!

Electronic circuits is not my strong point. But now that I think about it common ground makes sense. I should known that one. Now on the PID portion. Should be a fun project.



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Old 02-27-2014, 12:44 AM   #12
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Quote:
Originally Posted by cyotani View Post
Worked like a charm! Thank you for the help good sir!


All that is visible must grow beyond itself, and extend into the realm of the invisible.
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