Does anyone have MAF sensor wiring diagram.

[Fk8_tuning_development]

Hello I am looking for MAF sensor wiring diagram for fk8. Currently the diagrams are not available in Mitchell yet. I’m looking to move to an external iat sensor.
Using separate sensor prevents any heat soaked into the entire MAF sensor giving false readings. BMW guys usually do this and for very good reason.

The MAF sensor is specific to fk8 and Honda clarity.
being it’s actually 5 wire hitachi sensor and not Honda or Bosch it might match another diagram.

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[Centripetal]

Currently the diagrams are not available in Mitchell yet.

Where did you check in Mitchell?

 

[shadow]

Hello I am looking for MAF sensor wiring diagram for fk8. Currently the diagrams are not available in Mitchell yet. I’m looking to move to an external iat sensor.
Using separate sensor prevents any heat soaked into the entire MAF sensor giving false readings. BMW guys usually do this and for very good reason.

The MAF sensor is specific to fk8 and Honda clarity.
being it’s actually 5 wire hitachi sensor and not Honda or Bosch it might match another diagram.

Cross reference the ecu pins above and the ones below. My guess is it is the BLK/YEL & PUR wires. Terminals 52 & 63 below or 4 & 5 above.

You may want to test if you got the right terminals by a test method in the STI FSM. Of course Ohm readings may be different.

BTW, I went to an external IAT and speed density tuning in my STI. I don't run a MAF anymore. Have fun with tinkering!

 

[Fk8_tuning_development]

Cross reference the ecu pins above and the ones below. My guess is it is the BLK/YEL & PUR wires. Terminals 52 & 63 below or 4 & 5 above.

You may want to test if you got the right terminals by a test method in the STI FSM. Of course Ohm readings may be different.

BTW, I went to an external IAT and speed density tuning in my STI. I don't run a MAF anymore. Have fun with tinkering!

m
Thank you this is helpful. We can’t run speed density. Not on hondata. The hitachi MAF iat has been known to have this problem.

What’s helpful and odd is the numbering.
5 being iat lines up with the hitachi style being correct but the diagram says 3.
It’s my understanding the hitachi Iat sensor uses #5 to go back to the ecu but requires signal from #3 into the sensor. 2005 mustang uses same sensor and has a relocation kit but I can’t seem to get solid confirmation on what is what. I’ve seen other hitachi say #1 is iat.

Well it’s either going to be 3 and 5 or 1 and 3. Ohm meter should help
This is going by

 

[shadow]

m
Thank you this is helpful. We can’t run speed density. Not on hondata. The hitachi MAF iat has been known to have this problem.

What’s helpful and odd is the numbering.
5 being iat lines up with the hitachi style being correct but the diagram says 3.
It’s my understanding the hitachi Iat sensor uses #5 to go back to the ecu but requires signal from #3 into the sensor. 2005 mustang uses same sensor and has a relocation kit but I can’t seem to get solid confirmation on what is what. I’ve seen other hitachi say #1 is iat.

Well it’s either going to be 3 and 5 or 1 and 3. Ohm meter should help
This is going by

#3 is +12V.

i think #2 is ground, #3 is 12V. This supplies power to the hot wire. #1 airflow signal output. #4 IAT sensor output & #5 supplies IAT +5V.

*edit*
Take this with a grain of salt, I'm just trying to figure it out.

 

[Centripetal]

m
Thank you this is helpful. We can’t run speed density. Not on hondata. The hitachi MAF iat has been known to have this problem.

Yeah, that's true because the system uses a MAF sensor...
A Speed Density Sensor measures air velocity with mechanical movement.
A MAF Sensor measures air velocity with a hot wire wire.

What’s helpful and odd is the numbering.
5 being iat lines up with the hitachi style being correct but the diagram says 3.
It’s my understanding the hitachi Iat sensor uses #5 to go back to the ecu but requires signal from #3 into the sensor. 2005 mustang uses same sensor and has a relocation kit but I can’t seem to get solid confirmation on what is what. I’ve seen other hitachi say #1 is iat.

Well it’s either going to be 3 and 5 or 1 and 3. Ohm meter should help
This is going by

MAF sensor pinout

1 - AFM signal/measurement
2 - signal ground - nice clean ground with little noise on it
3 - 12V - Power supply for the wire
4 - signal power - Clean reference voltage for the sensors
5 - Temperature signal/measurement

You measure Resistance between 5 and 2 for Temperature
You measure Voltage between 1 and 2 for Air Flow. To do this you'd need to apply a voltage to 3 and 4.

 

[shadow]

Yeah, that's true because the system uses a MAF sensor...
A Speed Density Sensor measures air velocity with mechanical movement.
A MAF Sensor measures air velocity with a hot wire wire.


MAF sensor pinout

1 - AFM signal/measurement
2 - signal ground - nice clean ground with little noise on it
3 - 12V - Power supply for the wire
4 - signal power - Clean reference voltage for the sensors
5 - Temperature signal/measurement

You measure Resistance between 5 and 2 for Temperature
You measure Voltage between 1 and 2 for Air Flow. To do this you'd need to apply a voltage to 3 and 4.

Speed density uses manifold absolute pressure (MAP) and rpm to compute fuel.
Mass Air Flow uses mass of air with a hot wire, as you said.

In the STI, very creative programmers use the MAP, IAT and rpm to compute the the MAF value using the Ideal Gas Law. The result is the computed MAF which is fed into the ECU. It is all software implemented. Our cars can do that if someone can do the programming.

You are right 2 & 5 make more sense for temperature.

 

[Centripetal]

Speed density uses manifold absolute pressure (MAP) and rpm to compute fuel.
Mass Air Flow uses mass of air with a hot wire, as you said.

In the STI, very creative programmers use the MAP, IAT and rpm to compute the the MAF and input that into the ECU. It is all software implemented. Our cars can do that if someone can do the programming.

You are right 2 & 5 make more sense for temperature.

I think I was assuming some context: the intake. There are a couple ways to do speed density measurements, which is why I said mechanical movement.
Also, MAP means Manifold Absolute Temperature, which is not the context I was assuming. Consequently, the FK8 does have a speed density setup on the manifold, MAP and Temperature. I don’t know why you’d want to use that. MAF is more accurate.

 

[shadow]

I think I was assuming some context: the intake. There are a couple ways to do speed density measurements, which is why I said mechanical movement.
Also, MAP means Manifold Absolute Temperature, which is not the context I was assuming. Consequently, the FK8 does have a speed density setup on the manifold, MAP and Temperature. I don’t know why you’d want to use that. MAF is more accurate.

Sorry, I wasn't wanting to implement SD on the FK8. I was showing the process of how I got the IAT wires on the MAF and why I did it.

I agree, MAF is definitely more accurate and to some extent, adjusts to the modifications. However, once you exceed the sensor's limit and go to a bigger housing, tuning gets more complicated. SD gets around that complication.

For SD, I was thinking along these lines when using the term MAP:

https://en.wikipedia.org/wiki/MAP_sensor

 

[Centripetal]

Sorry, I wasn't wanting to implement SD on the FK8. I was showing the process of how I got the IAT wires on the MAF and why I did it.

I agree, MAF is definitely more accurate and to some extent, adjusts to the modifications. However, once you exceed the sensor's limit and go to a bigger housing, tuning gets more complicated. SD gets around that complication.

For SD, I was thinking along these lines when using the term MAP:

https://en.wikipedia.org/wiki/MAP_sensor

Yep, still a MAP sensor... MAP sensor can exceed the range just like MAF. See turbo added to NA car.

 

[seselectronics]

Why go so complex? You can do cooling mods and have excellent results, I don't have heat soak issues , I live in Florida the weather is extremely hot and my car is daily, a lot of slow traffic and city driving, I usually have 3 to 5 degrees above ambient temps on the intake cruising and around 7 to 10 degrees in slow traffic , also you can tweak the tuning and change the parameters for avoiding temperature corrections if you want. For other side if you cheat the sensor it doesn't mean the high intake temps are not there, the rest of the intake system ( intercooler, intake manifold ) will not performs with efficiency .

 

[FK8_K20c1]

Why go so complex? You can do cooling mods and have excellent results, I don't have heat soak issues , I live in Florida the weather is extremely hot and my car is daily, a lot of slow traffic and city driving, I usually have 3 to 5 degrees above ambient temps on the intake cruising and around 7 to 10 degrees in slow traffic , also you can tweak the tuning and change the parameters for avoiding temperature corrections if you want. For other side if you cheat the sensor it doesn't mean the high intake temps are not there, the rest of the intake system ( intercooler, intake manifold ) will not performs with efficiency .

When it comes to cooling mods this guy is a genius. I have not seen anyone heatsoak temps under control like this guys car. He knows his stuff.

 

[Fk8_tuning_development]

Where did you check in Mitchell?

Shop key has it. I share it with another shop in return I diagnose the cars he can’t. It’s either listed as michell or snap on but it’s the same stuff. I have a feeling it needs to be updated.

Yeah, that's true because the system uses a MAF sensor...
A Speed Density Sensor measures air velocity with mechanical movement.
A MAF Sensor measures air velocity with a hot wire wire.


MAF sensor pinout

1 - AFM signal/measurement
2 - signal ground - nice clean ground with little noise on it
3 - 12V - Power supply for the wire
4 - signal power - Clean reference voltage for the sensors
5 - Temperature signal/measurement

You measure Resistance between 5 and 2 for Temperature
You measure Voltage between 1 and 2 for Air Flow. To do this you'd need to apply a voltage to 3 and 4.

This response is to a few comments.

This is what I have found on another hitachi sensor on 2 different vehicles. I have a power probe electrical tester. #5 should be iat return to ecu and it makes sense cause looking into the sensor you wouldn’t put the MAF reading behind the iat it would block signal.

Measuring between 5 and 2 will not give you iat resistance. Iat doesn’t use a ground it uses 5volt input from #4 and signal out is #5. Iat does not require a ground wire. You ground out a resistor it won’t read. An iat is only a resistor. The electrical diagram #5 shows resistor symbol. Anything that shows that is a sensor return to ecu. #4show 5v supply.

MAF requires 12 volt to heat the sensor. The ground is for the circuit inside the sensor while the iat is seperate internally. Old MAF sensors only used three wires..

I also found this it’s only 2 dollars but cause shipping it costs 12. It’s not a very tight fit but as long as I stick it to the housing first it should seal creating a barrier to help. It’s k&n 09069. Beyond that wrapping the MAF housing with firewall silencer/heat barrier helps.

Speed density is when an engine functions on intake temp and map sensor. Map sensors only monitor pressure and have no way of measuring velocity. Speed density is harder to create consistent fueling compared to MAF tune. New 5.0 mustangs use MAF only.

 

[turbociv910]

Curious to what/how you think you're going to improve upon by moving the temp sensor.

A few pats on the gas after sitting still and the maf temp is ambient on my ECU.

The air box temp does raise when idling and sitting still... i put a sensor IN the air box.. Any speed above 30 mph i see an almost ambient temperature from the ram/ snorkle effect... from my logging.

MY biggest issue is the manifold temperature. It is the real issue. It raises to 15 above inlet temps pretty much no matter what. The Coolant on the throttle body is my suspect.

 

[Centripetal]

Shop key has it. I share it with another shop in return I diagnose the cars he can’t. It’s either listed as michell or snap on but it’s the same stuff. I have a feeling it needs to be updated.

Why do we need this information? Is my point

This response is to a few comments.

You have no idea what you are talking about. I don't even know where to start.

This is what I have found on another hitachi sensor on 2 different vehicles. I have a power probe electrical tester. #5 should be iat return to ecu and it makes sense cause looking into the sensor you wouldn’t put the MAF reading behind the iat it would block signal.

I've been professionally working with electronics (repairing and designing) since 1998 and I have no idea what "power probe" and "electrical tester" is. Possible things you could mean: Power Supply, Digital Multi Meter, Power Meter.

Measuring between 5 and 2 will not give you iat resistance. Iat doesn’t use a ground it uses 5volt input from #4 and signal out is #5. Iat does not require a ground wire. You ground out a resistor it won’t read. An iat is only a resistor. The electrical diagram #5 shows resistor symbol. Anything that shows that is a sensor return to ecu. #4show 5v supply.

Wrong in so many ways. Did you measure it? I did. The temperature is measured by using a resistor divider network. With the top of the divider in the ECU using the clean 5V. If it was using the 5V going to the sensor/resistor, the change in resistance would result in no change in voltage because there is no potential difference. That's circuits 101. I suggest you google thermistor circuit if you want a better understanding how it works. I'd get into how the MAF measures flow but if you don't understand resistor dividers, you'll have no chance at Wheatstone Bridge.

MAF requires 12 volt to heat the sensor. The ground is for the circuit inside the sensor while the iat is seperate internally. Old MAF sensors only used three wires..

Yep. That's what I said. It's for heating the wire.
Old sensors probably used chassis for ground, which will make the sensor reading very noisy. Ground loops are like antennas. The MAF housing is not grounded in the FK8. Easy way to test this is remove the connector and measure the resistance between one of the MAF bolts and chassis. It will be in the mega ohm range.
It is true they could be current return measurements but I'm not going to get into why they would not use those.

I also found this it’s only 2 dollars but cause shipping it costs 12. It’s not a very tight fit but as long as I stick it to the housing first it should seal creating a barrier to help. It’s k&n 09069. Beyond that wrapping the MAF housing with firewall silencer/heat barrier helps.

This is kind of neat. However, I'd be concerned the thickness would create an error in measurements. When installed what's the thickness? Not sure that's the biggest contributor to heat issues.

Speed density is when an engine functions on intake temp and map sensor. Map sensors only monitor pressure and have no way of measuring velocity. Speed density is harder to create consistent fueling compared to MAF tune. New 5.0 mustangs use MAF only.

As I mentioned many times in reply to one of your posts, pressure difference is proportional to air flow. The pressure measurement infers velocity, which has error. MAF is better.

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