Does anyone have MAF sensor wiring diagram.

[shadow]

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.

I agree with this. There is no potential voltage difference between 4 and 5. There will be no current flow and therefore, no voltage drop across the resistor.

 

[turbociv910]

Why do we need this information? Is my point


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


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.


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.

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.


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.


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.

In his defense, a power probe Is an automotive tool to identify voltage or ground on unknown wires. You can also apply a 12v or gnd to wires for resting/diag. I've actually have one.

 

[Centripetal]

In his defense, a power probe Is an automotive tool to identify voltage or ground on unknown wires. You can also apply a 12v or find to wires for resting/diag. I've actually have one.

Dang, I totally forgot they were called that. You are right. They don't even reference such equipment in service manuals anymore. At least not the ones I've seen. It's a horrible name as you can't really probe for power (as in Watts).

 

[seselectronics]

Just answering a few comments,
1) Its going to be very difficult to replace the maf sensor for other different , might you have the same signals but not the same values, is like you trying to tap in to the water temp sensor and hookup an external gauge, it will read any crap, because the signal is the same ( resistance variation value in ohms) but in one case with higher temps the resistance increase and for the other case high temps the resistance decrease, or just simple as the reference value is different in that case one sensor with read x value at certain temperature and with other with read completely off .

2)I read another comment regarding higher temps at the intake manifold, this is not because the heater for the throttle body, I have this bypassed and the temps are slightly better when you are not with boost , but still getting around 10 to 13 degrees above ambient temps, the reason is simple, the turbocharger itself no matter what it going to heat up very bad.. you have the exhaust gases going in to the turbine more than 600 C just driving around, that temperature get transfer to the compressor housing , all that heat travel trough the intercooler and piping, the intercooler won't do anything because the speed of the air is not enough for get in contact with the fins that is why when you have boost the temps go lower.

 

[seselectronics]

All the MAF or MAP sensor has a thermistor for read temperature, is just a variable resistor, mostly cases works with 5 v in one leg and the other is the signal output , if you don't plug a resistor could be 1 k to GND is no way you can read anything with a multimeter.

 

[seselectronics]

Is very cool what OP is doing and I’m not discourage to anyone to try stuff I do all the time , just I wrote information might be useful .

 

[Fk8_tuning_development]

Why do we need this information? Is my point


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


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.


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.

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.


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.


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.

Way to bash someone when they are trying to keep it simple. You complicated it fir no reason. The sensor itself I was taking about!! . all I said was the ecu calculates off voltage change that comes out of the temp sensor which varies by temp. Yes I know it’s a thermistor. Total overkill man. The actual thermistor itself on a car is only two wires. Resistance does change with temp and testing checking resistance at same temperatures on different sensor is how we verify iat relocation would work. No one wants an entire electrical breakdown. Any one buying this doesn’t need all the extra info.



Speed density you said “map measures velocity”
People don’t get that they’ll think it’s nit a pressure sensor. Speed density is only a calculation. Density is measured by map and iat. Between the volumetric efficiency table and mep pressure speed/velocity is calculated. So yes in a way map measure velocity if you look at it that way. Saying it the way you said it before it will only confuse people. Map by itself can not. Again overcomplicating it for no reason.

Car ect temp sensor functions the same way. By saying all that you’ll confuse the crap out of the general public then they’ll thinking relocating the iat is a whole giant ordeal.
Great your smart. The world knows now. People respond to keeping it simple. I’ve succeeded very well simplifying things for people. Customers don’t car when a car is broke how the car works. They want to know it works when your done:
99 percent of people just want to know it works and if it improves it how much.

You over complicated it. The reason the wire is Piggy backed and not completely disconnected is for the circuit. I think you really took my wording out of context. It’s not meant to be text book educational.

Knowing how a circuit board vs engine performance are two different worlds that share some things. Your explanation will be different than mine.

 

[Centripetal]

Way to bash someone when they are trying to keep it simple. You complicated it fir no reason. The sensor itself I was taking about!! At no point did I start taking how the ecu worked. all I said was the ecu calculates off voltage change that comes out of the temp sensor which varies by temp. Yes I know it’s a thermistor. Total overkill man. The actual thermistor itself on a car is only two wires. Resistance does change with temp and testing checking resistance at same temperatures on different sensor is how we verify iat relocation would work. The sensor itself only needs the 5volt input to work No one wants an entire electrical breakdown. Any one buying this doesn’t need all the extra info.
Voltage output back to the ecu absolutely charges by temp. That’s why my snap on scan tool reads voltage directly off the sensor. Then in order to diagnose it we verify voltage at the sensor output to confirm wiring is good when we have a fault that’s it. Yes I’ve measured it by the sensor only. No we don’t apply 5volts to it to test it cause we can control amperage like an ecu can. Iat relocation wouldn’t be so easy if all that circuitry was in it.

We do however apply 12 volts to test a MAF out the car. Totally different scenario.


Speed density you said “map measures velocity”
People don’t get that they’ll think it’s nit a pressure sensor. Speed density is only a calculation. Density is measured by map and iat. Between the volumetric efficiency table and mep pressure speed is calculated. So yes in a way map measure velocity if you look at it that way. Saying it the way you said it before it will only confuse people. Map by itself can not. Again overcomplicating it for no reason.

Car ect temp sensor functions the sane way. No extra circuitry within the sensor. By saying all that you’ll confuse the crap out of the general public then they’ll thinking relocating the iat is a whole giant ordeal.
Great your smart. The world knows now. People respond to keeping it simple. I’ve succeeded very well simplifying things for people. Customers don’t car when a car is broke how the car works. They want to know it works when your done:
99 percent of people just want to know it works.

There is nothing inside this sensor except what you see. No circuits.

My first post was very simple 76 words explaining the pinout.
It took you 245 words to allege said pinout was wrong.
My follow up to said ramblings was 68 words for explaining how your analysis was wrong.
The post I'm replying to now was 463 words.
Who's complicated...

As for the senors not having a circuit. Thermistor is part of the circuit. For the air-flow part, it most likely has a wheatstone bridge and instrumentation amplifier. With ECU and sensors power combined you have... a... CIRCUIT!!!

In regards to being smart, I can't be that smart because I keep wasting time replying to insanely wrong posts.

 

[shadow]

The voltage divider circuit is inside the ECU. See the red circle.

So, my guess is one terminal of the external IAT sensor gets tapped into #2 (gray wire) for ground reference. Next cut #5 (purple wire) and connect the ECU side of it to the other terminal of the sensor.

Now you either need a program that can calibrate the new external IAT sensor or you need an IAT with the exact resistance characteristics of the Hitachi MAF's IAT sensor.

 

[Fk8_tuning_development]

Let me start by saying I thought this would be like mustang MAF but it has 6 wires with the divider being 100 percent in the ecu. My brain has been on overload.


5 going through 4 goes thermistor ground and resistor with the ground In between the thermistor and resistor.

Just using 5 and 2 like someone suggested cuts out 4 which is part of the circuit. Why else would the thermistor be on 4 also. this verified by pinning and off the thermistor itself to the pins. Thermistor connects to pins 4-5 and 2-5 .

I checked this 5 times to make sure I wasn’t crazy. The ohm drop on 4-5 and 5-2 is identical drop literally just adding 9400 between 4-5.
it will need an external resistors as part of the divider set up most likely in order to make an iat relocation work.

ill have find a way to take the MAF I am using completely apart to see what they are doing.

Vcc is reference voltage so it can be removed from equaton

 

[Centripetal]

Let me start by saying I thought this would be like mustang MAF but it has 6 wires with the divider being 100 percent in the ecu. My brain has been on overload.


5 going through 4 goes thermistor ground and resistor with the ground In between the thermistor and resistor.

Just using 5 and 2 like someone suggested cuts out 4 which is part of the circuit. Why else would the thermistor be on 4 also. this verified by pinning and off the thermistor itself to the pins. Thermistor connects to pins 4-5 and 2-5 .

I checked this 5 times to make sure I wasn’t crazy. The ohm drop on 4-5 and 5-2 is identical drop literally just adding 9400 between 4-5.
it will need an external resistors as part of the divider set up most likely in order to make an iat relocation work.

ill have find a way to take the MAF I am using completely apart to see what they are doing.

Vcc is reference voltage so it can be removed from equaton

Before you reply, please keep this in mind: I AM TRYING TO HELP YOU.

My measurements at 20 C:
2,5 ~= 2.6k Ohm
4,5 ~= 9.4K Ohm

With risk of sounding complicated...

I think I know what they might be doing. The one closest to the camera is the NTC.

They could be using combination two thermistors—I would guess NTC and PTC—to get more accurate temperature measurements. One of the issues with using a single thermistor for a wide range (-40C to 85C) is some of your area of measurement will have more error.

Another thing they might be doing is using that temperature measurement on the sensor for compensation and/or calculations.

EDIT: I missed the most obvious answer about the resistance between 4,5. The current flows: into pin 4 => into the wheatstone bridge => through resistors in wheatstone bridge => through ground => through thermistor => pin 5

You don't need to take it apart to see what going on. If your fancy snap-on tool can measure the voltage (IAT2) and temperature (IAT2), all we'll need is a few data-points to determine the circuit.

If you can provide the voltage and temperature measurements for 20C, 40C and 60C. We can use those measurements to figure out the circuit. The same can be done for the MAF. IIRC, the "wire", is 100 Ohms.

On Hitachi's website, they say they can program it for any range of flow. I am speculating there might be smarts in the sensor. What they might also do is just change that metal plate for different flow ranges.

Here's something from Hitachi I recently came across.

These complications are things we engineers do to make techs lives difficult. I was a tech before an engineer

How about some community teamwork?

 

[seselectronics]

Before you reply, please keep this in mind: I AM TRYING TO HELP YOU.

My measurements at 20 C:
2,5 ~= 2.6k Ohm
4,5 ~= 9.4K Ohm

With risk of sounding complicated...

I think I know what they might be doing. The one closest to the camera is the NTC.

They could be using combination two thermistors—I would guess NTC and PTC—to get more accurate temperature measurements. One of the issues with using a single thermistor for a wide range (-40C to 85C) is some of your area of measurement will have more error.

Another thing they might be doing is using that temperature measurement on the sensor for compensation and/or calculations.

You don't need to take it apart to see what going on. If your fancy snap-on tool can measure the voltage (IAT2) and temperature (IAT2), all we'll need is a few data-points to determine the circuit.

If you can provide the voltage and temperature measurements for 20C, 40C and 60C. We can use those measurements to figure out the circuit. The same can be done for the MAF. IIRC, the "wire", is 100 Ohms.

On Hitachi's website, they say they can program it for any range of flow. I am speculating there might be smarts in the sensor. What they might also do is just change that metal plate for different flow ranges.

Here's something from Hitachi I recently came across.

These complications are things we engineers do to make techs lives difficult. I was a tech before an engineer

How about some community teamwork?

The top one looks more like a diode , but jus judging by the capsule , many other systems use a diode for measure temperature also

 

[Centripetal]

The top one looks more like a diode , but jus judging by the capsule , many other systems use a diode for measure temperature also

It does look like a diode. It could be; Diode is a great way to measure temperature. Although I switched the leads and it read the same.

Sponsored