MAF Voltage Readings.

PonyGTrider · Oct 15, 2023

Hi there,
In my 90 GT twisted wedge, TFS intakes, TFS-1 cam, 19lb injectors, 65mm TB, and Cold Air Intake, I have a 70mm MAF tube and F2VF-12B579-AA sensor out of a 95 V6.
What do you think about those readings? They kind of look weird to me…

Idle - 0.951 Volts
20 mph - 1.935 Volts
40 mph - 0.179 Volts
60 mph - 1.904 volts

I know the stock MAF set up supposed to have:

Idle - 0.60 Volts
20 mph - 1.10 Volts
40 mph - 1.70 Volts
60 mph - 2.10 Volts

What the readings supposed to be on that 70mm MAF????

Would you agree that maybe that F2VF sensor is bad? And if that’s the case what would be the symptoms??? Perhaps higher fuel consumption or what else?

Anyone running that same MAF tube and sensor that had taken those measurements and if you can share them would be great!

Engine runs good I guess and idles good but I still have bad MPG, something like 9 -10 mpg and believe me I don’t have a lead foot.

Thanks for helping me on this one

PonyGTrider · Oct 15, 2023

PonyGTrider said:
Hi there,
In my 90 GT twisted wedge, TFS intakes, TFS-1 cam, 19lb injectors, 65mm TB, and Cold Air Intake, I have a 70mm MAF tube and F2VF-12B579-AA sensor out of a 95 V6.
What do you think about those readings? They kind of look weird to me…

Idle - 0.951 Volts
20 mph - 1.935 Volts
40 mph - 0.179 Volts
60 mph - 1.904 volts

I know the stock MAF set up supposed to have:

Idle - 0.60 Volts
20 mph - 1.10 Volts
40 mph - 1.70 Volts
60 mph - 2.10 Volts

What the readings supposed to be on that 70mm MAF????

Would you agree that maybe that F2VF sensor is bad? And if that’s the case what would be the symptoms??? Perhaps higher fuel consumption or what else?

Anyone running that same MAF tube and sensor that had taken those measurements and if you can share them would be great!

Engine runs good I guess and idles good but I still have bad MPG, something like 9 -10 mpg and believe me I don’t have a lead foot.

Thanks for helping me on this one

… By the way, NO ERROR CODES in case someone wondering.
I’ll read you with great interest

Noobz347 · Oct 15, 2023

I think measuring voltage against MPH is very arbitrary.

That said, a larger MAF is going to sample a smaller quantity of air inside of a larger opening. If the tune is not doing the math then the meter will have need to be scaled so that the appropriate amount of fuel is given for the sampled volume of air.

So, it stands to reason that voltage outputs are higher because the meter is sampling a smaller quantity of air and compensating for a larger overall mass of air (because the housing is larger).

So the number you listed appear to scale in the correct direction.

This line however, looks like an anomaly. It should be between those two other values:

PonyGTrider said:
40 mph - 0.179 Volts

PonyGTrider · Oct 15, 2023

Noobz347 said:
I think measuring voltage against MPH is very arbitrary.

That said, a larger MAF is going to sample a smaller quantity of air inside of a larger opening. If the tune is not doing the math then the meter will have need to be scaled so that the appropriate amount of fuel is given for the sampled volume of air.

So, it stands to reason that voltage outputs are higher because the meter is sampling a smaller quantity of air and compensating for a larger overall mass of air (because the housing is larger).

So the number you listed appear to scale in the correct direction.

This line however, looks like an anomaly. It should be between those two other values:

Understood, but as a comparison the two sets of voltage look so weird to me. The stock MAF the reading looks linear. More speed more volts. In the 70mm MAF does not show linearity at all the only numbers that make some sense are the Idle and 20mph, the 40mph reading supposed to be higher than the the 20mph and the 60 mph voltage supposed to be higher than the 40mph voltage. It is definitely contrary to the logic stated on the stock MAF setup.

I’ll do the measurements again insure repeatability.

Are this “faulty” readings related to too high fuel consumption???

Then what to do next?
Thank you all for the help

Noobz347 · Oct 15, 2023

I would get it tuned.

Kid wita 5oh · Oct 15, 2023

Bigger heads... Bigger flow, even at idle...

I just recently tested voltage between a pro-m and a stock MAF (19lb injs) both read EXACTLY the same at idle at 1.02-1.1v

PonyGTrider · Oct 15, 2023

Kid wita 5oh said:
Bigger heads... Bigger flow, even at idle...

I just recently tested voltage between a pro-m and a stock MAF (19lb injs) both read EXACTLY the same at idle at 1.02-1.1v

I got bad luck, I guess…

PonyGTrider · Apr 29, 2024

Hi all,
I'm just trying to alive this thread.
I was runing a test on 94-95 Mustang GT 70mm MAF. The readings don't seem normal to me if someone could give an opinion; I measure the voltage between pins C and D standing still and this is what I got:
IDLE speed 0.920 Volts DC
1,500 rpm 1.135 Volts DC
2,500 rpm 1.475 Volts DC

According to another forum the voltage at those rpm's supossed to be:
IDLE speed 0.9 - 1.0 Volts DC
1,500 rpm 1.4 Volts DC
2,500 rpm 1.8 Volts DC

Any thoughts, please?

KRUISR · Apr 29, 2024

PonyGTrider said:
Hi all,
I'm just trying to alive this thread.
I was runing a test on 94-95 Mustang GT 70mm MAF. The readings don't seem normal to me if someone could give an opinion; I measure the voltage between pins C and D standing still and this is what I got:
IDLE speed 0.920 Volts DC
1,500 rpm 1.135 Volts DC
2,500 rpm 1.475 Volts DC

According to another forum the voltage at those rpm's supossed to be:
IDLE speed 0.9 - 1.0 Volts DC
1,500 rpm 1.4 Volts DC
2,500 rpm 1.8 Volts DC

Any thoughts, please?

So your first set of readings are the 70mm MAF, what MAF is the second set - stock?

Your injectors, are they the OEM '90 injectors? If so, have they been cleaned?

DeathProof88 · Apr 29, 2024

I'm no expert but I've worked on Toyotas for years... I don't think I would base anything on speed and more on rpm and load.

Mustang5L5 · Apr 30, 2024

PonyGTrider said:
Hi all,
I'm just trying to alive this thread.
I was runing a test on 94-95 Mustang GT 70mm MAF. The readings don't seem normal to me if someone could give an opinion; I measure the voltage between pins C and D standing still and this is what I got:
IDLE speed 0.920 Volts DC
1,500 rpm 1.135 Volts DC
2,500 rpm 1.475 Volts DC

According to another forum the voltage at those rpm's supossed to be:
IDLE speed 0.9 - 1.0 Volts DC
1,500 rpm 1.4 Volts DC
2,500 rpm 1.8 Volts DC

Any thoughts, please?

I run the same MAF but don't have readings at this time. If i can think of it i can take some at some point. How are you measuring?

General karthief · Apr 30, 2024

See #7 here:

Help me create the "Surging Idle Checklist"

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...

www.stangnet.com

PonyGTrider · Apr 30, 2024

KRUISR said:
So your first set of readings are the 70mm MAF, what MAF is the second set - stock?

Your injectors, are they the OEM '90 injectors? If so, have they been cleaned?

Yes first readings are from the 70mm MAF the second redings are from the 55mm MAF. I just serviced the injectors and ther are in perfect conditions. This comparisson of readings are intended to findout if it has anything to do with my poor Miles Per Gallon issue

Mustang5L5 · Apr 30, 2024

Here's some published data

Got it from here.

MAF Transfer Curves / EFIDynoTuning

PonyGTrider · Apr 30, 2024

Mustang5L5 said:
Here's some published data

Got it from here.

MAF Transfer Curves / EFIDynoTuning

Thank you, I’m not sure how (If there is a way) to calculate or translate my figures to find a flow rate…

Mustang5L5 · May 1, 2024

PonyGTrider said:
Thank you, I’m not sure how (If there is a way) to calculate or translate my figures to find a flow rate…

I think the main take-away is that it's not going to be similar readings. ALso, it's one data point and i'm not sure of their source of the data, so take it with a grain of salt.

Kinda one of those times you wish EEC-IV could output the same sort of data OBD2 can, so you can look at things like fuel trims and o2 sensor voltage swings.

Swap your stock MAF in. You'll lose a bit of power but you can see if you notice any significant difference in fuel economy.

CassieL · Jun 2, 2024

PonyGTrider said:
Hi all,
I'm just trying to alive this thread.
I was runing a test on 94-95 Mustang GT 70mm MAF. The readings don't seem normal to me if someone could give an opinion; I measure the voltage between pins C and D standing still and this is what I got:
IDLE speed 0.920 Volts DC
1,500 rpm 1.135 Volts DC
2,500 rpm 1.475 Volts DC

According to another forum the voltage at those rpm's supossed to be:
IDLE speed 0.9 - 1.0 Volts DC
1,500 rpm 1.4 Volts DC
2,500 rpm 1.8 Volts DC

Any thoughts, please?

What method are you using to measure?

PonyGTrider · Jun 2, 2024

CassieL said:
What method are you using to measure?

I'm using a DVM taking measurements at idle, at 1,500 RPM, and at 2,500 RPM. Also another method: At idle, at 20 MPH, at 40 MPH, and at 60MPH. Al the readings do not correlate and it is all over so I don't know of another wau to do that.

CassieL · Jun 2, 2024

Dvm isn't accurate for that, they use average voltage. A scope will be more accurate .
A 90' doesn't support live data and that's what we usually use to see what the computer sees.
As long as you're not getting trouble codes then the computer is fine with what it's getting.
Usually with a ford we want under a volt at idle, 1-2 volts between 1k and 3k above 2 v above 3k

CassieL · Jun 2, 2024

These are data scans of a 95 mustang ecu used for the maf conversion in my truck.
You can see how the maf, tps, o2 and rpm all move with each other.

MAF Voltage Readings.

PonyGTrider

PonyGTrider

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

PonyGTrider

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Kid wita 5oh

I'm definitely not in the original hole

PonyGTrider

PonyGTrider

KRUISR

DeathProof88

Active Member

Mustang5L5

That is…until I whipped out my Bissell

General karthief

wonder how much it would cost to ship you a pair

Help me create the "Surging Idle Checklist"

PonyGTrider

Mustang5L5

That is…until I whipped out my Bissell

PonyGTrider

Mustang5L5

That is…until I whipped out my Bissell

CassieL

Active Member

PonyGTrider

CassieL

Active Member

CassieL

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MAF Voltage Readings.

Stangnet Facilities Maint Tech... Er... Janitor

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I'm definitely not in the original hole

Active Member

That is…until I whipped out my Bissell

wonder how much it would cost to ship you a pair

That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

Active Member

Active Member

Active Member

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