Cant reach 255 MAF reading

[6SENSE]

Why is it that I can never reach a MAF reading of 255? I usually only get around 240 max. Am I really not flowing the air, is the car that much out of tune, or is it possible that the MAF is junk and just cant go any higher?

 

[turbo6x2]

Could be the last one.

 

[cool 84]

Could be you're not flowing enough air or the meter won't go any higher. I have a GM 87 MAF and it hits 254 at 10psi boost but doesn't go any higher even at 20psi. If you're trapping ~102+mph you should peg the meter. If you're running a non GM meter that's probably the problem. If you're running the 84 meter it pegs easily.

 

[fireberd350]

how do u measure that?

 

[TType84]

the maf is broken

stock cars can read 255, thats why we tune with fuel pressure..

 

[cool 84]

I know for a fact a stock hotair with an 87 MAF won't peg the meter. It MIGHT peg the hotair meter, not sure. Even an 87 won't peg the meter. Usually all it takes is turning the boost up a few psi and it's there but not a stocker.

 

[fireberd350]

HOW DO YOU READ THESE VALUES???? scanmaster?

 

[TType84]

open exhaust will do it, a K&N is required

youre right, showroom stock shouldnt.

i assume most all cars have a good exhaust anda K&N atleast though..

 

[fireberd350]

Originally posted by fireberd350
HOW DO YOU READ THESE VALUES???? scanmaster?

 

[6SENSE]

Originally posted by fireberd350
HOW DO YOU READ THESE VALUES???? scanmaster?

Yes, any scantool should give you MAF values.

 

[6SENSE]

Thanks for the replies everyone.
Take a look at my mods. Especially after resolving my wiped cam, 0 lifter preload, valve spring, low compression, and countless other issues, I KNOW I am flowing some air now. I just looked at some of my test runs I did on the highway last night on TLink. The majority of my WOT MAF values were in the 220s and 230's. My max was 243 w/ 18-20 psi boost.

Here is how the help section of the TLink program explained Mass Air Flow: This field is determined from the Mass Air Flow (MAF) Sensor input to the ECM and is reported in grams/second. The MAF is located in the inlet hose close to the radiator. Normally this value will be 4-7 gms/sec at idle and will approach 255 gms/sec at WOT. Even with the car off and key on, this value will show 2-4 gms/sec. The WOT value will vary depending on state of tune, how much boost and air density. Normally a 12 second car will show 255 gms/sec at WOT with 19-20 psi of boost. The actual air flow is greater than that shown, because the MAF value is factored
Does this mean that my car is not tuned to run 12s and that the values Im getting are correct? Or do I need to be looking into getting a translator and ImpalaSS MAF? What does the ECM do with the MAF readings? Adjust the fuel curves? If the readings are low (i.e. from a MAF that doesnt read high enough) how does it affect performance?
I guess thats alot of questions, but I think you guys/gals no what Im getting at. Thanks.

 

[cool 84]

A MAF that doesn't max out (assuming you're flowing enough air to max it out) will affect performance. This could better be answered in the chip section, I don't know a whole lot. From what I know it's a factor in the PE mode which affects fueling and timing. A chip like the Max Effort is adjustable so even if you don't have a maf that will max out you can lower the number it sees as max. As far as I know the MAF measures airflow into the engine and is one major factors in the calculation fuel and spark also based on other things like rpm, TPS, etc. The 02 sort of checks the calculation. If it's bad and the reading is off it can affect idle, drivability, and WOT. Do you have any timeslips, especially what mph you run? Again, you might want to check other areas of the board, I could be wrong on some points.

 

[6SENSE]

Originally posted by cool 84
A MAF that doesn't max out (assuming you're flowing enough air to max it out) will affect performance. This could better be answered in the chip section, I don't know a whole lot. From what I know it's a factor in the PE mode which affects fueling and timing. A chip like the Max Effort is adjustable so even if you don't have a maf that will max out you can lower the number it sees as max. As far as I know the MAF measures airflow into the engine and is one major factors in the calculation fuel and spark also based on other things like rpm, TPS, etc. The 02 sort of checks the calculation. If it's bad and the reading is off it can affect idle, drivability, and WOT. Do you have any timeslips, especially what mph you run? Again, you might want to check other areas of the board, I could be wrong on some points.

Havent been able to make it to the track yet this year. Last year my best was 14.2@96 w/ 2.2 60ft on street tires and 93 octane, no alky. That was with a few engine problems, including a bad cam.
Maybe I'll try my brothers MAF and see if there is any change. I also have a few '84 MAFs sitting around (mine is a '87 GM unit).

 

[turbo6x2]

Try the swap first and see what you get. That will determine if you maf is on it's way out. I know there was a huge topic on this last year, try a search because it was very well explained and will give you some better answers.

 

[Mr.Buick]

MAF readings

Check to make sure the throttle plate is wide open when the gas pedal is flat on the floor.

 

[Lee_Burough]

If the MAF reading is the same or similar with a known good MAF, try disconnecting the air filter and see if the flow changes....Could be a clogged filter.

 

[alb84]

I get the feeling it is just out of spec, and it really doesn't matter. With your trap speed, the maf is pegged, and you should tune from the point that it pegs it. It could be a slight difference in reference voltage, or any # of other variables. As long as it reads consistently from low to high you can tune with it. It's not worth replacing if its just a little out of spec. Enjoy! Later.....Danny