high maf voltage????

If you have a Cold Air Induction, replace it with the stock airbox and flat panel filter.
If no CAI, place a piece of window screen at the entrance of the MAF opening. The first Mass Air cars had a MAF with a screen. It helps reduce turbulence in the MAF.

I would make sure your probing the correct return signal voltage. If your idle is below 800, then it should be around a volt. All it's doing is measureing flow.

With the IAC 100% open the idle would be like 2500. So no, it's not.

I think I mentioned on your other thread that I would not have sweat the MAF voltage (based upon my experience and tweaking the curve with an F2 MAF). There are myriad variables involved with idle MAF readings, so there's not a precise answer.

There is nothing that says you can't post threads on every Mustang forum on the internet. Some would argue that's the smart angle. However, alienating the folks here probably won't help with any future threads.

Good luck to you.

Maybe someone else somewhere else is Mr Know-It-All, but I'm not. I am still learning things about these cars because every one of them is a little different.

If you didn't find your answer here, that's life. Count yourself blessed that you got an answer somewhere else. Time will tell if the answer you got was worthwhile...

just a thought, but if you had a K&N filter on the car you may have oil on the maf wire. try some mass air cleaner on there, then see if its any lower once it dries

86turbo said:

Hissin- I told jrichker in another thread your input (you woudn't sweat the voltage.) It seemed like you were unsure otherwise i would have expected you to say YES its fine.....thats all.

I'm not alienating anyone, I was just saying i'm surprised nobody could really comment on my situation. I was just looking for a yes or no.....

Maybe I should have posted this in the tuning section??

87AODGT- thats an interesting theory! This is only k&n ive ever used and i dont even think its oiled, someone probably washed it off long ago with water or something while cleaning it up. This may be a dumb question but does it need the oil to help with flow? I have a bizarre "sucking" noise coming from my air cleaner while my car is idling.

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This was kind of my point however. We all have different experiences and every car is different. Maybe JRichker worked on a car where having the MAF voltage over 0.60V at idle lead to issues, whereas I have had mine as high as 1.20 V and noted no drivability issues. Point being, every one has had different experiences and every car is different, ergo no one can say definitively that something is or isn't causing an issue. I sure would not (read my old posts - I seldom say anything in a definite way when it comes to drivability or tuning issues, as I think people that do that are often ill advised).


The air filter uses a dedicated cleaner and oil. The oil helps attract debris, and a little debris in the media helps it filter better (read: you dont want to run the filter without oil). The cleaner and oil kits used to be about 10 bucks - I'd buy one and clean and lube the filter properly if there are any doubts as to what a PO did (or grab a buddy's kit if you know someone with an oiled filter).

Cleaning or inpsecting the MAF wires is part of regular maintenance IMHO, especially on PCV cars. It takes a few mins and security torx bit (Security T20 IIRC) to check it.

Good luck.

86turbo said:

gotcha. The guy at pro-m tried to explain that when you upgrade your engine to make more power it will be sucking in more air and expelling more exhaust. Since its acting like a more efficient air pump per say it will be sucking in my air at idle hence the higher maf voltage

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The problem with this theory and idle is that at idle speeds, the engine ingests a low volume of air/fuel. The manifold vacuum is high because the throttle is closed. High vacuum means low airflow: at WOT with max airflow, vacuum drops down to 1” or less. Typical vacuum ranges from 16”-18” at 650-725 RPM. With a small volume of air passing though the MAF, the voltage should be low. Only enough air volume is passed to maintain engine RPM at 800 RPM or less.

It takes a fixed volume of air to maintain idle speed. That volume of air does not change with the addition of high flow cylinder heads, intake or camshaft. The cam timing may have an adverse effect on idle quality due to overlap of the intake and exhaust opening and closing.

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables. Changes in RPM causes the airflow to increase or decease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

The fact that the voltage is high suggests that there is a disturbance in the flow of air through the MAF. I don't recall your having said what kind of air intake system you have. That may be crucial to solving your problem if the MAF is the source of your troubles.

Tests to isolate your problem
1.) To isolate the MAF, disconnect it and start the car.
2.) See if the idle surge is still present: if so, disconnect the IAC.
3.) If the idle surge is still present, then disconnect the SPOUT and the IAC. The base idle should be a steady 625-650 RPM. If the surge is still present, or the engine is out of this RPM range, you have either a bad injector(s) or a mechanical problem.

The homemade CAI could very well be the source of the problem. The MAF needs to be a minimum of 4" from any bends. More distance from a bend may improve the airflow characteristics. The stock airbox flows better than most CAI kits, so if you still have it, put it back on the car.