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Old 01-08-2011, 04:58 AM
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Default Question concerning "map" & "maf" sensor

MAP Sensor and MAF Sensor... What's the difference?

Some vehicles have one or the other and some have both.

Does the 2.0 (AEG) Engine have a MAP Sensor (Manifold Absolute Pressure Sensor)??? If so, I've read that this works with the MAF (Mass Air Flow Sensor). How would one know if the MAP Sensor is faulty? Is it possible to give the MAF Sensor a false reading?
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Old 01-08-2011, 11:29 AM
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To my understanding the MAP is used on turbo applications, and the MAF is used in all applications. The MAP controls the boost made from the tubo. I don't believe the 2.0 has a MAP sensor.
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Old 01-08-2011, 01:05 PM
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Yup, there is only a MAF sensor on a 2.0 AEG.
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Old 01-08-2011, 02:16 PM
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O.K., Thanks Guys!
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Old 05-12-2011, 03:07 PM
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I just ran across this and I have to comment.
A MAP sensor in my opinion is a far more accurate way to determine the amount of air coming into the engine than a MAF is. Mass Air Flow Sensors can only determine the amount of air going by the sensor. If there's a leak in the intake or corresponding vacuum lines the MAF has no way to know about it to let the car compensate. Manifold Absolute Pressure sensors read the pressure in the intake, whether it be negative or positive pressure. By reading the position of the throttle plate (throttle position sensor) and the amount of pressure in the intake the ecu can better determine the conditions of the engine and it's load to determine a sufficient air fuel mixture. The ability to read positive pressure is what makes them necessary for turbo applications. A turbo forces air into the engine creating a positive pressure system in the intake (forced induction, boost). A MAF has no way of determining the positive pressure in the intake and would be useless for turbo applications. Older turbo cars that used a MAF basically started dumping fuel into the cylinders to compensate for boost, almost unregulated. Newer cars are much better at determining how much fuel is necessary by the amount of positive pressure in the intake. I wish there was some way to replace the MAF in these cars with a MAP all together (not combined). MAF sensors go bad or get dirty often, they're unreliable and frankly they're just old tech that should have been tossed out decades ago. MAP is the way of the future. With some after market ecus you can actually base your entire fuel table off the MAP sensor and in my experience, it's far more stable and accurate. The MegaSquirt ECU (diyautotune.com) changing the accel enrichment measurement from TPS to MAP has smoothed out every car I've used it on in all ranges of the fuel tables. Maybe one day we can find a way to trick the ECU in the NB into using a MAP sensor instead.
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Old 05-12-2011, 04:57 PM
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MAF is cheap and easy to tune, makes a hardpoint that is very hard to get around so manufacturers can easily limit potential performance.

MAP is harder to tune but will get you better power and efficiency. Incredibly flexible, can even put low boost turbo onto cars that never had turbo's and they'll work without touching the ECU.

Many Turbo cars use draw through MAF systems, but the MAF has no way of compensating for heat soak. Also alot of ricers love to bolt on blow off valves that vent to atmosphere, and this causes the ECU to freak out and go into dump fuel mode.

MAP is truly the superior system, it's far more rugged(no stupid sensor wire/sheet to get dirty or burn), far more capable, automatically compensates for altitude/temperature. It's just better, but don't tell the VW engineers, they want you to fight with that horrible antiquated MAF that needs an air strainer because turbulence makes it get real stupid real fast, that goes out every couple of years.
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Old 05-12-2011, 05:38 PM
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I wonder if anyone has looked into replacing the MAF with a MAP on the NB? Anyone know the sensor ranges for airflow and how they would correspond with a MAP?
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Old 05-12-2011, 06:37 PM
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Need to completely replace the ecu, to do that swap.
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Old 05-12-2011, 07:46 PM
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Probably. Are the newer beetles using a MAF still and if not at what year did they stop?
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Old 05-12-2011, 08:13 PM
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All VW's as far as I know are all MAF based.
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