MAF sensor - JeepForum.com

 
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post #1 of 8 Old 01-04-2008, 05:19 AM Thread Starter
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MAF sensor

For the 3.8 V6 what kind of Mass Air Flow sensor does it use?
Is it the same heated wire type as used by GM and BMW or is it different?
If different can you explain how the ECU makes it's proper fuel/air ratio mixtures on it's various maps.

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post #2 of 8 Old 01-04-2008, 06:21 AM
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Pretty sure it's mapped through MyGig

That damn thing does pretty much everything else!
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post #3 of 8 Old 01-04-2008, 12:02 PM
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The Jeep uses a MAP (Manifold Air Pressure) sensor, not a MAF, so it's measuring pressure, not air flow. The ECU does all the calculations to determine density and air-flow based on the manifold pressure and IAT (Intake Air Temperature) sensor values resulting in the fuel requirments at any given time.

From what I understand, MAP sensors are cheaper.

The MAP sensor is on the upper rear of the intake manifold. The little rectangular sensor.
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post #4 of 8 Old 01-04-2008, 12:32 PM Thread Starter
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^^^ thanks,
Was hoping it was a MAF, as I'm not familiar with the pressure system, geuss I'll have to do some research.
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post #5 of 8 Old 01-04-2008, 12:52 PM
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a MAP sensor is a fancy Vacuum sensor.. basicilly the more the engine is under load the closer to 0 your vacuum will be.. so they use the MAP sensor to determine how hard the engine is loaded.. 1/2 open throttle at real low RPM say shifting to too high of a ear for your speed will yield close to 0 vacuum and "full load" of engine indicated.. where as full throttle at super high RPM may read less than full engine load.. I prefer MAF to MAP because it doesnt completely screw up when you add a turbo or supercharger..
I guess I figured by now jeep would be using MAF.. MAP was used in the early 80's cars...
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post #6 of 8 Old 01-04-2008, 02:06 PM
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Chrysler engines use a combination of manifold air pressure (MAP), throttle position (TPS), and RPMs (plus upstream exhaust O2 sensor) as inputs. It's not as simple as one or the other. All these determine fuel injection pulse width and timing.

I don't know if any of the engines has variable valve timing as an "output".

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post #7 of 8 Old 01-04-2008, 03:04 PM Thread Starter
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Liquids, FYI MAF setups need a TPS and O2 sensors as well to make proper mixtures per given RPM.

Jeeparo hit the nail on the head for what my real plan is with this thread.
Turbo or Supercharging the JK.

I supercharged my BMW by simply bolting on a roots M62 SC after the MAF and the compute auto adjusts mapping for me all the way up to 10 PSI of boost (with a rising rate fuel pressure regulator).

Was hoping the JK would be just as easy. So now I have to figure out how to make positive pressure "BOOST" in the intake look like vacume and have the ECU able to map accuratly...

thanks again all for the info , looks like I have my work cut out for me.
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post #8 of 8 Old 01-04-2008, 03:27 PM
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You might take a look at some of the little black boxes made by Split Second. They have been one of the leaders in developing electronics to "fool" the ecu. I used their products successfully (albeit with a lot of tuning) in a different MAP-based car when I added a supercharger.

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