Is this the MAP sensor?

[MoclovFlop]

I have a 2000 legacy GT and saw some little circular plug at the front of my airbox directly right of the left mounting point for the airbox. I was curious if this is the MAP sensor, and if not, what is it?

Here's a pic of what i mean ...NOT MY PICTURE please click thumbnail
http://img506.imageshack.us/img506/656/newpicturemr8.th.png (http://img506.imageshack.us/my.php?image=newpicturemr8.png)

[jmgtp]

I believe what you have circled is the IAT (intake air temperature) sensor - which does simply as the name implies and lets the ecm know the temperature of the air charge, which it uses in it's calculation of how much fuel to deliver, after all different air temps mean varying air density.

The MAP sensor should be either bolted directly to the intake manifold OR on a vacuum line off the intake manifold. It should be connected to the manifold (or a vacuum line off the manifold) somplace between the throttle body and cylinder head. It's raining right now or I would check on my own car, but it is very likely on the plenum part of the intake manifold (or connected to a vacuum line off the plenum). The key thing to remember is that it will not be before the throttlebody.

Not to get too wordy but here is why:

The MAP (manifold absolute pressure) sensor on our normally aspirated engines reads manifold vacuum (no boost here!). When the throttlebody is closed there exist vacuum within the intake manifold due to the pistons trying to 'suck' more air than the throttlebody allows - the opposite is true at full throttle where there will be almost no vacuum at all since the pistons may draw as much air as they please limited only by the efficiency of the heads/manifolds/intake. If the sensor were outside of the throttlebody it would not sense the vacuum within the manifold. Also, *most* (read: I can't verify this on the 2.5 since I've never had the need to know where it is) MAP sensors are 3 wires (ground, 5v reference, and signal) so that may be something to look for in your search.

edit: is 2000 a MAF year? If so you likely don't have a MAP sensor.... If your intake system (the series of plastic tubes and the air filter box) look exactly the same as the one pictured then you do indeed have MAP.

good luck!

[Wiscon_Mark]

2000 is MAP sensor. It's right above the throttle body.

[jmgtp]

The Haynes manual indicates that on auto tranny cars a map/iat combo sensor is used and is located on the intake manifold near the coilpack. My manual tranny 01 GT is pictured below, where the MAP sensor is located on the top of the throttlebody as suggested by Wiscon_Mark (click for bigger image).

Do you suspect your MAP sensor to be faulty?

-John

http://img76.imageshack.us/img76/6980/mapsensornk9.th.jpg (http://img76.imageshack.us/my.php?image=mapsensornk9.jpg)

[MoclovFlop]

No, I don't think anything is wrong with my MAP, I was just curious because if i do some sort of intake, no systems seem to have a place to put that sensor I pointed out (air temp sensor). So I was just curious. What have other people done with that air temp sonsor when you put on an aftermarket intake?

[Wiscon_Mark]

I have an intake that has the place for the MAP sensor...but not place for the MAF sensor :roll:

It was advertised to 2nd gen Legacys too... :x

[MoclovFlop]

I know there are intakes with places for the sensors, but what would I do with the air temp sensor that I pointed out? drill a hole in the inkate tube?

[rougeben83]

The car in the pic is a manual Legacy...I know because it's mine.

[MoclovFlop]

Hope it's ok I used your picture, anyone know what i should do?

[rougeben83]

Hope it's ok I used your picture, anyone know what i should do?
Nah, it's fine :P

So you have an auto then? As for the IAT, yeah just drill a hole into the intake tube the same size as therubber grommet that the IAT is squezed into on the box, transfer grommet to new intake and insert IAT there.

As long as it's relatively close to the TB it should read about the same temp as if it was on the box.

[MoclovFlop]

Nope, it's a manual, did they only come with auto trannys? hope not, otherwise i have a frankinstein thing going on. And thanks for the advise, I was thinking the same thing (drill a hole), so i'll just deal with it when the time comes.

[rougeben83]

if it's a manual then that thing on the box is just the IAT. The real MAF is at the TB. no biggie.

also remember to plug in the two egr tubes (I think those are what they are) that stick on the side of the box.

[jmgtp]

also remember to plug in the two egr tubes (I think those are what they are) that stick on the side of the box.

Those tubes are part of the pcv system. They simply allow filtered air to be drawn through the valve covers.

[rougeben83]

also remember to plug in the two egr tubes (I think those are what they are) that stick on the side of the box.

Those tubes are part of the pcv system. They simply allow filtered air to be drawn through the valve covers.

Wait, i thought the PCV is the one in the middle of the block with the valve and a tube that runs to the intake manifold?

[Wiscon_Mark]

He means the EGR system.