what is a MAP sensor?

[cruisergt]

Check engine light came on, Car rides very bad. Dealer said they have to replace map sensor and PCM.

[IRPT]

Refers to a manifold absolute pressure sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere. This information is used by the engine computer to monitor engine load (vacuum drops when the engine is under load or at wide open throttle). When the engine is under load, the computer may alter spark timing and the fuel mixture to improve performance and emissions.

[MX-5]

There is a section at www.ptdiy.net that describes all the PT components. The MAP and about 100 others are covered.

[Big Al]

quote:Originally posted by IRPT

Refers to a manifold absolute pressure sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere. This information is used by the engine computer to monitor engine load (vacuum drops when the engine is under load or at wide open throttle). When the engine is under load, the computer may alter spark timing and the fuel mixture to improve performance and emissions.

Actually - this is "absolute" pressure, which is not in relationship to the outside atmosphere. That would be relative pressure, which is what a boost gauge measures.

[IRPT]

quote:Originally posted by Big Al

Actually - this is "absolute" pressure, which is not in relationship to the outside atmosphere. That would be relative pressure, which is what a boost gauge measures.

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From PTDIY:
The MAP serves as a PCM input, using a silicon based sensing unit, to provide data on the manifold vacuum that draws the air/fuel mixture into the combustion chamber. The PCM requires this information to determine injector pulse width and spark advance. When MAP equals Barometric pressure, the pulse width will be at maximum.

The MAP sensor input is the number one contributor to pulse width. The most important function of the MAP sensor is to determine barometric pressure.

Read full article here:http://www.ptdoityourself.net/ptmapsensorguide.html
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Barometric pressure = outside atmosphere

[Turbo Tommy]

If the 2.4 turbo programing is anything like older chryser turbos, which for their time had excellent logic programs, and addaptive logic, the map sensor read 3 things. Vaccum in the intake manifold, boost pressure in the intake manifold, and outside barometric pressure. If you have read about the logic programing in this motor it will vary boost acording to barametric pressure outside the motor, ie elevation, to suply more boost as elevation increases, in order to have the same output at high elevation as sea level, since air is thinner at high altitude, and denser at ow altitiude. The denser the air the more power.

Of course the sensor has a range it can read from, usually, infinite vacuum to 18-20 psi, give or take. So if you upgrade to a logic module with higher boost, the sensor must be changed to on that can read to a higher level.

[romli]

quote:Originally posted by IRPT
When MAP equals Barometric pressure, the pulse width will be at maximum.

Not with a turbo!

[cruisergt]

Now I have another Question. Do you think Chrysler would have paid for replacement of the map sensor under warranty if I had the Stage 1 installed.

[RD CHILI]

Cruisergt

Exactly what is your car doing? Is it surging at idle and decelleration? Please refer to my posts on this forum. The dealer has replaced my map sensor several times and the PCM. It's back in the shop again for the 5th time same problem. I'm in talks with DC now to replace the vehicle (04 GT Inferno Red). Also there is recall # C30, I noted it in my other posts as well, read it and have your dealer check the PCM / harness connectors. This surging condition almost got me into a bad accident when it stalled on me as pulled into traffic. Good luck!
[xx(]

[Turbo Tommy]

pull your codes, use your check engine light. get your key, put it in the ignition, turn it to on (lights on dash come on) then off, then on, then off, then on, and leave it on, never crank the motor.

So to simplify On-Off-On-Off-On

Then read the numbers that come up in the odometer display. It should start with a P and have 5 charecters total.

Let us know what they are. if you couldn't get them all fast enough, do it again. If you have no codes, it will say "done"

If your light is on anyway, you have set some code(s) and are into a limp in mode most likely.