MAP sensor questions

[shrbrt]

do the numbers on the MAP sensors make a difference. I had a code 22, got a map from a junkyard and it cleared. the numbers are different so I was just wondering if anything will be changed

 

[Fett]

They are different between mass air and speed density.

 

[jrichker]

Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the atmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it. There is no way you can use a common cheap voltmeter or DVM to accurately measure the output signal.

The MAP/BARO sensor is mounted on the firewall behind the upper manifold.

Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce the jitter in the meter's readout.

If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer

Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cablet. It should be less than 1.5 ohm.

The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.

 

[795.0pacecar]

They are different between mass air and speed density.

They are the same.

They both send out the same fequencys at the same vacuum.

 

[petrabrule]

The radio frequency products can be called vehicle inspection which have a good function of detecting metals and even some potential danger signals. They can bring much safety and convenience to people's life. We have to admit that the advanced technology always gives us surprise and joy.

 

[jrichker]

The radio frequency products can be called vehicle inspection which have a good function of detecting metals and even some potential danger signals. They can bring much safety and convenience to people's life. We have to admit that the advanced technology always gives us surprise and joy.

Totally unrelated to the problem at hand. The MAP/Baro sensor operates an ultra low frequency, 153-80 HZ. It is not capable of producing RF energy that would disturb anything.

 

[84Ttop]

Totally unrelated to the problem at hand. The MAP/Baro sensor operates an ultra low frequency, 153-80 HZ. It is not capable of producing RF energy that would disturb anything.

I'm guessing this is a troll @Noobz347

 

[mikestang63]

On SD cars the sensor is a MAP sensor- the vacuum line from the port on the sensor is connected to the manifold. On a MAF car the port on the sensor is open and and reads the open air pressure - hence it's a BAP. It's the same sensor. All you need to do when converting from SD to MAF is unhook the vacuum line.