Code 22 - MAP/Barometric Pressure Sensor
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yes this would cause a no start condition. Since the map sensor is comparing the pressure outside the intake to the pressure inside the intake and adjusting air and fuel from that. Then if you are not getting a reading then it doesn't know what the pressure is and can't set your fuel trim. So it gets confused and doesn't know what to do and either puts too much fuel or not enough in causing the car to stall.
If it's MAF, you would want the BAP (in this case) vented (not connected to manifold vac). Yours isnt connected to manifold vac by chance, is it?
I havent had a bad BAP sensor, but in theory it seems like it could screw with the stoichiometry enough to make a difference. I would test the wiring and sensor before replacing it (they are fairly cheap). Someone like Jrichker can offer a lot better advice.
Good luck.
I havent had a bad BAP sensor, but in theory it seems like it could screw with the stoichiometry enough to make a difference. I would test the wiring and sensor before replacing it (they are fairly cheap). Someone like Jrichker can offer a lot better advice.
Good luck.
MAP and BAP are basically the same sensor. The Mass Air cars vent the sensor to the outside atmosphere, while the Speed Density connect it to manifold vacuum. An important step in a Mass Air conversion is to disconnect the vaccum line from the MAP sesnor and cap or plug the manifold end to prevent a vaccum leak.
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 cable. 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.
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 cable. 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.
Marlboro_Man said:While everything you said is true to what i know.....My car was converted to MAF and it uses a map sensor (vacuum line connected) to run right?
If it's been converted to mass air then there should be NO vac line connected to the MAP sensor. As suggested by Hissin, it should be left unplugged and open to ambient air.
stang&2Birds
Founding Member
Marlboro_Man said:
Please re-read was has been posted. You do not cap off that connection on the MAP. You leave it open with nothing at all connected to it so that the port. That way, that port is open to the atmosphere and the EEC will be able to read the current atmospheric/barometric pressure.
For SD, the EEC reads the pressure from the MAP before the engine starts to know the barometric pressure at start up (before startup, the intake is at atmospheric pressure). In "just about all" cases, that's "good enough". Of course, don't drive up or down any mountains.
Yea, that method the the SD EEC uses to save a sensor isn't a very good method for people that go skiing or hiking. Still, it "works okay".I think you misunderstood me becuase i didn't explain myself very well.stang&2Birds said:Please re-read was has been posted. You do not cap off that connection on the MAP. You leave it open with nothing at all connected to it so that the port. That way, that port is open to the atmosphere and the EEC will be able to read the current atmospheric/barometric pressure.
For SD, the EEC reads the pressure from the MAP before the engine starts to know the barometric pressure at start up (before startup, the intake is at atmospheric pressure). In "just about all" cases, that's "good enough". Of course, don't drive up or down any mountains.
What i meant was that i would unplug the vacuum line that is currently connected to the map/bap sensor and then use a srew or something to plug up the vacuum line from the tree, that way there won't be a vacuum leak. Thus leaving the map/bap sensor open to atmosphere.
I'm fixing to go try it right now, be right back.
stang&2Birds
Founding Member
_jb_
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