where baro sensor 83 el camino

[saucee115]

I HAVE AN 83 EL CAMINO SS. IT IS COMPUTER CONTROLLED AND HAS THE STOCK 305CI MINUS A FEW PARTS. MY ECM CODE SAYS THAT THE BAROMETRIC PRESSURE CIRCUIT IS LOW. i WANT TO REPLACE IT BUT CANT FIND IT. PEOPLE HAVE TOLD ME THAT IT HAS A VACCUM LINE THAT LEADS TO THE CARB, FOLLOWED THEM ALL AND EVEN HAVE THE CHEVY MAUNAL AND STILL CANT FIND IT. CAN ANYONE HELP OR HAVE A PIC SO I CAN SEE WHAT IT LOOKS LIKE IT. SHOULD BE NEAR THE PASSENGER INNER FENDER I REPLACED THE MAP SENSOR BUT THAT WASNT IT. tHANKS

 

[megaladon6]

the baro is a black rectangle mounted on the pass side fender/wheel well to the rear of the overflow bottle. first i'd just replace the vacuum line and check the connector for corrosion and tightness.

 

[saucee115]

baro sensor

thanks i will change all vaccum lines couldnt hurt but that rectangle box near the overflow on my 83 el camino is a map sensor which i replaced, im wondering if either im missing the baro sensor or if the map sensor was the baro sensor of that year. i understand what they both, do the map and baro sensor. but thanks for your help.

 

[megaladon6]

whoops. the baro can also be under the drivers side dash.

 

[saucee115]

thanks for the info but the part that i replaced was the map sensor. today i went to a gm dealership to look at the part and the baro sensor and map sensor are the same part # meaning its the same thing. ill just check the wiring and check the resistance. my wiring seems old and brittle. Ill replace the vaccum lines also but thanks again for the help.

 

[Mikes455Wagon]

All a map sensor is is a barometric pressure sensor. They come in several forms such as 1 bar, 2 bar, 3 bar etc. I have got to play with them alot and tricking them in some turbo applications I have done. 1 bar is 14.7 or atmospheric pressure, 2 bar is 29.4 or atmospheric pressure plus 14.7 psi and so on, you get the idea. Given your showing a low circuit voltage I would check the supply voltage going to the sensor and see if its 5 volt. I believe it should be but can't check my shop manual, its at home and I am off at school..sorry

 

[megaladon6]

a baro sensor measures barometric or atmospheric pressure it will never read more than 32inHg (1bar). a MAP measures the absolute pressure in the intake manifold, it will only be a 2bar or higher on forced induction. they are two different signals. very rarely a system will use a differential pressure sensor that has both sensors together. you mostly see them on EGR systems.
to check the ckt: test for +5v between the gray+ and black(-) wires, with the sensor plugged in-backprobe the green and black wires for signal. you will want to connect a vacuum pump and verify that the signal changes with vacuum.
it should be between 2.5 and 4.5v with the engine running