B

Backfire Suppressor Valve:

BACKFIRE SUPPRESSOR VALVE (BSV) - A device used in conjunction with the early design "Thermactor" exhaust emission system. Its primary function is to lean-out the excessively rich fuel mixture which follows closing of the throttle after acceleration. Allows additional air into the induction system whenever intake manifold vacuum increases.

Backpressure Variable Transducer System:

BACKPRESSURE VARIABLE TRANSDUCER (BVT) SYSTEM - A system combining a ported EGR valve and a backpressure variable transducer to control emissions of NO(x). The BVT system is used on most 1.6L and 2.3L passenger car applications.
BAFFLE or BAFFLE PLATE - An obstruction for reducing or deflecting flow of gases or sound.

Barometric and Manifold Absolute Pressure Sensor:

BAROMETRIC AND MANIFOLD ABSOLUTE PRESSURE SENSOR (BMAP) - Sensor housing containing both MAP and BP sensors. The barometric pressure sensor monitors atmospheric pressure and allows adjustment of spark advance, EGR flows, and air/fuel ratio as a function of altitude. The manifold absolute pressure sensor monitors engine vacuum and provides engine load information which is used to calculate spark advance, EGR flow in air/fuel
ratio. See EGR Valve (Integral Backpressure Transducer) and Manifold Absolute Pressure Sensor. Replaced by SCAP Sensor in EEC IV Systems.
BAROMETRIC PRESSURE (BP) - A sensor or its signal circuit that sends a varying frequency signal to the processor relating actual barometric pressure.

BIMETAL HEAT SENSOR (BHS) - A strip (often coiled) made up of two metals that have different expansion characteristics. These strips are used in thermostatically controlled devices because they will move or bend toward the metal that expands least when heat is applied.


BOOST SOLENOID (SBS) - The ECA uses this solenoid to control boost pressure to the turbocharger wastegate. This is a normally closed solenoid that, when energized by the ECA, allows boost pressure from the turbocharger compressor outlet to bleed through the solenoid back into the turbocharger compressor.

BOWL VENT PORT (BV) - Port in a carburetor which vents fumes and excess pressure from the bowl to maintain atmospheric pressure.


BREAKOUT BOX (BOB) - An EEC-IV test device which connects in series with the processor and the processor harness and permits measurements of inputs into and outputs from the ECA.
BYPASS VALVE (BPV) - (1) Valve that opens under certain conditions to permit a flow of liquid or gas by some alternate to its normal route. These are bypass valves in oil filters, air systems and power steering pumps. (2) A vacuum controlled valve in the Thermactor system which allows air from the air pump to be injected into the exhaust system or bypassed to atmosphere when not required. It also provides a pressure relief function to protect the air pump from high pressures. These valves may be mounted on the air pump (pump mounted) or mounted in the thermactor hose line (remote mounted). The two basic types are: normally closed (bypasses air with no vacuum signal applied), and normally open (allows air to flow through the valve to the exhaust system with no vacuum signal applied).