The type of Volvo oxygen sensors you place in your car depends on when that car was built. A lot of older Volvos that use carburetors require less frequent "switching" of their sensors, as they demand more time to adjust from lean to rich air-fuel mixtures. Newer cars that use fuel-injection don't have this problem.

With fuel-injection, engines can more easily maintain an ideal 14.7:1 air-fuel ratio. Each cylinder has its own injector right by the intake port, making it simple to adjust air flow as your fuel mix shuttles between rich and lean. It also means that more responsive oxygen sensors are needed in the exhaust manifold so that the intake information reaches your onboard computer more efficiently.

Switching Systems for Volvo Oxygen Sensors

The calibration of your Volvo's oxygen sensors directly impacts how much fuel and air are combined in the cylinder. With throttle-body injection, the precursor to multi-point injection, switching occurs two to three times each second. As a reminder, this merely means that the voltage supplied by your Volvo's oxygen sensors cross the .45-volt threshold two to three times per second.

Nowadays, it's hard to find cars that even use throttle-body fuel injection. Multi-point systems are far more effective at increasing or reducing air-to-fuel ratios, so switching takes place even more rapidly. At an RPM level of about 2,500, the same car that switched two or three times per second with a throttle-body mechanism can switch as much as five to seven times each second with a multi-point setup.