hi, ive been having some bog issues with my crx driving down the highway, and would like to diagnose the problem. every now and then i feel the car starting to bog down and need to apply more throttle to maintain speed. i found a simple fix of shutting off the car and then turning it back on. then it doesnt happen for a while again. As far as i know the 02 sensor is unplugged and that is why an engine check light comes on every now and then too.. wondering if that is the problem.

also, when my car is warm it sometimes cant decide where to idle. it fluxuates from 2000 to 1000 rpm. i was wondering if this is related to the first problem.

 

Hook your O2 sensor back up and see how it runs. That's where I would start...

 

i really have no clue what the 02 sensor is, the guy i bought it from told me that it was unplugged when i bought it.

 

http://en.wikipedia.org/wiki/O2_sensor

Automotive oxygen sensors, colloquially known as O2 sensors, make modern electronic fuel injection and emission control possible. They determine if the air fuel ratio exiting a gas-combustion engine is rich (with unburnt fuel vapor) or lean (with excess oxygen). Closed-loop feedback-controlled fuel injection varies the fuel injector output according to real-time sensor data rather than operating with a predetermined (open-loop) fuel map. In addition to improving overall engine operation, they reduce the amounts of both unburnt fuel and oxides of nitrogen from entering the atmosphere. Unburnt fuel is pollution in the form of air-borne hydrocarbons, while oxides of nitrogen (NOx gases) are a result of excess air in the fuel mixture and cause smog and acid rain. Volvo was the first automobile manufacturer to employ this technology in the late 70s, along with the 3-way catalyst.

Information on oxygen concentration is sent to the engine management computer or ECU, which adjusts the mixture to give the engine the best possible fuel economy and lowest possible exhaust emissions. Failure of these sensors, either through normal aging, the use of leaded fuels, or fuel contamination with silicones or silicates, for example, can lead to damage of an automobile's catalytic converter and expensive repairs.

Tampering with or modifying the signal that the oxygen sensor sends to the engine computer can be detrimental to emissions control and can even damage the engine. When the engine is under low-load conditions (such as when accelerating very gently, or maintaining a constant speed), it is operating in 'closed-loop mode'. This refers to a feedback loop between the fuel injectors and the oxygen sensor, to maintain stoichiometric ratio. If modifications cause the mixture to run lean, there will be a slight increase in fuel economy, but a great increase in nitrogen oxide emissions, and the risk of damaging the engine due to detonation and excessively high exhaust gas temperatures. If modifications cause the mixture to run rich, then there will be a slight increase in power, again at the risk of overheating and igniting the catalytic converter, while decreasing fuel economy and increasing hydrocarbon emissions.

When an internal combustion engine is under high load (such as when using wide-open throttle), the output of the oxygen sensor is ignored, and the engine automatically enriches the mixture to protect the engine. Any changes in the sensor output will be ignored in this state, as are changes from the air flow meter, which might otherwise lower engine performance due to the mixture being too rich or too lean, and increase the risk of engine damage due to detonation if the mixture is too lean.

-Taken from Wikipedia.

 

Well one sure way to see where your O2 is, is to just follow your exhaust from your Exhaust Manifold (header) until you see a little sensor sticking out of the exhaust or header. It will have a single wire going to it. Once you find that trace the single wire up until you find where it is unplugged at.

 

alright sweet. so it is mounted in the exhaust manifold. and without the 02 sensor my car is probably running rich. would plugging that in fix my idle problem too? thanks

 

It could quite possibly fix your problems. Let us know how it works out.

 

k im going to check it out.