QuestionI recently had my 1989 chevy blazer looked at and they said the computer said o2 error so I replace the o2 sensor by the exhaust manifold. Is There another one because my check engine light is still on.
Thank you
Michael
AnswerHello Michael,
First...don't take your truck back there.....I will explain.An Oxygen sensor measures the percentage of oxygen in the exhaust stream, and depending on what it measures, it will tell the ECM,(computer), that the mixture passing through the engine unburned is either too rich, or too lean, but not why.
Some of the reasons the exhaust might be too rich are, a bad spark plug, bad plug wires, dirty air filter, ets.
Some lean readings could be a vacuum leak, dirty fuel filter, low fuel pressure, dirty injectors, etc.
The point I am trying to make is, if the oxygen sensor code appears, it could be that a perfectly normal oxygen sensor is doing exactly what it should...tell you there is a problem.
problem is, though, that the oxygen sensor isn't the problem...it is the thing that is working correctly.
Now,,, if your shop doesn't understand that, then I wouldn't want them trying to guess at what expensive component I should pay for next.
You need to find out what code the sensor is setting, then work from there.
And all the sensors can be tested individually, before just replacing something on a GUESS.
A tuneup may be what you need, but without more information, such as maintenance history, miles, and some other variables, even that is a guess.
Good luck,
Van
