Mechanic Types: Question about Honda Check Engine Light

[justint]

My 98 CR-V had a check engine light about a week ago and I pulled the code from the computer using the paper clip trick. The code was 67 for catalyst system efficiency. I reset it, and now it is back on the same code after about 500 miles of driving. The car seems to run and drive fine although my mileage is down from being in limp home mode.

Any opinions on whether it is really my catalytic convertor? I just passed the emissions test three weeks ago, and the engine seems to run fine. Maybe I have a bad rear 02 sensor? The dealer is just going to start replacing expensive sensors and such I assume, so I wanted some opinions first.

 

[HiTek21]

I doubt your catalytic convert, most likely your O2 Sensor is going bad. My mom had a bad O2 Sensor on her 98 Prelude. When her engine check light came on we just took it down to the dealership they plugged in that diagnostic multi meter into the ECU and it showed exactly what is wrong with it and they changed the O2 sensor that was going bad.

 

[Analog]

Originally posted by: justint
My 98 CR-V had a check engine light about a week ago and I pulled the code from the computer using the paper clip trick. The code was 67 for catalyst system efficiency. I reset it, and now it is back on the same code after about 500 miles of driving. The car seems to run and drive fine although my mileage is down from being in limp home mode.

Any opinions on whether it is really my catalytic convertor? I just passed the emissions test three weeks ago, and the engine seems to run fine. Maybe I have a bad rear 02 sensor? The dealer is just going to start replacing expensive sensors and such I assume, so I wanted some opinions first.

the O2 sensor can be easily checked with a volt meter. If you have one, try checking it out. There should be a good deal of info on the net about the voltage level etc.

 

[Vette73]

It can actually be a lot of things. All it is saying is that the gas in the exhust is not at the right mixture rate. Could be a bad O2 sensor, or a plug that is not firing 100%, etc....

How many miles are on it and have you been keeping up with oil changes, fuel filters, etc....???????


But don't start guessing and replace parts you might not need.

 

[squirrel dog]

If you fill the car with gas with the motor running it will also give you that code .

 

[Monel Funkawitz]

My Advice:

98.4% of the time, it is the O2 sensor. Catalytic converters are VERY hard to destroy, dispite what the parts companys tell you. They can take alot of abuse. Most cars have a O2 sensor on the manifold, that monitors O2 and controlls the engine in closed loop, and they have one after the catalytic that monitors catalytic efficiency. A bad manifold O2 will keep the engine from going into closed loop mode, and ignores 90% of the sensors, thus operating in limp home mode. A bad catalytic sensor will activate the CEL, but won't usually affect performance. O2 sensors operate in a hellish environment, and take a beating.

Be careful checking O2 sensors with a meter. Some ECU computers can be destroyed by this. What I would do is blast off the O2 with carburator cleaner and try it again. Sometimes this fixes it for a short period of time and will give you an idea if it is bad or not.

Most O2 sensors are VERY reasonable in price. With your car being a 98, I'd replace the O2 sensors anyway. They are good for around 50-70k miles before performance drops. For the cost of new sensors, you will save in gas.

 

[SuperSix]

Originally posted by: yellowfiero

Originally posted by: justint
My 98 CR-V had a check engine light about a week ago and I pulled the code from the computer using the paper clip trick. The code was 67 for catalyst system efficiency. I reset it, and now it is back on the same code after about 500 miles of driving. The car seems to run and drive fine although my mileage is down from being in limp home mode.

Any opinions on whether it is really my catalytic convertor? I just passed the emissions test three weeks ago, and the engine seems to run fine. Maybe I have a bad rear 02 sensor? The dealer is just going to start replacing expensive sensors and such I assume, so I wanted some opinions first.

the O2 sensor can be easily checked with a volt meter. If you have one, try checking it out. There should be a good deal of info on the net about the voltage level etc.

It's not that easy to check modrn o2 sensors with meters, you need an extremely sensitive meter, and it is never a correct way to check an o2.

I agree that the problem is more than likely a bad o2, and your car may have up to 4. *I* would replace all of them @ once, depending on the mileage on the car. If you don't want to do that, you will need to find someone to hook it up to an engine analyzer, (Honda dealer, etc) it may pinpoint which one is bad.