2002 Honda CR-V O2 sensor question

[Fsatsil]

Lately my 02 CRV has been getting poor gas mileage and I did all the usual fixes such as fuel injector cleaner, new air filter, new spark plugs, check tire pressure, check for frozen brake caliper.....etc but the poor mileage continues. The car idles smoothly and has plenty of power it's just getting bad gas mileage. So I plugged in my scan tool and there are no trouble codes and everything looks normal except for the upstream oxygen sensor. Most upstream O2 sensors I've seen switch rapidly from about .1v(lean) to .9v(rich) but my O2 sensor is staying at around .620v-.670v at idle as well as at 2k rpm. The car has 103k miles on it and the O2 sensor is the original so it could be going bad but I would think it would show a code if this was the case? I don't want to spend $100 for a new sensor if I'm not at least somewhat sure that it's bad. Any ideas?
Thanks

 

[SatinSilver]

Fwd model? I'd change the pcv valve which really wouldn't affect mileage too much but often overlooked. Alignment could be another thing to look at. Also an atf drain/fill is good preventative maintenance. Also maybe a sticking caliper.

 

[beast3300]

I'm pretty sure the front O2 is a wideband. It doesn't show a Sin wave pattern like narrow band. If you look up the price of the replacement you will see a large price difference between the front and rear sensor. The rear is a typical 4 wire as the front should be 5 wire.

Replacing the front O2 can increase fuel economy from an age and wear standpoint.

 

[Kool1]

I have an 03 CRV and have replaced the catalytic converter numerous times with aftermarket ones and then finally an OEM Honda one which cost me $1,200.00. The first one I replaced because a catalytic code came on at about 100,000 miles. I can tell you that as soon as I replaced my first cat, my mileage increased. I did not feel a power increase but did find a mileage increase. Hopefully your cat is not ready to give out; maybe you can install a test pipe in place of your current cat to see if your mileage jumps up. Good luck and keep us informed on your findings.

 

[Fsatsil]

Originally Posted By: SatinSilver
Fwd model? I'd change the pcv valve which really wouldn't affect mileage too much but often overlooked. Alignment could be another thing to look at. Also an atf drain/fill is good preventative maintenance. Also maybe a sticking caliper.

It's an AWD model and I just recently had new tires and an alignment done. I also did a full 4x ATF drain/fill, PSF drain/fill, rear diff drain/fill, oil change, and checked the brakes this month. The PCV valve is next on my list of things to do and I purchased the valve but I haven't had a change to put it in. I would think if the PCV valve was bad the car would be using oil but I've never had to add even a drop during a 5k OCI.


Originally Posted By: beast3300
I'm pretty sure the front O2 is a wideband. It doesn't show a Sin wave pattern like narrow band. If you look up the price of the replacement you will see a large price difference between the front and rear sensor. The rear is a typical 4 wire as the front should be 5 wire.

Replacing the front O2 can increase fuel economy from an age and wear standpoint.

The upstream and downstream O2 sensors on the gen2 CRV are both the 4wire types and they run around $100 and $80 for Denso replacements. I'm keeping my fingers crossed that it's a bad O2 sensor and not the cat converter.

Thanks for the help guys I'm going to take a look in the service manual and see if I can find any more info on the O2 sensor voltage. Enjoy your Halloween

 

[Fsatsil]

Originally Posted By: Kool1
I have an 03 CRV and have replaced the catalytic converter numerous times with aftermarket ones and then finally an OEM Honda one which cost me $1,200.00. The first one I replaced because a catalytic code came on at about 100,000 miles. I can tell you that as soon as I replaced my first cat, my mileage increased. I did not feel a power increase but did find a mileage increase. Hopefully your cat is not ready to give out; maybe you can install a test pipe in place of your current cat to see if your mileage jumps up. Good luck and keep us informed on your findings.

Do you by any chance have a scan tool?

 

[Kool1]

Nope, I don't have a scan tool. I only have a code reader.

 

[Fsatsil]

I did a bit more research and testing using the Honda service manual and some online resources and it looks like it's normal for the upstream sensor voltage to stay around .6v. I did some tests to induce a lean and rich reading and the sensor responded correctly. I think I'm going to run another bottle of Techron through the gas and try a different gas station for the next few tanks to see if there is any difference. Thanks for the help guys.

 

[vortex9]

How much has you fuel mileage been affected percentage wise? The CRV will definetly give you a CEL when the upstream 02 sensor needs changing. As it did on my 03. In my case there was no noticeable fuel economy difference before and after I changed out the 02 sensor.