[Samger2]

2004 CRV EX, CEL came on, which pointed back to the pre cat 02. Replaced it with the Denso 234-9005 which after research, appears to be the Denso replacement for the factory sensor.

I drive about 32 miles per day, 20 of those miles are freeway miles. Prior to the CEL and sensor replacement, gas light would come on usually around 280 miles....I could push it to about 300 miles maybe a little more on a tank before filling up.

Ever since the replacement of the sensor it's dropped pretty drastically. The last two fillups have resulted in 19.78 mpg, followed by 18.55 mpg. This last time my gas light came on at 218 miles...which seems very low for this vehicle.

I tried doing a battery reset, so this tank will tell the results of that.

I do realize that we're in the winter gas blend season, but I can't imagine it would effect things this drastically.

Any thoughts? Could it be a bad sensor? If so I'd think the CEL would come back on.

Could it be the difference between the OEM sensor and the Denso equivalent? If so, why would that be if I bought the Denso replacement with the same Denso part number?

Any thoughts are greatly appreciated.

 

[Tigris99]

Actually a 5% loss considering weather changes and so on really isnt bad. Neither is 18.5mpg in the winter for city driving. I've tweaked my 2003 alot and I'm happy at 18 with my bigger tires.

wind, poor road conditions, winter blend fuel (also could have gotten gas that had some moisture in it) all can drop things drastically.

Keep driving it for a while, including put a bottle of injector cleaner or seafoam in when your at about 1/4 tank left.

Should see some improvement.

It does take about 1-2 tanks of fuel for a new sensor to break in.

 

[Samger2]

Thanks for the reply. I'll keep an eye on it and hopefully it improves over time.

 

[BDub]

Denso is the OE manufacturer. Anytime you make changes dealing with the air/fuel ratio, you need to disconnect the battery to clear the learned values from the PCM. Most likely what was happening is that it was running on a fuel map that was adjusted to compensate for the failing sensor. Which was most likely running it on the rich side.

 

[Samger2]

Denso is the OE manufacturer. Anytime you make changes dealing with the air/fuel ratio, you need to disconnect the battery to clear the learned values from the PCM. Most likely what was happening is that it was running on a fuel map that was adjusted to compensate for the failing sensor. Which was most likely running it on the rich side.

Thanks for the reply. I did do this, but not until this last fillup...so I'll monitor from here on out.

 

[Samger2]

So after I did the battery reset the MPG went up to 21.72. I also started hearing an awful grinding noise so I pulled the wheels and found that the R/R caliper was seized and my pads were smoked. The pads were just replaced 6k miles ago, and already trashed, so I'm sure that caliper binding had something to do with the lower MPG as well.

I replaced the pads rotors and calipers on Wednesday, so I'm curious to see if the MPG increases a bit more.