Mileage Rollercoaster 32 To 56 Mpg
Hey Everyone,
I have a strange fluctuation in my Civic VX's tank to tank mpg. (32 to 56 MPG) The gaslog tells the story My O2 sensor has about 130,000 miles on it and sometimes the check engine light comes on and I turn the car off and on again to get the light off. I guess one question would be can an O2 sensor ?come and go? like that? I mean, run great (deliver +50 mpg) and then ?foul out?. Thoughts on other causes? |
I would think either the sensor is good, or its not. Are you sure the computer is throwing an O2 sensor code? I'd probably look into a sticking EGR valve, or some other mechanical part. I know I had a similar problem on my Buick years ago and the vapor cannister purge valve was sticking. I don't know if Honda used vapor canisters or purge valves on that year/model car though.
-Jay |
Definitely pull the codes and see what your CEL is on about.
|
Are you sure it is actually a mpg issue. If you fill up at different gas stations with unlevel parking pads and pump cuttoff switches with different sensitivities you might just not be getting the tank completly filled every time.
|
Probably the gas pump. I filled today from the uphil side of the pump and I was about 1 gal short of what my trip computer said it should take and it wouldn't take another drop. I'm usually +/- .5% if I use the same pump as compared to the readout
|
My VX stated doing the same. Then it eventually just got bad MPG. The cel would turn on every once and a while like yours. It showed a code 48 for the O2 or laf sensor. I ordered a new one from honda parts on the web.
Hope it works, $363 is a lot of money for a sensor. Local Honda dealer wanted 430. |
Quote:
I ordered a genuine 5-wire Bosch VX specific o2 sensor and it discovered it threw the CEL 48 and I got my worst mpg ever with that CEL issue. btw, the cel went away every time I turned the engine off, only to return within a couple of minutes. Also, on the only full tank I ran with that sensor before returning it, my gas mileage fell off a cliff to ~35mpg, see gas log. I just put in a new l1h1 this week and immediately got to ~44.8. I still think there is upside MPG potential to sort out. Below is a link to a place that is selling made in Japan apparent l1h1 oem replacement sensors for $99 shipped. (Having just returned the above Bosch, I was not real confident when I placed the order as it was not from Honda). I doubt these are going to be around very long at these prices: Got it here, scroll to the very bottom of page. It is truly plug and play, internal resistor, visually an identical to the oem. https://stores.channeladvisor.com/Aut...t=5&scat=20363 |
Quote:
:thumbup: |
Thanks everyone especially SCoupe,
Great info! I have taken the plunge and ordered an O2 sensor from the link above. $99.99 delivered. Unheard of price for the VX's 5 wire sensor. I will post my findings with the unit once I get it. I hope to keep the VX in lean burn mode were it should be with the new sensor. The theory about different gas pump shut off points accounting for a 30% variance in my gaslog is a little far fetched. Besides don't we use the amount used to compute our MPG? |
Quote:
|
All times are GMT -8. The time now is 10:08 AM. |
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.