FYI: B230F oxygen sensor / gas mileage

[e777]

I just wanted to share my experience after having changed the oxygen sensor on my 90 740 wagon.

The wagon has been getting around 19mpg in the city and about the same on the freeway. All of the ignition components are new so I decided to replace the oxygen sensor to see if I could boost the mileage. I have not verified the mpg in the city, but after about 80 miles of freeway driving I recorded 27mpg, with 92 octane gas. Very pleased!

A word of caution: If you buy from IPD, then it appears they not have the NTK (an NGK brand) sensor that you need for Regina ignition. When I selected my vehicle on the IPD site, only the Bosch sensor came up, which is not the one you want for Regina. Eeuroparts does have the NTK sensor.

Anyway, I hope you have the same success boosting your mpg.

[billofdurham]

Thank you for this information.

It does show that not all problems with sensors will produce a code and a little thought can save you a lot of cash.

Bill.

[e777]

To follow up on my previous message...

This is very weird. I continue to get excellent mileage on the highway. But, a couple of weeks ago, when temperatures were mostly below 32 degrees Fahrenheit, I was driving the 740 and had a chance to gauge in-city fuel consumption. I was shocked to see I got 15MPG, worse than before I replaced the O-sensor!

Now, could this be because the temperatures were so cold and the car never had a good chance to warm up during my 4.5 mile commute to work?

I also noticed my oil smelled rather gassy when I changed it last week, which means my injectors might be malfunctioning and possibly affecting mileage(?).

Thanks for any thoughts you might have on this!

Eric
90 740 wagon 271K miles

[billofdurham]

When I had my 740, too many years ago now to be able to give dates, I too had a 4.5 mile commute in very heavy, stop/start traffic. This would normally take 30 - 45 minutes. In warm weather I would get about 19mpg, bearing in mind our gallons are bigger than yours. Winter with below freezing temps would see that plummet to 14mpg. The engine did reach working temp in the cold weather but it took a lot longer than in the warmer periods.

As for the smell, I noticed this on one or two occasions and had a chat with some of our mechanics. They told me to wait for the warmer weather and see if I had the same smell. Their consensus of opinion was that the fuel wasn't burning off as well as in warm weather with some mixing with the oil. Around came Spring, warmer temps, fuel consumption went back to 19mpg and the smell disappeared.

Bill.

[e777]

Thanks, Bill. I am glad to hear it is temp related and not something more serious.

Cheers,

Eric