Oxygen sensor problems?

[hybriDatsun350]

I just recently installed a Scangauge on my car, and I have been trying to figure out what my car likes as far as gas mileage is concerned. In doing this, I have noticed that my car goes into open loop at anything above about half-throttle. I understand that Honda's (as well as most other cars) go into open-loop under WOT, but my car is doing it long before WOT. I am wondering if this could be a sign of the O2 sensors being bad? Any ideas? Thanks for your help.

[GasSavers_BEEF]

I am just assuming on this one (and please take it as such) but I would think maybe your throttle position sensor more than anything.

as far as I know, that is what tells your cars ECU that it is at WOT or close to it. I may be wrong but it may be worth looking into.

[GasSavers_RoadWarrior]

Maybe it's a bit glitchy if you seldom go into that range. Could try just sitting in the car with the engine off and stomping up and down in the gas pedal for a minute, see if that clears any oxidation and wears it in.

[petty]

When oxygen sensors goes bad, your car runs differently and your mileage may vary. Gasoline engines run best when the air-fuel mixture is correct. And the oxygen sensor detects the air-fuel mixture of a gasoline engine by measuring the amount of oxygen in the exhaust gas. You may try checking the diagnostic codes as well.

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Car Solutions.

[Ford Man]

After looking at your mileage log I don't think you have a problem with the 02 sensor. When an 02 sensor goes it is not uncommon to lose 20-30% fuel efficiency. Your numbers don't reflect anything even similar to that.

[hybriDatsun350]

I sat down and tried pumping the accelerator with the engine off because I figured that couldn't hurt. It didn't seem to change anything, but it was worth a try.

Does anyone else with a Honda, or any other car for that matter, notice their car going into open-loop before it should be?

Thanks for the help guys!

[GasSavers_BEEF]

try this, set up your scangauge for A/F ratio. that will tell the story. it should be around 14.7 or so. then give it enough throttle to get it into the open loop that you described. that number should change. mine at WOT is reading 12.6 or so. which means it is sucking gas. I don't think that A/F ratio is one of their normal choices so you have to input some code for that. they have a list of X-gauge comands on the website scangauge.com.

that will tell you if you are actually in open loop or if for some reason it is just displaying it wrong. after that I would still suspect the TPS sensor but that is just me.

[hybriDatsun350]

I don't think you can get AFR on a Honda (Acura). I noticed that they have the AFR x-gauge for GM cars though. I will see what I can find out. Thanks.

[GasSavers_BEEF]

didn't think about the whole honda vs chevrolet thing. maybe A/F ratio isn't the best way for you to see. maybe you could see on your gallons per hour. eas up on the pedal to where you hit open loop and see if there is a big jump in gas used. maybe it is gallons per minute (can't remember)

hopefully some of this is helpful

[GasSavers_BEEF]

a revelation hit me. if you problem is the TPS sensor (as I think it may be), you can just look at TPS on the scangauge and see what it says as far as the position. at no throttle, it should be readint zero (or near to it) my wife's honda element (2004) reads 9 at no pedal. at regular driving it reads 33 which I think is a percent value.

if you are having problems then these numbers would be skewed. I am just bringing this up because it is what the ECU is seeing and it is easy to do and doesn't cost anything since you already have the scangauge