04' Aveo O2 Sensor loose???

[87Aveo]

Hey folks. I recently noticed a small decrease in fuel efficiency in my 2004 Aveo. Sometimes up to about 50 KM less on a tank of gas. Now, I believe I have a mild exhaust leak. There is a sort of sputtering noise from somewhere in the exhaust (I have yet to take it in to get it fixed) which could account for some fuel loss, correct? But also, I recently replaced my stock filter with a Chromeintake CAI. For those who have purchased this and put it on the 2004 Aveo, you may notice the sensor doesn't fix exactly into the hole on the new chrome one. You have to actually pry or cut out the sensor from the old rubber hose and put it in the new one. I haven't actually found a way to adhere the sensor (is this an O2 sensor?) to the chrome piping yet. I fit it in, and it stays there but it is loose and there is a small gap which allows me to see inside the chrome pipe. Nothing huge, but probably about a half centimetre gap. So I was wondering if this would account for any sort of lower fuel economy? And if so, what would be a good way to fill this gap... just some high heat clear sealant/silicone?

[petrified.rabbit]

that is not the o2 sensor, but that is an issue, rtv or silicone sealer should fill the gap.. and fix a problem there.

the o2 is in front of the engine, look in the space between the vavle cover that says etecII and the radiator support, youll see shiny metal covering the exhaust manifold. in the middle of that is a spark plug looking thing with a wire built into it, that is the o2 sensor, you have a 2nd one further down the pipe a well..

depending on where the leak is, it could also be affecting your fuel mileage.. the cai increases power more that fuel economy at all levels (more air more gas) so if you want all mpg, you might want to stick with oem..

[87Aveo]

So what is that bit then? Just curious! He he. And what issue would it cause if it was not filled? I have some leftover RTV or silicone sealer (can't recall which it is) from when I 'Joey Modded' my lights. I will fix it this evening.

I am not too concerned with the fuel economy. 50KM isn't too bad. I plan on getting the exhaust leak checked out later this week too so hopefully that will fix that. I put the CAI in more so for the power increase, which I did in fact notice especially in the higher RPMs.

Thanks for the quick response!!!

[petrified.rabbit]

i'm not sure with your engine, its an intake sensor, either the IAT (intake air temp) which is most likely, or a volume measure, which but i believe you have a map sensor the reads vacuum.. not attached to the intake directly. (i have the maf version car 09+)

its just not good for there to be a leak in the system.. the sensor might be miss reading because of it, or in the case of the maf, it would be mis-metering fuel.. the map sensor reads differently though and would almost account for the leak.

[ontarian_frog]

The IAT sensor controls ignition timing. By having a leak, you're letting warm air enter the engine, the sensor will retard the timing, which affects your fuel economy negatively.

[87Aveo]

Thank you for the replies! I used some leftover silicone from when I did my Joey Modded lights and sealed up the gap all around the sensor. Since I use my trip-ometer religiously, I can usually tell where the fuel gauge is supposed to be in relation to my actual miliage, so I actually noticed right away this morning the difference from fixing it. I drive about 50km to work one way, so it is easy for me to see the difference he he. This seems to have fixed it, but I did notice one thing. Is there a certain direction the actual IAT Sensor has to be facing inside the hose? I mean like should I have rotated the sensor a certain way before adhering it to the chrome pipe, or will any direction suffice? I understand that it's just going to convert the cold air flow somehow, but just curious if the direction that the sensors face would make a difference. Thank you!