O2 Sensor / fuel economy

[Alero_1986]

When I bought my car last year I took it out on the highway for a test drive. Since it was a new car I just wanted to experiment with it. I hit 160km/h right on the dot and the SES light came on right at that instant. I found it strange that the light had come on right at 160. I asked around, and recieved mixed answers. A couple of mechanics explained that on some models the SES would kick in at a certain speed. Others thought that it sounded ridiculous. I took my car to my brothers high school and set up their code reader. The scan returned that I had a bad O2 sensor. I was still curious to know if 160kph set off the light. I was informed that one way to find out would be to reset the code and if it was triggered again I would know it was the O2 sensor. This was about 4 or 5 months ago. since then this code has not returned, and I have had no need to drive 160:(

When I was checking the forums here I noted that other people were getting up to 30+ mpg out of their 2.4's. I don't know how accurate people are finding their fuel economy though...
I have an relatively accurate program for calculating my fuel economy per fill-ups, and at best I've gotten 29mpg for %100 highway driving. I usually drive 50/50 highway/city, and I average 21-23 mpg. I have experimented with different gas, and driving technique, and not noticed any great improvement. Are this numbers within expected range of a 2.4L MT
Should I expect the SES light to notify me if there is any failure in the sensor? or is there another way to check them?
I understand the the upsteam sensor would play the larger role in decrease gas mileage.
does anyone have any advice? I don't want to spend money on replacing parts that are not broken. Canadian tire sells the upstream sensor here for $68 CAD. I found a set of new bosch sensors on ebay for $36 shipped

[Alero_1986]

My only MOD is a WAI. I checked the gas mileage before and after, and noticed little change.
thanks for any advice..

[[ion] C2]

that's the mileage I get

[Alero_1986]

would the SuperC not drop your values a little?

[Oldsman]

my 2.4 when it was stock would get 24 in town and 28 on the highway. after doing CAI, TB, 2.3 manifold and exhaust i got up to 32mpg on the highway. Then after cams and head and header and etc. i still get 32mpg on the highway

[[ion] C2]

would the SuperC not drop your values a little?

not if i don't go into boost, next time i fill up this week i'm going to take it easy (under 3k rpms all the time) and see what kinda mileage i can get with this with normal city driving

[Alero_1986]

so MODs are actually helping your economy? that's decent.

[[ion] C2]

making her breathe better helps :)

[Alero_1986]

my 2.4 when it was stock would get 24 in town and 28 on the highway. after doing CAI, TB, 2.3 manifold and exhaust i got up to 32mpg on the highway. Then after cams and head and header and etc. i still get 32mpg on the highway


I was considering going this route when cash permits these MODs.
how much do you estimate your set-up would run? and what gains did you get?

[Alero_1986]

C2;312368']making her breathe better helps :)


true thanks. I have a new WAI, and it's pretty clean. I don't have any maintenance records, so I was gonna check the fuel filter. Exhaust seems fine. When she goes or money permits I'd like to buy headers, high flow cat, magnaflow muffler, and custom 2.5 piping

[Alero_1986]

has anyone heard or experienced a SES light comming on after a set speed (ie. 160kph)?

[misslindseysue]

SES only comes on for part failures that affect emissions. SVS will light for anything else. OBD will detect a bad sensor, but it may become quite slow before it crosses the threshold to set the light. At 160 you may have been dumping so much fuel that something got screwy.
Both 02's will afffect fuel economy. Upstream is the biggest contributor, but downstream is used for 'fine tuning' if you will. My SES only ever comes on when I get gas. And I have my own scan tool at work, so I just reset it.

[Gr1m]

fuck, im lucky to get like 16mpg with my car

[misslindseysue]

Oh - and: I had a V6, but I averaged 28mpg with probly 75/25 highway/city.

[Oldsman]

I was considering going this route when cash permits these MODs.
how much do you estimate your set-up would run? and what gains did you get?

with the mods and gaskets and head work i probably have about $1500 in the motor and gained about 20-30hp approx

[Redog]

Enigne mods do help with HP and fuel ecomony.

With the increase HP and not using it on the highway, your RPMs will stay down at higher rates of speed. My car ran at 2750 at 70 mph, now I have to get upto 85 (which I rarely do) to run that same RPM. I stay around 2000 at 70.

160k's is just a tab under 100 mph, why you were going that fast IDK, but it could be that the SES light came on since you probably had the car under WOT and still climbing. Your O2 sensor was probably on it's way out, but the extra exhaust pressure just set it off

[jayson_waltz]

At that speed the car throws an excessive speed code, but its invisible. It doesn't turn on a light, its one of those black box things.

[01silveralero]

C2;312368']making her breathe better helps :)

better than choking her to death :p just like sex gotta let her breathe :lol:

[01silveralero]

Enigne mods do help with HP and fuel ecomony.

With the increase HP and not using it on the highway, your RPMs will stay down at higher rates of speed. My car ran at 2750 at 70 mph, now I have to get upto 85 (which I rarely do) to run that same RPM. I stay around 2000 at 70.


mine ever since i got it has been at around 2k rpm at 70 maybe thats one reason she's a freak :p

[Alero_1986]

My SES light is back on again... and It looks like I'm going to need a new sensor. What are the best parts to buy? Canadian tire sells the upstream and downstream sensor for $68 a piece. I was looking on ebay, and I can get a 'standard motor co.' upstream sensor for $26+shipping. I know alot of people swear by OEM parts, so if that's the case can anyone tell me if the extra dollars are worth it for a delco O2 sensor? I have yet to check dealership prices, but I have a pretty good feeling that it's not cheap. I noticed that AC DELCO, bosch, NTK, and standard motor co where pretty popular brands to choose from. thanks