Bad O2 Sensor?!?= Bad Gas Mileage
#1
Bad O2 Sensor?!?= Bad Gas Mileage
So I was thinking....
Next thing I was thinking, I might have bad O2 sensors. Ive read a little on here and I know with having bad O2 sensors you will loose out on gas mileage. Now I dont know how to determine that I have bad O2 sensors, so i went out to my car and snapped a couple pics with hoping you orgers can help me out, considering I was looking at the prices of purchasing new O2 sensor from Bosch @ $130 a pop for each one.
Heres the 1st front O2 Sensor (behind the radiater)
Now heres the 2nd rear of the motor O2 sensor (close to the firewall)
Last one, under the car. 3rd O2 Sensor
Dont mind the oil. I just recently fixed a bad oil leak about 3 weeks ago and tried cleaning everything off the engine and from the undercaraige with Purple Power Degreaser Cleaner, but its a bit** to get off especially after it has been leaking for about 5 months, so I just decided to let it burn/ fall off on its own.
So any suggestion after looking at the pics of the O2 sensors would be greatly appreciated. As well anything else you guys think i can do to improve my gas mileage??
Thks,
Luis
- 4 brand new tires
- 6 new NGK Iridium Spark Plugs
- Abt 38lbs of air in the tires
- Car isnt pulling ( was alligned when had new tires installed)
- fresh oil change
- New valve cover gasket ( no more crazy oil leak)
- Running E93 gas (premium)
- New Berk Short Ram Intake
- Clean MAF and TB....
Next thing I was thinking, I might have bad O2 sensors. Ive read a little on here and I know with having bad O2 sensors you will loose out on gas mileage. Now I dont know how to determine that I have bad O2 sensors, so i went out to my car and snapped a couple pics with hoping you orgers can help me out, considering I was looking at the prices of purchasing new O2 sensor from Bosch @ $130 a pop for each one.
Heres the 1st front O2 Sensor (behind the radiater)
Now heres the 2nd rear of the motor O2 sensor (close to the firewall)
Last one, under the car. 3rd O2 Sensor
Dont mind the oil. I just recently fixed a bad oil leak about 3 weeks ago and tried cleaning everything off the engine and from the undercaraige with Purple Power Degreaser Cleaner, but its a bit** to get off especially after it has been leaking for about 5 months, so I just decided to let it burn/ fall off on its own.
So any suggestion after looking at the pics of the O2 sensors would be greatly appreciated. As well anything else you guys think i can do to improve my gas mileage??
Thks,
Luis
Last edited by mrfxho; 01-25-2011 at 10:38 PM.
#2
You will almost certainly get a check engine light if a O2 sensor is bad. This is one of the main things the computer looks for. If you don't have a CEL I highly doubt its your O2's.
Pictures also will not tell us anything since the heating element/sensor is inside the bung hole in the exhaust piping.
Alot depends on your driving habits. When I had my Max, I got about 260-270 to a tank, and that was about 75% HW and 25% CITY. I had a heavy foot.
You also might want to lower your PSI a little in your tires. We are only suppoed to have something like 32 PSI in each tire.
Pictures also will not tell us anything since the heating element/sensor is inside the bung hole in the exhaust piping.
Alot depends on your driving habits. When I had my Max, I got about 260-270 to a tank, and that was about 75% HW and 25% CITY. I had a heavy foot.
You also might want to lower your PSI a little in your tires. We are only suppoed to have something like 32 PSI in each tire.
#4
These are very good miles. I'm getting about 260-280 now with all city driving. To OP, I guess few other things to check would be air filter, extra weight, Anything wrong with exhaust backpressure?
#5
as far as weight...i can chime in on that too...ive been riding around in my car with a crate full of BS, a jack, tools in the trunk. possibly air filter i agree with or maybe a clogged cat convertor. is your car doing anything out of the norm? like VQ said a bad o2 sensor warrants a SES light, and you said you dont have any so...
#7
You will almost certainly get a check engine light if a O2 sensor is bad. This is one of the main things the computer looks for. If you don't have a CEL I highly doubt its your O2's.
Pictures also will not tell us anything since the heating element/sensor is inside the bung hole in the exhaust piping.
Alot depends on your driving habits. When I had my Max, I got about 260-270 to a tank, and that was about 75% HW and 25% CITY. I had a heavy foot.
You also might want to lower your PSI a little in your tires. We are only suppoed to have something like 32 PSI in each tire.
Pictures also will not tell us anything since the heating element/sensor is inside the bung hole in the exhaust piping.
Alot depends on your driving habits. When I had my Max, I got about 260-270 to a tank, and that was about 75% HW and 25% CITY. I had a heavy foot.
You also might want to lower your PSI a little in your tires. We are only suppoed to have something like 32 PSI in each tire.
#9
Ok so im really leaning to saving up a lil money and purchasing and purchasing all new 4 O2 sensors.
Where would be the best/cheapest to buy these O2 sensor without it costing me a arm and a leg.
I want it to be of good quality as well but not extremely expensive. Those who have replaced there O2 sensors, whcih did you guys decided to use?
One more thing, is it necessary to replace all four O2 sensors if I am getting bad gas mileage or are there certain one that I can replace which would helop me in this field, like just replacing each one in the headers?
Thks,
Luis
Where would be the best/cheapest to buy these O2 sensor without it costing me a arm and a leg.
I want it to be of good quality as well but not extremely expensive. Those who have replaced there O2 sensors, whcih did you guys decided to use?
One more thing, is it necessary to replace all four O2 sensors if I am getting bad gas mileage or are there certain one that I can replace which would helop me in this field, like just replacing each one in the headers?
Thks,
Luis
#10
Maybe you mentioned it previous, but how many miles are on your car? O2 sensors are said to be a 100,000 mile replacement part. I am assuming you are at least at that. It certainly wouldn't hurt to replace the O2 sensors if they are original. I found better prices on either eBay or RockAuto.com.
What is E93? Is that an Ethanol blend? I try to avoid that, if possible.
Also, pay attention to those CEL's and what code that AutoZone tells you they are. Just write down the codes (It will be in a PXXXX format...) and then come here and do a search for it. That may help...
I think I get pretty bad gas mileage, IMO. I couldn't tell you the last time I got over 20mpg, but I do drive all city. I don't calculate it out exactly when I do simple math and I know its not going to be 20mpg.
Saying "I get XXX miles on a tank" isn't really helpful as one person may drive on a tank of gas until the Low Fuel light comes on which means there are still a few gallons in the tank and others may run it and coast into the gas station on fumes. Actual MPG numbers are the best way to compare apples to apples.
What is E93? Is that an Ethanol blend? I try to avoid that, if possible.
Also, pay attention to those CEL's and what code that AutoZone tells you they are. Just write down the codes (It will be in a PXXXX format...) and then come here and do a search for it. That may help...
I think I get pretty bad gas mileage, IMO. I couldn't tell you the last time I got over 20mpg, but I do drive all city. I don't calculate it out exactly when I do simple math and I know its not going to be 20mpg.
Saying "I get XXX miles on a tank" isn't really helpful as one person may drive on a tank of gas until the Low Fuel light comes on which means there are still a few gallons in the tank and others may run it and coast into the gas station on fumes. Actual MPG numbers are the best way to compare apples to apples.
#15
yea, forgot to mention that I drive 85% city and 15% highway (rare bc sometimes I go a entire tank without hitting the highway) but I go into the gas station when my gas light turns on and my speedo is blinking saying theres --- MPG left.
My life pretty much is going to work (15-18 min away from home and abt 9 miles away), going to my girls house every other night (7 mins away and abt 4 miles away), sis house @least once a week ( 2 mins away and abt 1 1/2 mile) and occasionally on the weekend me and my girl go out or to a friends house and thats abt my weekly travel. So LOTS of city driving. Maxxed I have ever got on a full tank will be 230-240 and thats driving like a grandpa without stepping on it.
So which would be the only 2 O2 sensors I would have to replace mahanddeem and yankeefan13?
VQPOWER, which are the primary two O2 sensors that you reccommend replacing?
Thks,
Luis
My life pretty much is going to work (15-18 min away from home and abt 9 miles away), going to my girls house every other night (7 mins away and abt 4 miles away), sis house @least once a week ( 2 mins away and abt 1 1/2 mile) and occasionally on the weekend me and my girl go out or to a friends house and thats abt my weekly travel. So LOTS of city driving. Maxxed I have ever got on a full tank will be 230-240 and thats driving like a grandpa without stepping on it.
So which would be the only 2 O2 sensors I would have to replace mahanddeem and yankeefan13?
VQPOWER, which are the primary two O2 sensors that you reccommend replacing?
Thks,
Luis
#16
Like the other knowledgeable people said here : the only 2 important O2 sensor are the front (or upstream) sensors , both of which are before the 2 pre-cats..Don't worry about the downstream ones cause they ONLY monitor the pre-cats function , and if they're bad you only get SES light.....I ordered mine from rockauto.com and they were Denso....Forget about eBay craps...
#17
I will replace all 4 sensors if I had the money... BTW the "knowledgeble folks" don't know that O2 get lazy and may never thro a code. They last at best 100K and if u have 100K on them time to change. U will recover the cost over an yr with more MPG.
Check your coils too they may be faulty running the engine rich with all the richness (fuel) going downstream into the O2 and cats.
Check your coils too they may be faulty running the engine rich with all the richness (fuel) going downstream into the O2 and cats.
#18
Like the other knowledgeable people said here : the only 2 important O2 sensor are the front (or upstream) sensors , both of which are before the 2 pre-cats..Don't worry about the downstream ones cause they ONLY monitor the pre-cats function , and if they're bad you only get SES light.....I ordered mine from rockauto.com and they were Denso....Forget about eBay craps...
I will replace all 4 sensors if I had the money... BTW the "knowledgeble folks" don't know that O2 get lazy and may never thro a code. They last at best 100K and if u have 100K on them time to change. U will recover the cost over an yr with more MPG.
Check your coils too they may be faulty running the engine rich with all the richness (fuel) going downstream into the O2 and cats.
Check your coils too they may be faulty running the engine rich with all the richness (fuel) going downstream into the O2 and cats.
now i just need to know which one you guys are talking abt lol.
By the way, the car has 145xxx miles on it. My grandma gave me the car back in 2007 bc she said it was waisting too much gas for her and she was going to sell it but offered it to me first with only 80xxx miles on it for $4,000 since im family lol.
#19
can you guys post pics of which ones are which. bc I found this in a stciky thread
now i just need to know which one you guys are talking abt lol.
By the way, the car has 145xxx miles on it. My grandma gave me the car back in 2007 bc she said it was waisting too much gas for her and she was going to sell it but offered it to me first with only 80xxx miles on it for $4,000 since im family lol.
now i just need to know which one you guys are talking abt lol.
By the way, the car has 145xxx miles on it. My grandma gave me the car back in 2007 bc she said it was waisting too much gas for her and she was going to sell it but offered it to me first with only 80xxx miles on it for $4,000 since im family lol.
#20
#21
#25
i dont know the answer to this and i dont want to give you bad information, but im willing to guess that it could if it pulls timing or something.
that being said, you're gonna wanna look into that sooner rather than later.
i can however tell you that maximas are pretty bad in the city. its a lot of car to get moving every time you stop.
#26
start with simple to "more serious" things....
1.Reset and see if that code comes back or not
2.Check the fuel you use..(don't put less than 93 octane)
3.Check oil level periodically (does you car burn oil?)
4.Check for oil or vacuume leaks
5.Have the timing checked
1.Reset and see if that code comes back or not
2.Check the fuel you use..(don't put less than 93 octane)
3.Check oil level periodically (does you car burn oil?)
4.Check for oil or vacuume leaks
5.Have the timing checked
#27
I have codes for bad 02's also, gonna save up and get all 4 done with me having 162k on a 03. drive 35-40 miles a day 4 days a week. not including weekend trips. if i take the car out of town i get about 460+. city is 385 on a full tank
#28
the Walker brand sensors are $60-$80 here & work fine:
http://www.oxygensensors.com
http://www.oxygensensors.com
#30
WOW
I just picked up a 2000 se 5 speed in the summer with 166,xxx + , I do have a SES light for the post cat 02 sensor but my average per tank of gas is anywhere between 380 to 450 miles depending on how much I have to drive city... Man I was thinking I had a bad gas millage...
I just picked up a 2000 se 5 speed in the summer with 166,xxx + , I do have a SES light for the post cat 02 sensor but my average per tank of gas is anywhere between 380 to 450 miles depending on how much I have to drive city... Man I was thinking I had a bad gas millage...
#31
I think Maximas just have crap mileage in town. I have an '02 GLE and only get between 15-17mpg average with almost all city driving. I measure my mileage by dividing miles driven between fill ups by gallons purchased.
#32
WOW
I just picked up a 2000 se 5 speed in the summer with 166,xxx + , I do have a SES light for the post cat 02 sensor but my average per tank of gas is anywhere between 380 to 450 miles depending on how much I have to drive city... Man I was thinking I had a bad gas millage...
I just picked up a 2000 se 5 speed in the summer with 166,xxx + , I do have a SES light for the post cat 02 sensor but my average per tank of gas is anywhere between 380 to 450 miles depending on how much I have to drive city... Man I was thinking I had a bad gas millage...
#34
http://www.autohausaz.com/html/emiss...n_sensors.html
As an oxygen sensor ages, contaminants from normal combustion and oil ash accumulate on the sensing element. This reduces the sensor's ability to respond quickly to changes in the air/fuel mixture. The sensor slows down and becomes "sluggish".
At the same time, the sensor's output voltage may not be as high as it once was, giving the false impression that the air/fuel mixture is leaner than it actually is. The result can be a richer-than-normal air/fuel mixture under various operating conditions that causes fuel consumption and emissions to rise.
The problem may not be noticed right away because the change in performance occurs gradually. But, over time, the situation will get worse, ultimately requiring the sensor to be replaced to restore peak engine performance.
At the same time, the sensor's output voltage may not be as high as it once was, giving the false impression that the air/fuel mixture is leaner than it actually is. The result can be a richer-than-normal air/fuel mixture under various operating conditions that causes fuel consumption and emissions to rise.
The problem may not be noticed right away because the change in performance occurs gradually. But, over time, the situation will get worse, ultimately requiring the sensor to be replaced to restore peak engine performance.
#35
Try getting a new fuel filter and see if your cat is clogged after. I get between 240-280 at the most with 60% highway and 40% city and my car pulls codes every other week about to install my obx headers maybe they will help.
Last edited by Sneaky Green; 01-30-2011 at 04:58 PM.
#38
Member who somehow became The President of The SE-L Club
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My life pretty much is going to work (15-18 min away from home and abt 9 miles away), going to my girls house every other night (7 mins away and abt 4 miles away), sis house @least once a week ( 2 mins away and abt 1 1/2 mile) and occasionally on the weekend me and my girl go out or to a friends house and thats abt my weekly travel. So LOTS of city driving.
Take the car on a good long trip and measure your MPG.
P0011 - Camshaft Position Sensor controls Fuel Injection Timing.
It's possible that's having an impact on your mileage.
#39
There is a way to determine if an O2 sensor is working properly. Lightly clamp the wrench hex in a vise with the exhaust element pointing up. With a multimeter, determine which leadwire is the heater (low resistance to ground) and which is the sensor output (very high resistance or open circuit indication. Set the multimeter to the 2 volt range and connect the + lead to the sensor leadwire adn the - lead to ground (the sensor housing or vise). Heat the sensor element with a propane torch (Bernzomatic). Do not use an acetylene torch). The element can be heated to a dull red heat in a normally lighted room. As the flame is removed from the element, up to one volt will be generated as oxygen in the air gets to the hot element. You can play the flame back and forth over the sensor element and watch the voltage cycle between zero and one volt. The flame envelopes the sensor and prevents oxygen from getting to it. If this works, the sensor is good.
BernieK
BernieK
#40
I'm with the OP barely pulling 220 out of a tank with almost all highway driving and I think I'm going to look into replacing the two primary o2 sensors as well.