Can old o2 sensors cause bad mpg?
08-14-12, 09:49 PM
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Can old o2 sensors cause bad mpg?
Ok, I know my o2 sensors aren't bad or else a check engine light would come on but I have a 94 SC4 with original o2 sensors and I'm getting baddd mpg. Almost as bad as my Ford Expedition.
I did a tune up and barely saw an increase in mpg, so can old sensors just be dirty and casuing bad air/fuel mixture?
I did a tune up and barely saw an increase in mpg, so can old sensors just be dirty and casuing bad air/fuel mixture?
08-15-12, 08:40 AM
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absolutely! Be sure to replace them as a set. If the ECU sees one responding faster than the other, it will likely trigger a check engine light. If it doesn't it will assume the fuel mixture is off and compensate for it, decreasing the life of your new sensor.
08-16-12, 03:16 PM
#5
Went to Rockauto, prices all over the board, AWSCI for $35.00 Denso and Delco for twice that. I thought my 93 SC400 was OBD1, they say it has 2 upstream and 2 down stream?
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11-02-12, 03:12 PM
#8
you never said your mileage on the originals. the non heated type found on non-cali odb1 (majority of SC's) are supposed to be replaced every 50k miles for optimal performance and mpg and emissions.
heated type found on the later models and cali models should be replaced every 80-100k miles.
every model is a little different, stick a flashlight down there and take a look.
the 2jzge's with non heated o2's have 2 on the manifold for sure.
I think the vvti's have the same 2 on the manifold and one after the cat, but im not 100% on that.
sc400 no idea, really its best to actually go look at your car, you never know if someone has swapped something around on you, which is becoming more and more likely these days.
heated type found on the later models and cali models should be replaced every 80-100k miles.
every model is a little different, stick a flashlight down there and take a look.
the 2jzge's with non heated o2's have 2 on the manifold for sure.
I think the vvti's have the same 2 on the manifold and one after the cat, but im not 100% on that.
sc400 no idea, really its best to actually go look at your car, you never know if someone has swapped something around on you, which is becoming more and more likely these days.
11-02-12, 04:10 PM
#9
on the VVT-i ones should be 2 before the cats, one for the front 3 cyl., the other for the back 3. also one after the cat. Just need to replace the front 2 if you want to see improved gas mileage, the one after the cat is there just to make sure the cats are working.
for the 1UZ, should be 2 upstream (one for each bank of cylinders) and 2 downstream. Again, for better mpg get the 2 upstream ones.
for the 1UZ, should be 2 upstream (one for each bank of cylinders) and 2 downstream. Again, for better mpg get the 2 upstream ones.
03-25-13, 09:07 AM
#12
on the VVT-i ones should be 2 before the cats, one for the front 3 cyl., the other for the back 3. also one after the cat. Just need to replace the front 2 if you want to see improved gas mileage, the one after the cat is there just to make sure the cats are working.
for the 1UZ, should be 2 upstream (one for each bank of cylinders) and 2 downstream. Again, for better mpg get the 2 upstream ones.
for the 1UZ, should be 2 upstream (one for each bank of cylinders) and 2 downstream. Again, for better mpg get the 2 upstream ones.
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