My question is:

Does your 02 sensor effect gas mileage?

I have a 97 del sol. Installed ebay headers [only had one bung hole for one 02]
My car has 2 02 sensors. I took off the 02 sensor that was after the CAT.

Is this bad? i really don't mind the CEL but i'm wondering if this is effecting gas mileage.

 

First thing... Please read the Forum Rules sticky. Create threads with proper subject matter, not just "help" or "one question"...

On to your issue. The second O2 is strictly for emissions purposes, it will not effect gas mileage.

I would suggest fixing the CEL. You could have other problems down the road and wouldn't know because your CEL would already be on, and it just looks goofy. To fix it you have a few options....

1. Search for an O2 simulator that plugs in where the 02 used to.
2. Weld in a bung

GL OP

 

okay, thanks. Btw, before i the header, i didn't have any issues with the car, no cel, the car ran perfect. The cel right now is because of 1:Header flow for the 1st 02 and 2:i don't have the 2nd 02 plugged in

 

Flow will not throw a CEL.....

The second 02 is strictly designed to measure hydrocarbons for emissions purposes. This in turn shows if your catalytic converter and other emissions equipment is functioning properly.

I assure you that if you scan your car it will be throwing a single code caused by the 2nd 02.

Did you eliminate the cat when installing the header? Test pipe?

 

yes

 

just plug the secondary o2 back into the harness and ziptie it up to a)something on firewall b) something on the engine like intake mani c) anywhere it will reach

no need to weld a bung in or anything, secondary o2 is meant to be after cat where the air should be somewhat clean so dangling in the open will trick it to think its reading clean exhaust and Bam

NO CODES

 

Can anyone verify this? sounds logical to me.

 

yes i would like to know this too.

 

I believe that dangling the secondary O2 sensor free should throw a CEL code because this sensor will detect high O2 levels (=very very lean condition). This will trigger a code by the ECU because high O2 levels are not expected at the secondary O2 sensor when the same condition does not exist at the primary O2 sensor.

 

always worked for me, on a few eks so far. I hate obd2 cars and always find ways around stuff like that

 

How much power are you putting out?

 

I'm not sure if this have to do with my question. I'm running on a stock d16y7 with a header. [106hp via Honda]

 

The first 02 sensor is the only one that really has any bearing on your gas mileage. It sees your AFRs in the exhaust pre-catalytic converter and adjusts fuel based on that. The second O2 merely keeps an eye on the catalytic converter. As long as it sees clean air and a certain amount of heat, it won't throw a CEL. Most people zip-tie this 02 sensor near the exhaust but let it dangle in free air. There are also 02 delete kits available online for very little $$ if you want to go that route.

 

yes, youre o2 sensor effects your gas milage. I drive a 01 Acura Integra GSR and before i installed my new o2, i was getting about 170 miles to the tank. thats fu*king HORRIBLE! after i installed my new o2, im getting around 250-275 miles to the tank. it has improved 100 miles to the tank.

 

can a faulty O2 sensor cause your car to lose power?