Changing my Oxygen sensors question?

[38sho]

I'd check alignment, tire pressures, tire rolling resistance and weight, and any brakes dragging before I started replacing engine sensors that are working to the computer's standards to try and improve mileage.


how are the spark plugs? sorry I kind of scanned over the entire thread and just read begining


also if you do change O2 sensors, stay away from Delco, they are overpriced, when you open the aftermarket sensors they usually say Denso on them anyway lol.... reboxers

cut the middle man and just get the denso OE style from the get go..... they are excellent products

 

[pbm]

I ordered the Denso OEs from Autoparts123 and used a 15% off labor day coupon. Both sensors came to less than $80 with the coupon and I even bought a few other things because of the free shipping. I'll let you know if there is an improvement..

 

[ltslimjim]

^Awesome, glad you went with Denso for that price.

 

[wrcsixeight]

Originally Posted By: 1 FMF

in short, you can have a bad O2 sensor and not have a check engine light (CEL) or diagnostic trouble code (DTC) stored. What's happening is the O2 sensor is sluggish and not responding quickly enough under all operating conditions, not enough to throw a CEL but enough to cause high NOx and fail emissions. They say a sensor signal should rise from 0.175 to 0.8 volts, should cycle at least 16 times within 10 seconds at 2000 rpm, and to verify sluggishness you need a scope and do a snap throttle test- from idle mash the pedal wide open then release quickly, if the 02 sensor takes longer than 50ms to respond it's sluggish and should be replaced.


+1. I've read this in many different places as well.
Here is one:
http://www.aa1car.com/library/o2sensor.htm

I recently passed a Ca Smog test, but was on the high side of HC's. Afterward I pulled out the 4 year old Bosch 02 sensor and installed an NTK. Apparently Bosch 02 sensors do not work well with Mopar. Wish I replaced it before and got better numbers.

 

[pbm]

I finally got around to looking at the O2 sensors and it appears to be more difficult to change than I thought.
The upstream sensor is in the rear of the (3.1) motor.
The wiring seems to go up through a tube to the EGR valve???...does this sound right to the more knowledgeable guys???
The tube is wrapped in a heat shield type cloth (asbestos??) that fell apart when I pulled it.
My aftermarket Denso O2 sensor is supposed to be an OE replacement but the connector isn't visible. Is it necessary to remove the EGR valve to replace the upstream connector?
The downstream connector is after the cat. conv. and seems doable from below the car.

 

[mechanicx]

There should be the connector pigtail coming off the original O2 sensor. It is suppose to be anchored to coil pack bracket and will slide off. There is a I think blue plastic "connector assurance" tab in the connector that you have to pull out to disconnect the connector. Maybe your wiring harness got misrouted when someone was working on that area but you should be able to find the O2 connector and disconnect it without having to disconnect anything else. You will probably need an O2 socket tool to get the sensor off.

 

[pbm]

Mechanicx: I found the upstream O2 sensor when I double checked in better lighting conditions. What I was originally looking at was an exhaust tube to the EGR valve...it screws in like an O2 sensor and fooled me at first.. Thanks for the tips.

 

[Jim Spahr]

Like mechanix said a while back, I wish you had gone with the O2 sensors by AC/Delco. GM cars are not sensitive to brake pads, like Toyota and Honda cars are. But they are sensitive to the type of O2, spark plugs, and PCV valves you use. AC/Delco will work better and last longer that the other brands, esp. Bosch. I don't know about Denso specifically.