Bad 02 sensor?

[KB_GT]

Car is running very rich at the initial start-up. The car usually starts and immediately shuts down. AFR's around 10-11 at idle. If I can get it into drive quick enough and hit the throttle it will not die. I can then drive it around the block until the AFR's even out around 14-15 and it will have no problem idling.

I think I may have a bad 02 sensor. Can anyone confirm?

images from a datalog of one start-up where it stayed on, although very rich.

http://i.imgur.com/sPgcL.jpg

http://i.imgur.com/xF7UD.jpg

Thanks.

 

[01yellercobra]

When you say first start up do you mean when it's cold or anytime you start it? It would be better if you could post the actual logs. And more PIDs in the datalog would help. Like MAF counts, rpm, engine temp, fuel trims, etc.

 

[KB_GT]

When you say first start up do you mean when it's cold or anytime you start it? It would be better if you could post the actual logs. And more PIDs in the datalog would help. Like MAF counts, rpm, engine temp, fuel trims, etc.

It's happens anytime I start it.

I'll see if I can get it to stay on and log more PID's.

Thanks

 

[01yellercobra]

If it was a sensor then I wouldn't think you'd have the problem when it's cold. The computer is in open loop until the coolant reaches a certain temp. So it's not using the O2's during that period of time. I think there's a start up table in there where the time before switching to closed loop can be changed. Who tuned the car?

 

[da2k17]

im having a similar problem but mine will come and go, during driving and idle. think bad sensor or wire. the thing i dont understand is my tuner said nothing can affect (closed loop?) my tune so ive spent the past few weeks trying to figure it out.

my AF #'s are similar to yours so im interested in seeing what you figure out.

 

[01yellercobra]

im having a similar problem but mine will come and go, during driving and idle. think bad sensor or wire. the thing i dont understand is my tuner said nothing can affect (closed loop?) my tune so ive spent the past few weeks trying to figure it out.

my AF #'s are similar to yours so im interested in seeing what you figure out.

It won't affect your open loop operation at WOT. Well, it shouldn't anyway. The ECU doesn't use the sensors when your foot is on the floor.

 

[da2k17]

It won't affect your open loop operation at WOT. Well, it shouldn't anyway. The ECU doesn't use the sensors when your foot is on the floor.

but it will affect casual driving? thats what im having an issue with, at wot everything is normal its my drive ability thats in the tank.

 

[01yellercobra]

but it will affect casual driving? thats what im having an issue with, at wot everything is normal its my drive ability thats in the tank.

Yes. It will affect part throttle. Have you checked the basic stuff? Plugs, vacuum lines, etc.

 

[da2k17]

Yes. It will affect part throttle. Have you checked the basic stuff? Plugs, vacuum lines, etc.

yep.
http://www.svtperformance.com/forum...otor-ran-fine-now-like-crap-running-rich.html

 

[01yellercobra]

Are you still running your EGR?

 

[da2k17]

no. and using a triple return system.

 

[KB_GT]

I was using the KB "Big Tube Kit" that goes down into the front bumper cover and when I removed that and put the filter under the hood it didn't die as easily. When I got it to stay on I let the car idle until the AFR's evened out around 14-15 and then took it for a spin. It drove normal and when I got back I turned the car off and then back on with no problem at all. The next day it drove to work fine but on the way home in 3rd gear (4r70w) at a constant speed the AFR's spiked around 17-18 and it felt like the car was bucking for a second and then it stopped and AFR evened back out around 14-15... Today I replaced an 02 sensor and then the idle went bad again... The car was cold when I started it after the sensor install. I do have the EGR.