My SES light has been on for the past few months, and I finally got it scanned monday. I have a bad 02 sensor, and was just wondering if I've been loosing any power at all. I have 2 new ones on order though. How much power am I loosing if any? Its a front sensor btw.

 

My car wouldn't hardly idle in gear once in closed loop with bad O2's....

Mike

 

You're not losing any power at wide open throttle and in open loop because it ignores the sensors in these modes, but in closed loop, under part throttle, a bad o2 can cause one of the following: bad idle, rough driving (miss/hesitation), increased fuel consumption, etc.
Get it replaced.

 

Alternativley only drive at 100% or 0% throttle Its much more fun that way.

 

everyone says that o2 sensors are not part of the equation at WOT. WHen i had a bad o2 sensor (left bank) the car wuld switch from closed to open loop, where it would run much better. If i gunned it while i was in open loop, it was good. If i gunned it while it was in closed loop and stumbling, the acceleration was CRAPPY. The car would shake so bad it was like magnifying the stumble by a factor of 10.

I never did figure out why. I changed the 02 sensor a few months ago and never had that prob again.

 

But..... If the PCM was "adding" fuel in closed loop with the BLM's, it will continue to "add" fuel in PE mode. If the "faulty" O2 sensors are causing a "false lean" and forcing the BLM's above where they should be, the engine is going to run even richer in PE mode, and that costs power.

In order to answer the question a bit more precisely, it would help to know the exact trouble code you got with the scan. There are many O2 sensor codes that could indicate problems other than an actual O2 sensor failure.

 

Injuneer does the computer not jump to a different Cell block when at WOT? Because when I watch the comp on freescan it seems to and also the computer defaults the integrators and BLMs to 128 steady....

 

If the O2s were over 128 the pcm adds fuel beyond the tune at WOT if below 128 it runs strictly off the tune at WOT. It does this because it assumes that if it was lean before WOT it would be lean at WOT so it adds fuel for safeties sake. If it was pulling fuel it figures that WOT will just be a tad too rich wich is safer than lean so it just leaves well enough alone.

 

how much power could you lose with 2 vacuum hoses slit????

 

What makes the decision for the ECM to go into closed loop?