[V8] power drop outs

[nicolcs at aol.com]

OK Mike, I'm a little confused by your note...
There are usually three wires on an O2 sensor.  1) Power to the heater (+12), 2) ground, and 3) Output from the sensor (0 to 1 volt). 
 
Normally the output swings above and below .45 volts, say from .2 (lean) to .7 (rich).  The sensor acutally generates this voltage internally.  If you disconnect the sensor, most ECMs substitute a value of .45 volts so the car will run - this is what Ingo suggested you do to see if the car straightens up.  If it does, the sensor is likely bad. In my V8, the sensor got slow (response time)and this caused the car to surge.  The other common 02 failure is a skew, where it reports richer or leaner than actual so when the ECM tries to correct to center, the AFR is leaner or richer than it should be. 
 
If the car doesn't straighten up when the 02 is disconnected, suspect the temp sensor, MAF, intake air leaks after the MAF, or a leaking injector.
 
Craig Nicol
 
 

On Apr 6, 2007, at 12:38 PM, Michele_Deltergo at KeyBank.com wrote:

>
>
> The first suspect appears to be the 02 sensor.  Just checked it is  
> getting
> power fine, problem is that it is passing almost all of it  
> through!  At
> start almost 3 volts going to 10 on warm up.  Seems to fit the  
> symptoms of
> OK running when cold (I think the ECU ignores 02 for a time) then  
> crappy
> when warm.   I thought most failed at no signal vs 100% signal,  
> must be
> shorted quite well.   Disappointing as 02 is only 7,000 miles old,  
> but good
> it that is the fix.  Unfortunately 02 is in like the original and  
> getting
> it out will be fun.
> Mike
>
>
>
>
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