Low CC

[Carrollss94]

Hey guys,

So my car is ideling rough and it smells like it’s running rich. Had this problem for a couple weeks now. Originally started with a bad MAF but I’ve since replaced that. Started blowing a code for the O2 so I replaced that too. Car still doesn’t like to idle. Replaced the IAC and air temp sensor. My CC is super sluggish- At idle it seems like it won’t move at all and even driving like a crazy person it will only climb between 1-5ish per frame and sometimes it still just stays on a number and won’t move for a good 15-30 seconds. Thought it was still the O2 so I put another new one in and it didn’t improve the CC any. I find it hard to believe that I got 2 bad new O2 sensors. Any ideas??

 

[rag231]

TPS ( Throttle position sensor) set correctly?

 

[Carrollss94]

TPS is at .46

 

[earlbrown]

It's easy to believe you have 2 bad sensors if they aren't a Delco, or better yet, a Denso.


If you're swapping in Boschs or no-name O2s, I'd see about getting a good one instead.

 

[Carrollss94]

They were Bosch....

 

[Pronto]

From Vortex Buicks.
cc = Cross Counts
Cross Counts are the number of times that the factory O2 sensor has crossed from lean to rich across the stochiometric point (0.441v) during the sample rate of the scan tool. The more active the sensor is, the better job the ECM will do in keeping the A/F at the desired stochiometric ratio for idle and part throttle driving. At wide open throttle, it is not used. Many scan tools may show this number as a cumulative addition so that the first frame may be 10 and the second may be 30 which means the second frame was actually 20. When the total reaches 255, it resets to zero and starts over.
Given that a tool like the ScanMaster samples at approximately 1.4 second intervals and more sophisticated tools like PowerLogger may provide 20+ fps, one must take this into consideration when looking at the results.
Something like 10-40 cross counts per 1.5 seconds is probably normal. An O2 sensor that is sluggish and consistently is on the low end (count-wise) should be replaced. O2 sensors are cheap and it does not cost much to replace one periodically anyway. If you don't, gas mileage and drivability will soon go down hill.
As stated prior, leaded racing fuel will often drastically shorten the life of the O2 sensor. Symptoms are reduced output, sluggish cross counts, and/or a check engine light. Many believe the Denso sensors resist degradation much longer than do the factory AC sensors. When leaded gas has been used, even the Densos will show a sluggish cross count, but, will sometimes clean back up with use. Watch the counts, if they don't recover to a normal level, put another one in if you want optimum mileage and part throttle performance.
If you have a chip that provides an Open Loop idle, it will probably show zero cross counts at idle and this is normal. Check the cross counts at cruise. Also, do not expect cross counts at wide open throttle.

 

[earlbrown]

They were Bosch....

You found your issue. Those things will get lazy at the drop of a hat.


AND they'll drop the hat.