hi guys this is my first post and i need your help! (great site!)
my 94z28 6spd felt a bit slow,no SES light,it just seemed to struggle finally got it scanned,nothing showed up,but my o2 sensor readings were 8mv to 800mv really quick,is that normal?
thanks for your help
i live in england so its hard to get help or advice with these cars

thanks

andy

 

Perfectly normal.

 

In closed loop, the O2 sensor readings will swing repeatedly back and forth between 0xx - 9xx mV. They actually change faster than you can monitor, about 9 times per second. That's the nature of closed loop control. The PCM reads the O2 sensors as "lean" and overcorrects to "rich". The O2's go "rich" and the PCM overcorrects to "lean". This is required to allow the cats to process the pollutants in the exhaust, some of which (HC and CO) require excess oxygen to be converted to harmess CO2 and water, and one of which (NOx) requires reduction to free the nitrogen from the oxygen.

If you want a brief summary of the A/F ratio control system, and what it's going to look like on a scannere, try my online guide:

http://members.aol.com/InjuneerZZ/ScanMast.htm

 

turbo z and injuneer thanks guys!
i really thought it was my o2s?,i did have the SES light come on 2 weeks ago,and my car was scanned it was the EGR,which was disconnected,and he plugged up where it goes to the inlet,the ses light went afterthat?
do you think i should take off the whole EGR?

THANKS AGAIN

 

I had my EGR disconnected and capped and don't know how the hell it got that way. It was affecting my cooling fans somehow. WIERD, no garage has ever worked on my car except for the air pump recall. Must've been them