Here not too long ago I installed a CC503 cam and it cranked fine and runs fine in the upper rpms but down low I have a surge issue almost like a miss. When I described the problem in a earlier thread someone mentioned cam surge. So I started looking up cam surges and that sounds just like my issue. But the more I drive it the more I fill that this little cam can’t be this bad. I started to look up stuttering and so a lot of folks mentioned O2 sensors. Well I know I haven’t replaced mine in 8 years so tonight I unplugged them and drove the car and I didn’t have any more stuttering at all it was all smooth. My question is when disconnecting the O2 sensors what all does that do? Do you think my O2's are shot? Here is a link to the post that i started about the surge when i installed the cam. http://web.camaross.com/forums/showthread.php?t=631681
Thanks in advance sorry for the long post

 

when you unplug them it goes into closed loop. so yes i'd say thats your problem.


does it drive fine cold and then surges when its warmed up a bit?

 

Thats exactly what it does. Drives fine until it warms up. So when it goes into closed loop it bypasses the O2 sensors only?

 

Just for clarification.
Open loop bypasses the O2's and runs off the learned cells stored in the PCM. Cold motor
Closed loop uses the O2's to adjust A/F on the fly. Hot motor

 

I am going to do a data scan tonight and post it up. Hope fully can tell me if anything is wrong. I just dont fill that this is normal for this cam.

 

Can someone take a look at this and tell me if they see a problem?
http://gh94z28.diinoweb.com/files/
It is the 092208.csv file. Thanks

 

just change the o2's

o2's aren't read at WOT or open loop, you found the problem

 

This is what someone else told me. Can you look at my data log that i posted and see if it is my O2s?

Basically by unplugging the o2's, your pcm switches back to open loop. The pcm in open loop commands more fuel at low rpms/idle. This is why you have no surge in open loop. When the pcm switches to closed loop, it uses the o2 sensors to maintain stoich 14.7:1 afr. This is sometimes to lean for some cams and causes surge. It also can be a exhaust leak lettin air enter the exhaust, which hinders the o2's readings, which will cause surge. A hands on tune might eliminate most of the surge, being there are no exhaust leaks.