Hey Yall... Since I rebuilt this 1994 3.4 SFI motor I have been trying to tune it so that everything is within spec but have run in to a couple issues that are puzzling me and I am hoping one of you will be able to offer up sugegstions on what is causing this weird O2 reading on the left O2.

The motor is a 3.4 v6 from a camero and the ecm I have is a 16172693. I also have but have not tried a second ecm I have which is a 16196397

So when I got this rig there was no check engine light wired up off the ecm nor was there an ODB1 port wired up. Both of those are done now so that I can see whats going on with the motor. The only codes being thrown are trans codes due to the fact I'm not running the 4L60E stock trans that the ecm was programmed for.

None the less have a look at the video below and pay attention to the O2 sensor Mv readings. From what I know your O2s should swing voltage from 0 to a peek of about 900 Mv. You can see the right O2 is reacting as it should but the left O2 is not. You can see the differences in the video at idle and through some higher RPMs....

Through the process of elimination I have swapped the O2 sensors from side to side and the left still reacts the same so it is not the sensor itself.

I'm thinking along the lines I have a plugged or a leaky injector on one or more of the left side injectors. The low Mv readings indicate a rich situation on the left side... As far as I know.

Thoughts? Ideas? I could really use some input on this from you EFI guys.

Thanks in advance!

Here is a second video showing all of the results in my scanner. Should give you a better idea as to what is going on?



Hope you guys can help out, no luck with people on other forums.