7427 $0D Not Going Into Closed Loop

[Thainglo]

Been scratching my head on this for awhile, finally thought I would pose my issue to this group for some assistance. I have a TBI system installed on a 78 Corvette, powered by a 16197427 PCM. Been running great the last few years. Past couple months, I noticed some serious stumbling once the car heated up. Turned out my coil had come loose from its riveted mount and was causing lots of problems. Swapping in a good used coil made it run 10x better.

I had it hooked into TunerPro and noticed it was not entering closed loop. Sometimes the flag would turn very briefly to Closed, then the next moment back to Open. I watched the oxygen sensor readout and it looked really, really slow. Knowing that the PCM was looking for an O2 reading as part of the parameters to enter Closed Loop, I purchased another (Bosch 13077) and installed today. Took it on a 10 minute test drive and it still did not enter Closed Loop.

Can anyone list the parameters for closed loop operation? I know that Coolant Temp must be at a certain threshold and run time. Is there something I'm missing?

Attached is the current .bin file that the car is using, I'd greatly appreciate any comments and thoughts.

Thanks!

[Thainglo]

I should also add that the coolant temperature reading in TunerPro is spot on, around 200 degrees when at operating temp. Also, there is no check engine light being lit.

[sturgillbd]

You also need O2 switching. Look at your O2 sensor data. I'll have to view your bin to see what your calibration is like

Brian

[Thainglo]

You also need O2 switching. Look at your O2 sensor data. I'll have to view your bin to see what your calibration is like

Brian

Agreed. I was reading back thru the pdf manual from years ago, oxygen sensor cross counts, or something to that effect. Will fire up the car and check it out. Thanks!

[Thainglo]

Finally was able to get in the car long enough to record a log while driving. Hopefully I'm attaching it correctly? This is with a new oxygen sensor (Bosch 13077). I'm concerned that while holding at steady speed (approximately 40mph), the O2 reading is flat. Might be totally normal? I watched the O2 cross counts, that seemed ok, but again stayed flat for coasting sections. Any guidance much appreciated.

[stew86MCSS396]

Your "Closed Loop Idle" is checked. When I use "compare" to other bins, it is not checked. Your House Run xdl, closed loop flashes for a fraction of a second and purdy much stays open loop the entire log. I'm a little concerned that the log appears glitchy with alot of data swings???