Does anyone here have experience with the DFCO constants?

I've been having a bizarre problem lately, and I don't remember changing anything in DFCO that would have caused it.

DFCO is staying enabled even though according to the constants I have set, it should be disabled.

For example, I have the DFCO MPH Enable table set to 20mph. This means that DFCO only works when the car is above 20mph, correct? Well, it is still enabled even down to a stop (0mph).

This has the effect of me idling at 0* advance. If I blip the throttle when this happens, it will go back to normal, back to the closed TPS advance value.

Has anyone seen this happen? Any ideas why it's happening? If you need to know more or want to see log files, let me know!

 

No, it means it is enabled once you reach 20 mph. For disabling you have to look at the various parameters which are labeled, coincidentally, "disable."

If you need info on DFCO I suggest searching on impalassforum. Most of the threads I've seen on the subject have been over there.

 

IDK about LT1s....but on LS1s, you have a MAP enabler/disabler trigger. You don't want the idle kPa lower than the DFCO disabler. For example, mine idles with the MAP at 55~60kPa. I have DFCO to enable if MAP is below 33kPa and it will turn off when MAP hits 40kPa. Another trigger is RPM. Mine has to be above 1600RPM for it to turn on and will turn off at 1200RPM if the MAP trigger hasn't already disabled it. There's also a TP% ceiling per RPM that I pretty much left stock.

 

OK, so the MPH setting works slightly different than I expected, but my other settings should still be disabling it, it would seem.

The RPM Disable Threshold is set to 1300 RPM. My idle is about 950 RPM. Yet when coming to a stop, DFCO will still be enabled even after the RPMs go under 1300. Even to my idle RPM and below (because with ~0* advance, the RPMs dip into the 600-700s).

Here are my settings in TC on my '95; can someone tell me if they see the problem?

Enable RPM Threshold: 1400 RPM
Disable RPM Threshold: 1300 RPM
Enable MAP Threshold: 38kpa (have tried higher and lower settings)
Disable MAP Threshold: 50kpa (have also tried lower settings)
Disable RPM Decrease Threshold: 2500 RPM/sec
Enable Coolant Temp. Threshold: 29.75C
Enable MPH Threshold: 20mph (have also tried 15 and even 10 in the past and it seemed to work fine)
Enable Delay Timer: 0.5 sec
Spark Retard: 25* (have also tried 20-23)

My closed TPS advance:

400 RPM: 18*
800 RPM: 24*
1200 RPM: 30*

My requested idle at operating temps: 925 RPM

My usual idle vaccum: 55-60kpa

Any more ideas? From the logs, DFCO is obviously staying on all the way to a stop and continues at idle. What should I try adjusting?

Thanks again for the input!