DFCO Timer

[myfast70]

What is DFCO? I'm new to the forum and am trying to learn as much as I can before I take the leap.

[2002_z28_six_speed]

2001 F-body M6
OS: 12202088
B3307 is set to 0.00

Is there a reason why it still takes 2 seconds for my DFCO to activate? When I let off in 3rd gear at say 3500rpm, it meets the TPS, RPM, MAP, and MPH requirements to enable DFCO. But, it still doesn't kick on for 2 seconds even with B3307 set to zero.

I have the same issue. COS5 or 2002 M6 OS. Never comes on immediatley.
Is it possible the PCM doesn't poll the requirements to enter DFCO fast enough?

[SSpdDmon]

What is DFCO? I'm new to the forum and am trying to learn as much as I can before I take the leap.

Decel. Fuel Cut Off

I have the same issue. COS5 or 2002 M6 OS. Never comes on immediatley.
Is it possible the PCM doesn't poll the requirements to enter DFCO fast enough?

At least I know I'm not going crazy. I don't think it's a 'slow poll' issue. I think it's the OS. My buddies '99 used to enter DFCO immediately. After I upgraded his OS to get to one VE table, his car doesn't do it anymore.

[Haans249]

Has anyone found anything out from this? I'm working on DFCO as well, and I also notice the 2 second delay when entering once all parameters are met. I would like it to enter DFCO instantly once I'm off the throttle and still in gear. I'm going to try setting the timer to .05 and see if its set to 0 if it will default to 2 seconds.

[WeathermanShawn]

2002 M6 here, does the same thing. Like SSpdDmon said, I think there are more functions either 'hard-wired' or tables not available than we know. I'm sure it is somewhat of an 'engine protection' feature. May not be wise to immediately cut off injector flow instantaneously.

I do not like my DFCO settings to be overly 'trigger-happy' to engage at every throttle letdown. Let us know if you can figure it out.

[Haans249]

2002 M6 here, does the same thing.

Like SSpdDmon said, I think there are more functions either 'hard-wired' or tables not available than we know.

For me it is not an issue. I'm sure it is somewhat of an 'engine protection' feature. May not be wise to immediately cut off injector flow instantaneously.

But, that is total speculation. May be unique to our operating system.

Personally I do not want my DFCO settings to be as 'trigger-happy' to engage at throttle letdown. But, let us know if you can figure it out.

Regards.

..WeathermanShawn..

I will let you know. I want mine "trigger-happy" because if I let off the throttle while still in gear, its because I want to slow down haha. I have my parameters set that DFCO will turn on ONLY when I'm downshifting to slow down (coming to a light, slowing down on highway etccc) without having to hit the brakes. If I want to coast, I'll just push the clutch in :nod:

[dfe1]

Take a look at Spark>DFCO. I've found that delays in entering DFCO once all parameters are met are usually the result of spark ramp rate. DFCO won't be activated until timing is reduced to the trigger value (in B3336). If the Ramp In rate is too slow, you'll have a noticeable delay. Change the values in B3334 and you should notice a big difference. Also note that once in DFCO, timing will be reduced to the value in B5915 under most circumstances. I have the values in B3334 at .04 and DFCO activation is almost immediate when I get off the throttle. Higher values obviously activate DFCO more quickly, but may make activation too harsh.

[Haans249]

Thanks for the input! I will try that tomorrow. I put the delay to .05, but didn't notice a difference. I already have the values in B3334 set to .1, but I will put it at .6 to see if there is any difference. I also already have the values in B5915 set to 0 as well.