Tq Red. Throttle Closing DFCO

[Thatwhite5.0]

DFCO High RPM Torque Reduction
I've seen a few questions about people trying to find out why their throttle body is closing after a shift. This may fix your problem, or it could be another form of limiter or torque reduction. You floor it, shift gears fairly fast, push the pedal to the floor, and your throttle angle opens to 82 degrees, then decreases to less than half of that, then it opens back to max angle. I started randomly experiencing torque reduction shifting to third or fourth gear that would close the throttle body and lean out and resulted in the following sources.
Throttle Angle Source TQ Red. < Driver Demand
Torque Source Traction Control
Driver Demand Limit Source No Limit Active

Torque Reduction < Driver Demand was causing the throttle angle to decrease from 82* down to 30*. My Torque Request decreased from 450 ft lbs to 210 ft lbs. Traction control at 110 MPH, I?m not sure why I was getting that source on a Naturally Aspirated car, but what I done got rid of that also.

throttlepic1.JPG

After studying my log a little more, I also noticed my commanded lambda was a lean target and using the table in Engine > Fuel > Open Loop/Base > Torque Reduction > [44517] Fuel Cyl Cutoff. I was told a long time ago to keep this table stock, I obviously wanted to richen up the higher loads because it sounded right but was advised not to. I?d like to hear opinions on [44517] Fuel Cyl Cut off targeting 1.2 lambda at 100% load, all RPM.

fuelcuttable1.JPG

I still have fuel cutoff table stock. This is the DFCO section.

DFCO1.JPG

This section is full of thresholds. Each threshold is a possibility to enable or disable Deceleration Fuel Cut Off.
Enable RPM - You MIGHT have fuel cut above this RPM.
Disable RPM - You will not have fuel cut below this RPM
Enable VSS ? You might go into fuel cut above this vehicle speed.
Disable VSS ? You will not have fuel cut under this vehicle speed.
Disable Load ? Any time you?re under 100% load, you MIGHT enable DFCO . This is where my problem was at. Stock is set to disable ABOVE 1.0 load, 100% load. Even after an 8000 RPM shift like in the screen shot, and actually into the next gear WOT can experience fuel cut. Any time I am decelerating, my load drops very low. I changed Disable Load from 1.0, to a new value of .4. I could of chose a lower load like 15% but I wanted some benefit of saving fuel at highway speeds and highway loads. 70mph, 35% load decelerating down a hill will cut the fuel.
Disable N/V ? This is a ratio of your RPM divided by your MPH. I changed this value from a factory 0 to 35.00. That is not in MPH. 2200 RPM divided by 70 MPH, N/V Ratio is 31. 7000 RPM divided by 30 MPH is 233.
Ramp On Rate and Ramp Off Rate. I?m not sure what units these two use, I didn?t notice a major difference set at stock, or set to max values.
Closed Throttle Delay and Delay Extended. Honestly I haven?t touched these.

Like I said, this is just one fix for the throttle body closing. You may be experiencing the same thing but a different table needs changed. My torque reduction had my traction control light flashing on my cluster at 110 MPH.

Backfiring and popping exhaust on deceleration. Yes, DFCO is the section to change. I still try and get decent MPG, but only on the highway.
Enable RPM ? 1400
Disable rpm -1100
Enable MPH - 55 MPH
Disable MPH - 50 MPH

?But you were at 110 MPH during fuel cut, why are you enabling it at 55 MPH.? All thresholds will not be met during a WOT shift.
You will have popping out of your exhaust during deceleration driving 25 MPH at 5000 RPM with the Enable DFCO RPM set to 1400.
The Enable VS set to 55 MPH which "cancels" the other threshold out. The Disable NV Ratio is set to 30. 5000RPM divided by 25MPH is NV Ratio of 200. 6000 RPM divided by 110 MPH is an NV Ratio of 55. The conditions have to right, mine were just right for torque reduction.

Here's a small spread sheet that should cover most cruising and highway NV ratios up to 8000 RPM.
nvratiosheet.JPG

[engineermike]

Thatwhite5.0 thanks for posting this. I'm having a similar issue but it's not going lean. I get a torque source of traction control at 105-110 mph even with TC off and no sign of tire spin. I saw elsewhere that if you exceed a transmission element rpm limit then it will also cut torque and show a torque source of "traction control". Any idea why these various and seemingly unrelated throttle cuts show "traction control" as the torque source?