Throttle follower

[5.7ute]

Decided to go for a spin tonight & log follower & cracker to see what air is added when. Throttle cracker logged no extra air but follower continually added air in increments ranging from 6 grams to 2 grams. This continued up to 63 grams where it started again from zero. The throttle follower decay tables are untouched from standard.
Any ideas???

[TAQuickness]

are they giving your problems?

I've noticed my TC PID has a value of 0 any time i'm in second gear, but I have reason to believe the PCM is adding the TC air in 2nd. I haven't seen anything like you describe on the TF though.

[SSpdDmon]

You say the decay rates are untouched. What are they? Post tune please... :)

[5.7ute]

are they giving your problems?

I've noticed my TC PID has a value of 0 any time i'm in second gear, but I have reason to believe the PCM is adding the TC air in 2nd. I haven't seen anything like you describe on the TF though.
I have been trying to track down a tendency for the car to act like cruise is enabled. After much searching the cracker,follower seemed like the best place to start looking. DFCO is active.

[Tordne]

Cruise control can also be that the Desired Airflow table has not been tuned to be accurate. One thing (and this is a bold call) that the stock tunes seem to do is be a little lazy with some of the airflow related tables because they are expecting there to be a MAF to mop up after them. Speed Density on these is a failed condition and you are supposed to drive straight to the service center to get a new MAF :)

[5.7ute]

I had reconnected the maf previously to try & get that dialled in but that made it worse. Trying to keep under the speed limit was near impossible as the car tended to creep up in speed with near no throttle. In the end i decided to leave it in SD until I could sort out the few drivability issues it has.

[TAQuickness]

From what you're describing, it sounds like the cracker is putting too much air in. Took me a long time to find a happy place in the sub 25mph range.

[5.7ute]

That was what I thought but in the log cracker isnt showing any airflow. Unless it shows up in the total of follower & not in its own pid.

[5.7ute]

Does the iac valve control follower & cracker airflow? I have done another log with the iac steps logged as well as follower & cracker. Again follower goes up to 63 in increments & then starts at zero. The iac shows to be stepping up & down but having no effect on follower airflow on the chart. Is this a cumulative chart or should it read with follower demand ? This log is 10000 frames & shows it quite clearly stepping up until it restarts at around frame 4500. I am not sure if I am chasing a problem or not so any help will be appreciated.

[TAQuickness]

IAC is responsible for DAF, TC, TF, SU, SUF, and probably one more I'm not thinking of... It controlls all air flow not directly controlled by your gas pedal.

If you are logging VSS and RPM (with matching units to the tune tool), from the scan tool chart view (Dashboard Tab), you can select the data in your log that is giving you a problem.

In the tune tool, the corresponding cells in your calibration should be highlighted as well (automagically - if not let us know).

Select the highlighted cells and reduce them by small increments (2%-5% at a time), then go for a test drive. We start by reducing the calibrated values because you've described the throtle is hanging.

This is basically a wash, rinse, repeat procedure. Took me about 4 or 5 drive cycles to get my low speed drivability back.

[5.7ute]

I understand the method to tune the various airflows in. What I dont understand is how the cracker pid is not showing any airflow, when it is causing the throttle hang. Yet the follower pid is showing a continual raise in airflow until it maxes out then starts again.

[5.7ute]

OK I have followed advice & have made a few changes.
I have changed all my cracker , follower tables & have copied the GTS ones as they run mafless & would be a better starting point, however this invoked a stalling problem as idle was not held under control. This I put down to the desired air table so I also copied this from the same tune file as a starting point.
This has rectified the stalling issue & now the car is close to where I want it but there is still a few issues that remain unresolved.
When I try to log rafig it always comes up at zero.
The log of throttle follower is always a constant increase until it becomes out of range & has no relation to the iac position.
Am I understanding the relationships of these pids wrong or is there an issue that I am unaware of ?

[Tordne]

If you are at idle and all the after start and friction airflow has decayed out the Throttle Follower values should go to 0 (if i remember correctly - been a while since i really looked at this).

Desired airflow is the base airflow table.

Throttle Follower as you can see from the table is an added airflow above a certain TP% change for a given TP%, affected by an RPM multiplier.

Throttle Cracker is added airflow for a RPM vs. Speed and is basically active all the time (above 3km/h and disables below 1.6km/h stock GTS values).

The IAC motor is simply a means of allowing for this extra airflow to pass through the throttle body.