TAQuickness
January 27th, 2006, 02:40 AM
:help2:
Most every time I'm returning to an idle state, the PCM makes the transistion gracefully. On occasion, the PCM makes the transition rapidly and stalls the engine.
Last night I captured a log, while the car was stationary, that shows the throtle follower does not decay consistantly. Per the tune settings, when the follower has added 3.0 g/s, it should take ~ 7.6 seconds to decay to 0 g/s.
The attached file contains a log and a spreadsheet (I know, I know). Within both are 2 idle transitions of interest (more easily viewed in the spreadsheet).
Transition 1: Goes from idle, to ~2k RPM where the follower adds 3.0 g/s additional air flow, the follower decay takes 7.6 seconds to return to 0. THIS IS THE DESIRED EFFECT!
Transition 2: Goes from idle, to ~2k RPM where the follower adds 3.0 g/s additional air flow, the follower decay takes 1.5 seconds to return to 0, resulting in the engine stalling. THIS SUCKS!
So, my question is, what variables effect the decay rate of the throttle follower?
Ross - can you shed any light on the PCM formula behind the throttle follower decay rate?
:cheers:
Most every time I'm returning to an idle state, the PCM makes the transistion gracefully. On occasion, the PCM makes the transition rapidly and stalls the engine.
Last night I captured a log, while the car was stationary, that shows the throtle follower does not decay consistantly. Per the tune settings, when the follower has added 3.0 g/s, it should take ~ 7.6 seconds to decay to 0 g/s.
The attached file contains a log and a spreadsheet (I know, I know). Within both are 2 idle transitions of interest (more easily viewed in the spreadsheet).
Transition 1: Goes from idle, to ~2k RPM where the follower adds 3.0 g/s additional air flow, the follower decay takes 7.6 seconds to return to 0. THIS IS THE DESIRED EFFECT!
Transition 2: Goes from idle, to ~2k RPM where the follower adds 3.0 g/s additional air flow, the follower decay takes 1.5 seconds to return to 0, resulting in the engine stalling. THIS SUCKS!
So, my question is, what variables effect the decay rate of the throttle follower?
Ross - can you shed any light on the PCM formula behind the throttle follower decay rate?
:cheers: