Unusual TPSdot event
Posted: Fri Nov 20, 2015 3:14 pm
I don't know whether this is a tuning / configuration issue or a software or firmware issue; but, I am going to start with tuning / configuration.
I was doing a datalog during a start and warm-up as part of tuning my start-up parameters. While scrolling through the datalog, I came across this oddity. The engine is at idle; but, the TPS must have vibrated slightly or picked up an errant signal somehow which registered as a brief drop in throttle position from -0.3 to -0.6 % (green line - top trace). What is confusing is that the drop in throttle position registers as a + TPSdot (yellow line - top trace). I have seen these small TPS transitions before and negative transitions have always registered as a - TPSdot. In this particular case, the TPSdot value was above my threshold value of 20% and triggered accel enrichment (red line - top trace). This appropriately resulted in an increase in PW (red line - bottom trace); but, there does not appear to be any attendant disturbance in the AFR signal (yellow line - bottom trace).
My primary question is, what could cause the positive TPSdot in response to a negative throttle transition? As a secondary issue, any thoughts on why the change in PW did not show up as a disturbance in the AFR? The PW changed from 5.5 to 7.2 for approximately 0.3 seconds which is not insignificant and should have shown up in the AFR.
I have the full log available if someone is bored and wants to peruse.
I was doing a datalog during a start and warm-up as part of tuning my start-up parameters. While scrolling through the datalog, I came across this oddity. The engine is at idle; but, the TPS must have vibrated slightly or picked up an errant signal somehow which registered as a brief drop in throttle position from -0.3 to -0.6 % (green line - top trace). What is confusing is that the drop in throttle position registers as a + TPSdot (yellow line - top trace). I have seen these small TPS transitions before and negative transitions have always registered as a - TPSdot. In this particular case, the TPSdot value was above my threshold value of 20% and triggered accel enrichment (red line - top trace). This appropriately resulted in an increase in PW (red line - bottom trace); but, there does not appear to be any attendant disturbance in the AFR signal (yellow line - bottom trace).
My primary question is, what could cause the positive TPSdot in response to a negative throttle transition? As a secondary issue, any thoughts on why the change in PW did not show up as a disturbance in the AFR? The PW changed from 5.5 to 7.2 for approximately 0.3 seconds which is not insignificant and should have shown up in the AFR.
I have the full log available if someone is bored and wants to peruse.
