I don't even know how to describe this properly. Basically, I hooked up an OBD2 reader to my RX8, exported the data and graphed it.
This is my RX8 at a fixed throttle position at 1800rpm (ignore the value after 100K ms).
This is a graph of the idle values at rougly 800rpm.
The K values stand for the amount of seconds (20K ms = 20 seconds).
Notice how in the graph of 800rpm, the Short Term Fuel Trim jumps up and down radically.
I did some calculation, and it seems from this data that the MAF is the first to pick up a specific signal, to which the Trim values and O2 values follow. 1I stands for 1st interval Increase, and 1D stands for 1st interval Decrease. The values after are the miliseconds. when the increase or decrease in values occur.
From this dataset I can conclude that the MAF is the first to pick up a change. The deviation betweens these interval values is so small and precise, that it suggests it's some signal causing this disturbance in MAF readings, or any other sensor connected to the ECU. A vacuum leak should be steady, and any malfunction like a dirty sensor or a misfire causing the sway in RPM and whatnot should be give irregular random values.
Some time before this, I have noticed that when the radiator fan turned itself on during idle, the short term fuel trims would drop, until the radiator turned off and they rose again. I will check this out tomorrow, and if this turns out to be related, it either means that a) the fan blows against something that causes the values to change (movement of air), or b) the electrical current of the fans affects the voltage of the MAF sensor cable. It probably doesn't make any sense, but it's the only think that I can think of.
Last weekend I have been moving around with my airbox, looking for a vacuum leak while my engine was running before I have found out about this data. When I moved the Airbox in a specific way, the LTFT and STFT would go towards 0% pretty rapidly, and it came back when I stopped fiddling. It was still attached to the airduct.
I have noticed something similar a year ago, when my radio would cut off for roughly 500ms. I decided to measure the interval, and it happened every 6 or 60 seconds, with a deviation of roughly 300ms (in which my thumb was the major factor).
So my actual question is, what can cause the interval in MAF readings? It works pretty much like connecting the MAF to an indicator light and turning it on. Is there something in a 2004 RX-8 Renesis HP which works according to 7-14 second intervals?
This is my RX8 at a fixed throttle position at 1800rpm (ignore the value after 100K ms).
This is a graph of the idle values at rougly 800rpm.
The K values stand for the amount of seconds (20K ms = 20 seconds).
Notice how in the graph of 800rpm, the Short Term Fuel Trim jumps up and down radically.
I did some calculation, and it seems from this data that the MAF is the first to pick up a specific signal, to which the Trim values and O2 values follow. 1I stands for 1st interval Increase, and 1D stands for 1st interval Decrease. The values after are the miliseconds. when the increase or decrease in values occur.
From this dataset I can conclude that the MAF is the first to pick up a change. The deviation betweens these interval values is so small and precise, that it suggests it's some signal causing this disturbance in MAF readings, or any other sensor connected to the ECU. A vacuum leak should be steady, and any malfunction like a dirty sensor or a misfire causing the sway in RPM and whatnot should be give irregular random values.
Some time before this, I have noticed that when the radiator fan turned itself on during idle, the short term fuel trims would drop, until the radiator turned off and they rose again. I will check this out tomorrow, and if this turns out to be related, it either means that a) the fan blows against something that causes the values to change (movement of air), or b) the electrical current of the fans affects the voltage of the MAF sensor cable. It probably doesn't make any sense, but it's the only think that I can think of.
Last weekend I have been moving around with my airbox, looking for a vacuum leak while my engine was running before I have found out about this data. When I moved the Airbox in a specific way, the LTFT and STFT would go towards 0% pretty rapidly, and it came back when I stopped fiddling. It was still attached to the airduct.
I have noticed something similar a year ago, when my radio would cut off for roughly 500ms. I decided to measure the interval, and it happened every 6 or 60 seconds, with a deviation of roughly 300ms (in which my thumb was the major factor).
So my actual question is, what can cause the interval in MAF readings? It works pretty much like connecting the MAF to an indicator light and turning it on. Is there something in a 2004 RX-8 Renesis HP which works according to 7-14 second intervals?
MAF Values show 7-14 seconds interval. What functions according to these intervals?
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