Nissan 370Z Forum - View Single Post

wstar · 10-04-2011, 12:57 PM

Ok, so I did my crazy extreme map testing. I need to sit down and think through the results, but they should be informative.

Based on my smooth map from the top post, crazy map #1 was altered so that all of the columns from 37.5% flow onwards (to 100) were all pegged to the value "3800". The result from a driving perspective is that when I reached somewhere around 1/3 gas pedal position, the car would suddenly jump like I nailed the pedal to the floor, the OBD-II throttle position values would jump out to high values (wide open), but the whole jump would be very brief. Basically if I held onto that pedal position, the car would pulse on the throttle between 1/3 and full. It was like it was trying to take off at full throttle, but something else in the ECU held it back a short moment later.

Crazy map #2 was the opposite. From the 37.5% column onwards, all values were pegged to the number "1310". The reaction was somewhat similar. At around 1/3 throttle, the car would suddenly jump in power like I tried to nail the gas hard. However, the OBD-II throttle position sensor would *not* jump to wide open when this happened, just the engine power surged, and power got retarded back pretty quickly like the previous test, although smoother.

I imagine all the throttle jumping around and acting retarded in both scenarios is because there are other tables involved (e.g. VVEL) and the ECU in the overall is either confused by or just flat refuses to follow the contradictory commands with crazy values. But it does seem to confirm that raising the numbers in the table leads the ECU to at least try to open the throttle wider.

I need to think more on all of this to make sense of it though.

10-04-2011, 12:57 PM	#13 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Ok, so I did my crazy extreme map testing. I need to sit down and think through the results, but they should be informative. Based on my smooth map from the top post, crazy map #1 was altered so that all of the columns from 37.5% flow onwards (to 100) were all pegged to the value "3800". The result from a driving perspective is that when I reached somewhere around 1/3 gas pedal position, the car would suddenly jump like I nailed the pedal to the floor, the OBD-II throttle position values would jump out to high values (wide open), but the whole jump would be very brief. Basically if I held onto that pedal position, the car would pulse on the throttle between 1/3 and full. It was like it was trying to take off at full throttle, but something else in the ECU held it back a short moment later. Crazy map #2 was the opposite. From the 37.5% column onwards, all values were pegged to the number "1310". The reaction was somewhat similar. At around 1/3 throttle, the car would suddenly jump in power like I tried to nail the gas hard. However, the OBD-II throttle position sensor would not jump to wide open when this happened, just the engine power surged, and power got retarded back pretty quickly like the previous test, although smoother. I imagine all the throttle jumping around and acting retarded in both scenarios is because there are other tables involved (e.g. VVEL) and the ECU in the overall is either confused by or just flat refuses to follow the contradictory commands with crazy values. But it does seem to confirm that raising the numbers in the table leads the ECU to at least try to open the throttle wider. I need to think more on all of this to make sense of it though. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 10-04-2011 at 01:07 PM.