I have a basic d16 build, I started street tuning it a few nights ago. Had it pretty well dialed in to 14.5 while driving and 12.5 under light boost. So the next morning comes, start driving, I see my AFRs go into Hi 14's and low 15's. So i started goofing around did some more street tuning got the afrs to where i like them. Took it out later that night/morning so insted of hi 70 degrees out it is low 50's and the afr's while driving were into the 12's now.. I have never had weather mess with my tune this bad. I have always used s200 so some s300 things are new. Anyone and any insite for me?? I apperciate!
I also have a PLXm300 I use ALOT, been using it almost every day minus a couple month for winter. got back in 06.. so i dont know if the sensor is screwing with me..
night and day problems
Before you go messing with the temperature corrections do yourself a favor. Take a look at your battery voltage with the headlights on, then off, and with the fans on and off etc..
I had the same problem as you. I tuned at night and in the day it would run lean. I tuned in the day and it would run rich at night, but my iat stayed the same (FL summer and bad intake placement).
What I found was actually happening was the injector battery offsets were wrong.
The more power you put to an injector the faster it will open and therefore the longer it will stay open for a given pulse..which will make the car rich.
I didnt think this was the problem because my logic told me that the light and everything being on would draw power and lower voltage. But what was really happening was when I hit the lights the alternator would kick on to compensate for the load and actually increased the voltage, making my car run richer. It took me 15 secs to look at the change and adjust the injector dead time at the right voltage to get the car right. Now it idles and runs within .5 afr day or night.
I had the same problem as you. I tuned at night and in the day it would run lean. I tuned in the day and it would run rich at night, but my iat stayed the same (FL summer and bad intake placement).
What I found was actually happening was the injector battery offsets were wrong.
The more power you put to an injector the faster it will open and therefore the longer it will stay open for a given pulse..which will make the car rich.
I didnt think this was the problem because my logic told me that the light and everything being on would draw power and lower voltage. But what was really happening was when I hit the lights the alternator would kick on to compensate for the load and actually increased the voltage, making my car run richer. It took me 15 secs to look at the change and adjust the injector dead time at the right voltage to get the car right. Now it idles and runs within .5 afr day or night.