ok guys i got this prob with my car when im tuning, the tune changes with the weather!! WTF? we tuned my car a few weeks ago and then afrs changed (swung rich)the next day! so my mate retuned straight away and it was fine and then changed again the next day. fuel pressure would change on idle so i thought it was fuel related....i swapped out everything put in surge tank, ext pump afpr and fuel pressure was steady, great yeh? so yesterday was 35 degrees cel and we tried tuning it....we had a hard time scaling the injs and making power, it would make power then it was like it got hot and started to lean out, we tuned the car like 3-4 times in an hour cos it kept changing went leaner and leaner, we ended up scalling 1650s to like 8xx....so we gave up for a couple of hours. after the car cooled and the weather cooled down to 28deg cel, we decided to take it out again for a drive and tuned up great! made like 490hp mustang vdr..... but then just sitting on the side of the road on idle my mate was fine tuning the map, the idle just dropped and everything changed! run leaner! from 11.8 it jumped to 13s......would anyone have a clue about this?

 

anyone have any thoughts?

 

Don't touch your injector settings. Scale them to within spec ie +/- 3-5% fuel trims. And leave them.

Make sure your maf is scaled properly and is clean.

Make sure that there is not a vacuum leak near the FPR. Ziptie all vacuum lines.

I don't know if evo vi came with the lean spool option , if it did turn it off completely (peripheries)

boost leaks, etc,etc

If you cannot figure it out, take it to a pro tuner to see if they can find the root problem.

Good luck man

 

turns out it was the injectors! as the fuel heated up the injectors would reduce flow....they were the bosch 1600 hi-z

 

Glad you figured it out man

I have never heard of that before.