hello

so my car was tuned by a professional tuner , however, I am facing problem with partial throttle between 1800rpm and 2000rpm , the cars goes very lean 18+AFR and chocks as if its going to stall(at any load level and any gear ) ,as the rpm pass 2000rpm every thing is back to normal it even records 5 degree on knock on that area , other than that no issues with boost or anything else

I went to the rom and added fuel on between 1750 - 2000 rpm and that solved the problem , however, I think that's not the best way to do it , I want to know the reason y it happens in the first place

2009 evox
ams intercooler and upper lower pipes
fpgreen turbo
1000cc injectors
ams fuel rail
fuel regulator
myth injection
stock cams

attached snap shot of my fuel and timing maps

 

Did they change the MIVEC maps and not add fuel to compensate? Aggressive MIVEC can cause leaning.

In any case, you did the right thing if it was running lean.

Thanks!
verkion

 

if you're showing lean, and adding fuel was the fix...I'd say you already found the problem. It was probably just an oversight by the tuner. On the street, a car can get into different load values than a dyno. There's always areas of a map that are calculated and can be off.

 

Look at your maf tables to see if there's any kind og dramatic variances in that rpm range. If not you're on the right track. On a side note, I'd be curious to see a log of your timing durring a pull.

 

thanks you all for the replay

I am just wondering why the car goes very lean (5 knock )on that RPM range while its fine before and after this range the AFR matches what I have on my map ? could it be bad MAF,o2 or Air leak ?

on the below link , I have attached my ROM can you please take a look at it and tell me if you can find a reason for this problem , and maybe post a replay on that other thread ?

https://www.evolutionm.net/forums/ev...l#post10961139

attached few pics of my car , we call it RS in Saudi No ABS no Traction it has no options at all ,mechanical transfer case and diffs ,do u guys have it in the state ?