Hi..I have an issue here and need help..my evo 7 ..use ron 97 ..cp piston 86.5mm ..eagle con rod..stroker 2.4...using fuel pump DW380 with additional fuel pum relay.
ECU Flash . After few run... my afr shows lean in sudden during In 3rd gear and some time in 2nd gear ..accelerate at 9.8 to 10.1 Afr comes to full boost at 6k to 7.3k rpm, afr shows lean at 13.4 and car sudden bang boom jerking..its always happened when I pull hard to accelerate. .
I've checked
1- Fuel pump hosses and o ring..result ok with pressure max 7 bar
2- Fuel regulator. .trying to changed new..
3- New injector ID 1000cc and log the duty cycle show utilisation is max 76% at 7.3k rpm
4- Re map at dyno. .
5- New plug iridium

Any other things? ..some mechanic says is my o2 going to death..but I'm doubt because there is no check light.
Those can help, I don't mind to share my bin file for you to determine and advis . .is there any function in my flash are wrong either in fuel map or other folder...drop me your email address and I will share...really appreciate. .

 

I wonder why you're hitting values such as 9.8-10.1?! That's too rich!
O2 sensor has nothing to do with open loop fueling.
I can think of two possibilities, your fuel pump is going bad & can't keep up with high boost, or it could be an electrical issue, fuel pump wiring.

 

Hi foxbat, thanks for your reply,
I did change new pump, from walbro 255 to DW380, and I did the additional relay pump due to in my reading, Evo 7 had pump amp issues.
The fuel pressure is good, up to 5.5 bar during hard pull, but again, it's sudden lean at 13.5 to 14 afr then boom sound .. I confirmed that the jerking is not Boost cut because, I'm running low boost..

 

Are running on MAF or SD? It could be an issue with either the MAF or MAP sensor.
Did you encounter the issue immediately after you got the car mapped?
What's the idle fuel pressure?

 

i'm running MAF original evo 7 and I've tried to exchange with another MAF, still have issue , my idle AFR is 14.3 to 15.2.
It's run good on dyno ECU Flashed, but happened on the road...